Chapter

Phylogeny and Evolution of the Cucurbitaceae

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

The Cucurbitaceae family contains about 1000 species in 96 genera. Representatives of all genera (except the extinct Khmeriosicyos) and a large percentage of the species have been sequenced for the ribosomal RNA transcribed spacer regions and variable regions of the plastid and mitochondrial genome. These data have allowed to infer evolutionary relationships in the family. The major phy-logenetic structure of the family is now clear, and this chapter includes an up-to-date phylogenetic scheme with the placement of all genera. The Cucurbitaceae clade originated in mainland Southeast Asia sometime in the Late Cretaceous, and the five deepest evolutionary divergences in the family all date to the Late Cretaceous, 70–80 Ma. Two of these ancient clades, the Gomphogyneae and Actinostemma, are now almost restricted to Asia. A third ancient group, the Triceratieae, is mainly Neotropical, except one African genus; other clades and tribes are more widespread. The economically most important genera are concentrated in the Cucurbiteae and Benincaseae, and species of Cucumis and Citrullus, with well-annotated genomes, therefore have largely comparable (homologous) linkage groups. In contrast to the relatively good data on the family's phylogeny, data on its ecology, physiology and morphological evolution are scarce and collection and study of wild species, many of them in threatened habitats is much needed.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... Begoniaceae, Cucurbitaceae, Datiscaceae e Tetramelaceae formam um subclado bem definido morfologicamente denominado core Cucurbitales, devido ao compartilhamento de várias características, incluindo fruto com numerosas sementes, gineceu trímero, ovário ínfero e placentação parietal (Matthews & Endress 2004;Zhang et al. 2006;Renner & Schaefer 2016). ...
... Entretanto, estudos moleculares não forneceram apoio estatístico para o core (Matthews & Endress 2004;Schaefer & Renner 2011;Renner & Schaefer 2016). Além disso, as relações precisas entre as quatro famílias não estão totalmente compreendidas, com Begoniaceae aparecendo ora como irmã de Datiscaceae, ora de Tetramelaceae (Zhang et al. 2006;Schaefer et al. 2009;Schaefer & Renner 2011). ...
... Estudos filogenéticos anteriores da ordem Cucurbitales, baseados numa combinação de regiões plastidiais, mitocondriais e nucleares mostram hipóteses de relacionamentos incertos entre as 4 famílias (Zhang et al. 2006;Schaefer & Renner 2011;Renner & Schaefer 2016). ...
... Cucurbits are distinguished from their closer relatives by the presence of tendrils, a specialized organ that allows them to adopt a climbing habit. This family exhibits a complex evolutionary history and contains many species of agronomical value such as pumpkins and squashes (Cucurbita spp.), watermelon (Citrullus lanatus), muskmelon (Cucumis melo), cucumber (Cucumis sativus), wax gourd (Benincasa hispida), bottle gourd (Lagenaria siceraria), chayote (Sechium edule), bitter gourd (Momordica charantia), and loofahs (Luffa sp.) (Renner and Schaefer, 2016). Previous studies uncovered two WGD events in this family: a cucurbit-common tetraploidization event (CCT) that predated (and possibly contributed to) the origin of the family (Wang et al., 2018), and a more recent allotetraploidization event shared by all species of Cucurbita (Sun et al., 2017;Montero-Pau et al., 2018). ...
... They identified four independent WGDs in the family, analyzed the changes in important morphological traits, and detected four peaks of diversification rates ( Figure 1). The key contribution is the reconstruction of a wellsupported phylogeny of Cucurbitaceae with a high taxonomic sampling using 1503 orthogroups of nuclear genes, recovering a phylogeny that is mostly congruent with previous studies (Renner and Schaefer, 2016), while resolving most of the phylogenetic positions at the tribe level that had low resolution in the phylogenomic study by Bellot et al. (2020). Guo et al. (2020) found two important differences in tree topology compared with previous studies: the relationships between Benincaseae, Coniandreae, and Cucurbiteae, and a difference in the position of Actinostemmateae as a basal group alongside Gomphogyneae. ...
... Guo et al. (2020) found two important differences in tree topology compared with previous studies: the relationships between Benincaseae, Coniandreae, and Cucurbiteae, and a difference in the position of Actinostemmateae as a basal group alongside Gomphogyneae. The phylogenetic position of Indofevilleeae remains unresolved, as two of the topologies retrieved by Guo et al. (2020) placed it as a sister group of Thladiantheae, while the other four topologies placed Indofevilleeae as the basal tribe of Cucurbitoideae, as previously reported by Renner and Schaefer (2016). The phylogenetic relationships reconstructed by Guo et al. (2020) agree with several morphological traits shared between the tribes in Cucurbitaceae, further supporting their results. ...
Article
Full-text available
Whole-genome duplications (WGDs) are regarded as important drivers of macroevolution in plants (Clark and Donoghue, 2018). However, there are few studies that test a connection between WGDs and evolutionary novelty. The proper study of evolutionary patterns related to WGDs needs a well-resolved phylogeny, accurate dates of the WGD events, and historical reconstructions of the evolutionary novelties (Clark and Donoghue, 2018). The advent of exhaustive phylogenomic studies is becoming a promising way to solve these issues, as whole-genome data can help clarify obscure phylogenetic relationships, evaluate patterns associated with WGDs, and track down the evolution of life-history traits that shaped plant lineages (Bellot et al., 2020).
... The Cucurbitaceae family contains between 96 to 118 genera and 825 to 1000 species [42] [43] [44]. The main morphological characteristics that represents most of the cucurbits are: hairy climbers' habit, long root system, branched stem, simple 3 -5 lobed leaves, palmate form being most common, tendrils (simple, bifid or absent), unisexual flowers (yellow and whitish), inferior ovary with parental placentation, high number of large seeds, and the cucurbitacin presence [44] [45]. ...
... The Cucurbitaceae family contains between 96 to 118 genera and 825 to 1000 species [42] [43] [44]. The main morphological characteristics that represents most of the cucurbits are: hairy climbers' habit, long root system, branched stem, simple 3 -5 lobed leaves, palmate form being most common, tendrils (simple, bifid or absent), unisexual flowers (yellow and whitish), inferior ovary with parental placentation, high number of large seeds, and the cucurbitacin presence [44] [45]. Related with the sexual system dioecy was proposed to be the ancestral condition of this group, an example of this situation was described on Bryona genus has been analyzed [46]. ...
... The family Cucurbitaceae is second only after the Solanaceae for its economic importance among horticultural species worldwide, containing about 1000 species in 96 genera [1]. Cucurbits are generally prized for their delicious fruits, which might be low in nutritional value, but can be significant dietary sources of minerals and vitamins, some even with medical values. ...
... This research was supported by the National Natural Science Foundation of China (31571247), the grants from the earmarked fund for the China Agriculture Research System (CARS- , and the Agricultural Science and Technology Innovation Program (ASTIP), Chinese Academy of Agricultural Sciences (CAAS-ASTIP-2018-ZFRI-08). 1 ...
Article
Full-text available
Background: Cucurbits produce fruits or vegetables that have great dietary importance and economic significance worldwide. The published genomes of at least 11 cucurbit species are boosting gene mining and novel breeding strategies, however genetic transformation in cucurbits is impractical as a tool for gene function validation due to low transformation efficiency. Virus-induced gene silencing (VIGS) is a potential alternative tool. So far, very few ideal VIGS vectors are available for cucurbits. Results: Here, we describe a new VIGS vector derived from cucumber green mottle mosaic virus (CGMMV), a monopartite virus that infects cucurbits naturally. We show that the CGMMV vector is competent to induce efficient silencing of the phytoene desaturase (PDS) gene in the model plant Nicotiana benthamiana and in cucurbits, including watermelon, melon, cucumber and bottle gourd. Infection with the CGMMV vector harboring PDS sequences of 69-300 bp in length in the form of sense-oriented or hairpin cDNAs resulted in photobleaching phenotypes in N. benthamiana and cucurbits by PDS silencing. Additional results reflect that silencing of the PDS gene could persist for over two months and the silencing effect of CGMMV-based vectors could be passaged. Conclusions: These results demonstrate that CGMMV vector could serve as a powerful and easy-to-use tool for characterizing gene function, controlling viral pathogens or even performing resistance breeding in cucurbits. Moreover, this study will possess considerable important reference value for developing different viral vectors.
... An early molecular phylogeny of Cucurbitaceae was reconstructed using five chloroplast markers; this phylogeny weakly supported the two subfamilies Cucurbitoideae and Nhandiroboideae, and recovered eight of the 11 tribes as defined by Jeffery (Kocyan et al., 2007). Recent Cucurbitaceae phylogenetic analyses using 14 molecular markers from nuclear, plastid, and mitochondrial genomes (Schaefer andRenner, 2011a, 2011b;Renner and Schaefer, 2016) resulted in a new classification with 15 tribes and 95-97 genera. However, the backbone relationships of tribes are still unresolved possibly due to the limited phylogenetic signals of the molecular markers, a large proportion (over 70%) of which have missing data (Schaefer and Renner, 2011a). ...
... The resulting phylogenies are overwhelmingly congruent with strongly supported monophyly and relationships as summarized in Figure 1. Specifically, the Cucurbitaceae family is monophyletic with maximal support (bootstrap support [BS] = 100%), with high support (BS R 99%) for monophyly of each of the 13 tribes represented by two or more species (with Indofevilleeae being monotypic and Siraitieae represented by one species), consistent with previous phylogenetic studies (Supplemental Figure 8) (Zhang et al., 2006;Kocyan et al., 2007;Schaefer et al., 2009;Schaefer and Renner, 2011a;Renner and Schaefer, 2016). ...
Article
Full-text available
The ability of climbing plants to grow upward along others to reach canopy for photosynthesis is hypothesized as a key innovation in flowering plants. Cucurbitaceae, a family containing ∼1000 species and many important crops, are mostly climbers and have characteristic tendrils and pepo fruits. Here, we present 127 newly sequenced transcriptomes and genomes along with other datasets for a total of 136 cucurbits representing all tribes to establish a robust Cucurbitaceae phylogeny containing eight highly resolved major clades. We analyzed whole genome duplication (WGD), diversification dynamics and ancestral morphologies, and found that after early genome duplication event(s), a burst of diversification and morphological innovations in flower, fruit and root characters occurred under the climate optimum in the Early Eocene. Species radiation under Mid-Eocene Climatic Optimum also coincided with several morphological changes shared by 80% of cucurbits. We found that the cucurbit-specific tendril identity gene TEN originated from a paleo-polyploidization at the origin of the family. Our results support the hypothesis that cucurbit diversifications were probably driven by increased genetic diversity following polyploidizations and novel state of traits under paleo-climate upheavals. This study provides a phylogenetic framework and new insights into morphological and genomic changes facilitating the adaptive evolution of Cucurbitaceae.
... Other names include sweet melon, round melon, muskmelon, casaba, cantaloupe and winter melon (Nayar and Singh 1998;. Melon belongs to the gourd family (Cucurbitaceae) which has 120 genera and around 1000 species, including numerous crops, such as cucumber (Cucumis sativus L.), bitter gourd (Momordica charantia L.), watermelon (Citrullus lanatus Thunb), preserving melon (Citrullus amarus Schrad), squash and zucchini (Cucurbita pepo L.), and bottle gourd (Lagenaria siceraria L.) (Renner and Schaefer 2016;Schaefer and Renner 2011). Melon is divided into two subspecies, C. melo ssp. ...
Book
Plant breeders and geneticists are under constant pressure to sustain and expand food production by using innovative breeding strategies and introducing minor crops, which are well adapted to marginal lands, provide a source of nutrition, and have abiotic and biotic stress tolerance, to feed an ever-increasing human population. The basic concept of this book is to examine the use of innovative methods, augmenting traditional plant breeding, towards the improvement and development of new crop varieties, under the increasingly limiting environmental and cultivation factors, to achieve sustainable agricultural production and enhanced food security. Three volumes of the book series Advances in Plant Breeding Strategies were published in 2015, 2016 and 2018, respectively: Volume 1. Breeding, Biotechnology and Molecular Tools; Volume 2. Agronomic, Abiotic and Biotic Stress Traits and Volume 3. Fruits. In 2019, the following four volumes were published: Volume 4. Nut and Beverage Crops, Volume 5. Cereals, Volume 6. Industrial and Food Crops and Volume 7. Legumes. Recent volumes published in 2021 include: Volume 8. Vegetable Crops: Bulbs, Roots and Tubers, Volume 9. Vegetable Crops: Fruits and Young Shoots and Volume 10. Vegetable Crops: Leaves, Flowerheads, Green Pods, Mushrooms and Truffles. This Volume 9, subtitled Vegetable Crops: Fruits and Young Shoots, consists of 12 chapters focusing on advances in breeding strategies using both traditional and modern approaches for the improvement of individual vegetable crops. Chapters are arranged in 2 parts according to the edible vegetable parts. Part I: Fruits - Bell Pepper, Chili pepper, Bitter gourd, Bottle gourd, Eggplant, Okra, Plantain, Sweet gourd, Melon, Tomato and Zucchini and Part II: Young shoots - Asparagus. Each chapter comprehensively reviews the contemporary literature on the subject and reflects the experiences of the authors. Chapters are written by internationally-reputable scientists and subjected to a review process to assure quality presentation and scientific accuracy. Each chapter begins with an introduction covering related backgrounds and provides in-depth discussion of the subject supported with high-quality color photos, illustrations and relevant data. The chapter concludes with recommendations for future research directions, a comprehensive list of pertinent references to facilitate further reading, and appendixes of genetic resources and concerned research institutes. This book series is a valuable resource for advanced students, researchers, scientists, commercial producers and seed companies as well as consultants and policymakers interested in agriculture, particularly in modern breeding technologies.
... Subsequent radiation throughout central and southern latitudes resulted in broad distribution in Asia, Australia, Africa, and Meso-and South America. Studies described in Chap. 2 (Renner and Schaefer 2016) indicate that there are still more cucurbits to be discovered. Every sequencing project to date has uncovered new species; even new relatives of economically important crops have been found. ...
Chapter
Full-text available
The Cucurbitaceae family includes many high-value and flavorful crops consumed as vegetables, fruits, and seeds in diets throughout the world (Chap. 1, McCreight 2016). Crops such as squashes and pumpkins (Cucurbita pepo, maxima and moschata), cucumbers (Cucumis sativus), melons (Cucumis melo) and watermelons (Citrullus lanatus), make significant contributions to human nutrition. In the past decade we have seen tremendous progress with respect to genomic technologies, and cucurbit crops, with their small genome sizes [~367, 450, 385, and 400 Mbp for cucumber, melon, watermelon, and squash, respectively], have benefitted richly from these advances. The recent assemblies of draft genome sequences for the four major cucurbit species make it feasible to identify, characterize and utilize genes in ways that were not possible even a few years ago. This volume explored the genetic diversity of cucurbit crops, advances to unravel cucurbit genomes, and evolving applications of genomics to understand cucurbit growth, development and adaptation to their environments.
... Benincaseae tribes (Renner and Schaefer, 2016). We present high-quality draft genome sequences of two Cucurbita species of the Cucurbiteae, C. maxima and C. moschata, as well as evidence for an ancient allotetraploidy event in Cucurbita. ...
Article
The Cucurbita genus contains several economically important species in the Cucurbitaceae family. Here we report high-quality genome sequences of C. maxima and C. moschata and provide evidence supporting an allotetraploidization event in Cucurbita. We are able to partition the genome into two homoeologous subgenomes based on different genetic distances to melon, cucumber and watermelon in the Benincaseae tribe. We estimate that the two diploid progenitors successively diverged from Benincaseae around 31 and 26 million years ago (Mya), and the allotetraploidization happened at some point between 26 Mya and 3 Mya, the estimated date when C. maxima and C. moschata diverged. The subgenomes have largely maintained the chromosome structures of their diploid progenitors. Such long-term karyotype stability after polyploidization has not been commonly observed in plant polyploids. The two subgenomes have retained similar numbers of genes, and neither subgenome is globally dominant in gene expression. Allele-specific expression analysis in the C. maxima × C. moschata interspecific F1 hybrid and the two parents indicates the predominance of trans-regulatory effects underlying expression divergence of the parents, and detects transgressive gene expression changes in the hybrid correlated with heterosis in important agronomic traits. Our study provides insights into polyploid genome evolution and valuable resources for genetic improvement of cucurbit crops.
... It has low calories and contains antioxidant substances such as lycopene (Laínez Orrala, 2009). There are different varieties of watermelon, with different characteristics that determine the fruit quality (Renner and Schaefer, 2016;Suárez-Hernández et al., 2017) and its successful conditions in the national, regional and international markets (Canales, 1998;FAO, 2011;Barba and Suris, 2015). ...
Article
Full-text available
Empirical planting techniques, little knowledge of appropriate pruning methods, and the continued use of synthetic fertilizers can trigger low productivity features, and consequently poor fruit quality in watermelon cultivation. The present investigation was aimed to determine these objectives: a) the best crop performance by using three spacing, b) two types of organic fertilizers and c) two types of pruning on the development and quality of fruit. The three factors were studied under the followings: 1) spacing factor (SF) including 1 m x 2.5 m, 1 m x 3 m, 2.5m x 2.5 m, 2) pruning (PF) including 1 and 2 axes, and Muñoz-Rengifo et al., Methods improving watermelon fruit development and quality Bioscience Research, 2018 volume 15(3): 1462-1471 1463 3) Organic fertilizers (OF) including earthworm humus and Biol elaborated from biological waste. The best behavior for the fruit length and perimeter variables was linked to the spacing 1 m x 2.5 m, and to the 2-axis pruning. Likewise, with the 2-axis pruning, fruits with higher sweetness were obtained, represented in Brix Grades. These results allow to recommend the use of the two organic fertilizers: biol and humus respectively as potential elements for the vegetable nutrition of watermelon crop, guaranteeing an adequate quality of fruits, but overall avoiding the use of chemical fertilizer.
... This review synthesises recent insights with older studies to produce a big picture of the domestication of Cucurbitaceae crops, highlighting different domestication trajectories as informed by phylogenetics, archaeology and genomics. The gourd family (Cucurbitaceae) has c. 1000 species, including numerous crops, such as cucumber (Cucumis sativus), bitter gourd (Momordica charantia), watermelon (Citrullus lanatus), preserving melon (Citrullus amarus), honey melon (Cucumis melo), squash and zucchini (Cucurbita pepo), and bottle gourd (Lagenaria siceraria) (Schaefer & Renner, 2011a,b;Renner & Schaefer, 2016;Fig. 1). ...
Article
Full-text available
Some of the World's most valuable crops, including watermelon, honey melon, cucumber, squash, zucchini, and pumpkin, belong to the family Cucurbitaceae. We review insights on their domestication from new phylogenies, archaeology, and genomic studies. Ancestral state estimation on the most‐complete Cucurbitaceae phylogeny to date suggests that an annual life cycle may have contributed to domestication. Domestication started by 11,000 years ago in the New World and Asia, and apparently more recently in Africa. Some cucurbit crops were domesticated only once, others multiple times (e.g., melon from different Asian and African populations). Most wild cucurbit fruits are bitter and non‐palatable to humans, and non‐bitterness of the pulp apparently was a trait favoured early during domestication, with genomic data showing how bitterness loss was achieved convergently. The genetic pathways underlying lycopene accumulation, red or orange pulp colour, and fruit size and shape are only beginning to be understood. The study of cucurbit domestication in recent years has benefitted from the increasing integration of archaeological and genomic data with insights from herbarium collections, the most efficient way to understand species' natural geographic ranges and climate adaptations. This article is protected by copyright. All rights reserved.
... The family Cucurbitaceae is second only after the Solanaceae for its economic 52 importance among horticultural species worldwide, containing about 1000 species in 53 96 genera (Renner and Schaefer, 2016). Cucurbits are generally prized for their 54 delicious fruits, which might be low in nutritional value, but can be significant dietary In the past decades, a large number of viral vectors had been developed as 77 powerful tools for the functional verification of genes in plants (Ruiz et al., 1998;Liu 78 et al., 2002;Ding et al., 2006;Igarashi et al., 2009;Zhang et al., 2010;Sempere et al., 79 2011;Liu et al., 2016;Wang et al., 2016). ...
Preprint
Full-text available
Cucurbits produce fruits or vegetables that have great dietary importance and economic significance worldwide. The published genomes of at least 11 cucurbit species are boosting gene mining and novel breeding strategies, however genetic transformation in cucurbits is impractical as a tool for gene function validation due to low transformation efficiencies. Virus-induced gene silencing (VIGS) is a potential alternative tool. So far, very few ideal VIGS vectors are available for cucurbits. Here, we describe a new VIGS vector derived from cucumber green mottle mosaic virus (CGMMV), a monopartite virus that infects cucurbits naturally. We show that the CGMMV vector is competent to induce efficient silencing of the phytoene desaturase ( PDS ) gene in the model plant Nicotiana benthamiana and in cucurbits, including watermelon, melon, cucumber and bottle gourd. Infection with the CGMMV vector harboring PDS sequences of 69-300 bp in length in the form of sense-oriented or hairpin cDNAs resulted in photobleaching phenotypes in N. benthamiana and cucurbits by PDS silencing. Additional results reflect that silencing of the PDS gene could persist for over two months and the silencing effect of CGMMV-based vectors could be passaged. These results demonstrate that CGMMV vector could serve as a powerful and easy-to-use tool for characterizing gene function in cucurbits. One sentence summary A CGMMV-based vector enables gene function studies in cucurbits, an extremely low efficiency species for genetic transformation.
... The bottle gourd (Lagenaria siceraria, 2n = 2× = 22), a member of the Cucurbitaceae family [1], is an important horticultural and medicinal crop [2]. It originated in Africa and was independently domesticated in Africa and Asia [3]. The fruit of bottle gourd can be used as vegetable, utensil, ornamental, and even as a musical instrument. ...
Article
Full-text available
The bottle gourd (Lagenaria siceraria) is an important horticultural and medicinal crop with high nutritional value. This study aimed at examining the molecular regulation of fruit size in bottle gourd. We performed transcriptome sequencing of two bottle gourd cultivars differing in their fruit size. The average fruit length and weight of the cultivar Hang (39.48 cm/624.4 g) were higher than those of the cultivar USA (10.34 cm/152.8 g) at maturity. Transcriptome sequencing and assembly resulted in 89,347 unigenes. A total of 1250 differentially expressed genes (DEG) were found between the two cultivars, including 422 upregulated genes and 828 downregulated genes in Hang as compared to USA. Genes related to cell wall metabolism, phytohormones, cell cycle, and cell division showed significant differential expression between the two cultivars. DEGs encoding transcription factors (TF) from nine TF families were also identified. The ethylene response factor family was the most enriched among these families. Our study provides a basis for further investigations of the molecular regulation of fruit size in bottle gourd.
... One exception is the bottle-trunked succulent tree Dendrosicyos socotranus Balf.f., originally described as Dendrosicyos socotrana (Balfour 1888) and recently renamed to fit the grammatical gender (IPNI 2020; Renner and Schaefer 2016). The tree belongs to a monospecific genus placed in the Cucurbitoidae subfamily and Coniandreae tribe; it is restricted to the Socotra archipelago where it has been estimated to have diverged from its closest relatives some 14 (8-19) million years ago (Renner and Schaefer 2016). The species is characterized by typical swollen waterstoring trunk (Miller 2004), pendulous branches and absent tendrils (Olson 2003). ...
Article
We conducted a study throughout Socotra Island (Yemen) to investigate the distribution, population structure and regeneration potential of the endemic and threatened tree species Dendrosicyos socotranus, the Cucumber Tree. In total, 163 live trees (excluding seedlings) were found in all (24) investigated locations, covering an area of 96 km2. The height, stem circumference, fertility and coordinates of each tree were measured and data regarding the ecotope, land cover and natural regeneration were recorded. We estimated that there could be more than 6400 Cucumber Tree individuals among the populations on Socotra Island. The majority of the trees occur in the “high Shrubland with succulents” and “wadi” land cover classes. In general, the fertility of the trees is good, and natural regeneration occurred in 77% of the locations with adult trees; it was found that 16% of the individual trees regenerated. Our study, collecting data on the regeneration of the species and estimating the size of local populations for the first time, can be used for local conservation and future monitoring of this important, endangered Socotran endemic.
... No reuse allowed without permission. 41 . We present high-quality draft genome sequences of two Cucurbita species of the Cucurbiteae, C. maxima and C. moschata, as well as evidence for an ancient allotetraploidy event in Cucurbita. ...
Preprint
The Cucurbita genus contains several economically important species in the Cucurbitaceae family. Interspecific hybrids between C. maxima and C. moschata are widely used as rootstocks for other cucurbit crops. We report high-quality genome sequences of C. maxima and C. moschata and provide evidence supporting an allotetraploidization event in Cucurbita . We are able to partition the genome into two homoeologous subgenomes based on different genetic distances to melon, cucumber and watermelon in the Benincaseae tribe. We estimate that the two diploid progenitors successively diverged from Benincaseae around 31 and 26 million years ago (Mya), and the allotetraploidization happened earlier than 3 Mya, when C. maxima and C. moschata diverged. The subgenomes have largely maintained the chromosome structures of their diploid progenitors. Such long-term karyotype stability after polyploidization is uncommon in plant polyploids. The two subgenomes have retained similar numbers of genes, and neither subgenome is globally dominant in gene expression. Allele-specific expression analysis in the C. maxima × C. moschata interspecific F 1 hybrid and the two parents indicates the predominance of trans- regulatory effects underlying expression divergence of the parents, and detects transgressive gene expression changes in the hybrid correlated with heterosis in important agronomic traits. Our study provides insights into plant genome evolution and valuable resources for genetic improvement of cucurbit crops.
... Trichosanthes cucumerina L. belongs to the family Trichosanthes which is the one of the important family of Cucurbitaceae [7]. Trichosanthes L. is the largest genus of the cucurbitaecae with 918 species [8][9][10][11][12][13][14][15][16][17]. Trichosanthes has two cultivated species Trichosanthes anguina L. and Trichosanthes dioca Roxb and several wild species [18]. ...
... The Cucurbitaceae family comprises approximately 1000 species, including numerous fruit crops and vegetables worldwide, and has signi cant economic importance [43]. Wild species of Cucurbitaceae have rich genetic diversity, which can help them adapt to different environmental conditions. ...
Preprint
Full-text available
Background This is the first study on seed germination of Cucumis prophetarum in the Arabian Peninsula. Light and temperature as the main environmental factors and seed storage conditions greatly affect the germination of many Cucurbitaceae species. C. prophetarum is the perennial prostrate with woody rootstocks that grow throughout the year in the arid Arabian deserts. We examined the effects of seed storage conditions and sterilization by sodium hypochlorite (NaOCL) on germination of C. prophetarum seeds. Matured, fresh and field stored seeds were collected in March of 2016 and 2017 from a population in the United Arab Emirates. Fresh and the stored seeds (field, freeze, and room temperature) were germinated at three temperature regimes (15/25, 20/30 and 25/35°C) in both continuous darkness and alternating 12 h light/12 h darkness. Results The fresh and freeze stored seeds had higher germination percentage than the field and room temperature stored seeds. High germination was recorded in both lower and moderate temperatures (15/25 and 20/30°C) in light conditions. Sterilization of the seeds by NaOCl had a negative effect on the speed and germination percentage under all storage conditions, and it changes light and temperature requirements of seeds for germination. Conclusions Germination of C. prophetarum is sensitive to incubation light and temperature as well as to the seed storage conditions. The germination ability of stored seeds indicates that seed storage behaviour of C. prophetarum is orthodox. Light and temperature requirements for seed germination reflects a suitable place, habitat, and time for seedling emergence of C. prophetarum. The effect of NaOCl treatment on the germination may be associated with concentration and exposure periods of seeds. Therefore, we suggest that when using NaOCl for seed sterilization or to stimulate the germination, caution must be taken for using its concentration and exposure time, especially for species with thin and soft seed coats like C. prophetarum. Further studies on seed germination ecology would help to understand better the adaptive strategy of the C. prophetarum in the arid desert environments.
... . Puis des marqueurs chloroplastiques, nucléaires et mitochondriaux ont permis une mise à jour de la classification néanmoins certaines relations génétiques inter-tribus n'étaient pas résolues(Schaefer et Renner 201;Renner et Schaefer 2016). Très récemment, les analyses faites sur des séquences de génomescomplets et de transcriptomes ont permis de construire une phylogénie bien résolue des Cucurbitacées (Guo et al. 2020). ...
Thesis
La nervation blanche de la courgette (VCZ) affecte les plantules en pépinière et induit des nécroses, des éclaircissements des nervures, des retards et des blocages de croissance. Cette maladie transmise par les semences est causée par des bactéries du complexe d’espèces Pseudomonas syringae (Pssc). La fréquence des lots de semences contaminés croît depuis une 20aine d’années et peu de connaissances épidémiologiques sur la VCZ sont disponibles. L’objectif de cette thèse était de caractériser les souches VCZ et de comprendre comment elles contaminent les graines. Ainsi, 54 souches VCZ ont été caractérisées phylogénétiquement, génotypiquement et phénotypiquement. Des outils moléculaires de détection et d’identification ont été développés grâce aux analyses de génomique comparative et utilisés lors d’une enquête épidémiologique dans des parcelles de courgette porte-graines et dans les lots de semences. Les voies de transmission aux graines de 2 souches VCZ ont été étudiées. Les résultats montrent que les souches VCZ appartiennent à cinq lignées génétiques (Clusters A à E) du phylogroupe 2 du Pssc et possèdent des gammes d’hôtes étroite (Cluster A) ou large (Cluster B à E) au sein des Cucurbitacées en lien avec leur répertoires d’effecteurs de type III. Un nouveau schéma de typage multilocus et une nouvelle q-PCR multiplex mettent en évidence la prédominance des souches du cluster A dans les lots de semences mais pas dans les parcelles en végétation. Les voies transmission florale et vasculaire sont empruntées par 2 souches VCZ des Clusters A et E. Ces données permettant une meilleure compréhension de la VCZ serviront de base à l’amélioration de la lutte contre cette maladie.
... The family Cucurbitaceae is a storehouse of about 1000 species belonging to 96 genera with a great range of diversity (Renner and Schaefer 2016). Among the valuable crop members, Luffa is one prime genus with four species distributed widely in India (Renner and Pandey 2013). ...
Article
Full-text available
India is a repository of many native crop species of the family Cucurbitaceae contributing to the agro-economic growth of the country. Luffa acutangula (L.) Roxb. is one of the major vegetables of Cucurbitaceae with extensive distribution across the eco-climatic zones. Relationships with wild relatives are one of the fundamental requirements to expand the genetic base of cultivated crops like Luffa. We have adopted the enzymatic maceration and air-drying (EMA) method to accomplish comparative karyotype analysis and fluorescence banding patterns on chromosomes of the ridged gourd and its wild relative L. echinata Roxb. The species have 2n=26 chromosomes. The karyotypes of both species have six satellited chromosomes and a predominance of nearly metacentric pairs. Prominent 4′,6-diamidino-2-phenylindole (DAPI) bands have been encountered in all chromosomes of the two species while six distinct chromomycin A3 (CMA) bands were found associated with satellites. The conservation of banding patterns between the species raises the possibility to revise genomic kinships and evolutionary distance. Our study provides a chromosomal dataset of the Indian Luffa germplasm that may be utilized for genome research and programmed breeding strategies.
... Other names include sweet melon, round melon, muskmelon, casaba, cantaloupe and winter melon (Nayar and Singh 1998;. Melon belongs to the gourd family (Cucurbitaceae) which has 120 genera and around 1000 species, including numerous crops, such as cucumber (Cucumis sativus L.), bitter gourd (Momordica charantia L.), watermelon (Citrullus lanatus Thunb), preserving melon (Citrullus amarus Schrad), squash and zucchini (Cucurbita pepo L.), and bottle gourd (Lagenaria siceraria L.) (Renner and Schaefer 2016;Schaefer and Renner 2011). Melon is divided into two subspecies, C. melo ssp. ...
... argyrosperma, C. ficifolia, C. maxima, C. moschata, and C. pepo) are grown worldwide for their edible fruits and seeds (Castellanos-Morales et al. 2018), variously known as squash, pumpkin or gourd. The earliest known evidence of the domestication of Cucurbita is dated 10,000 calendar years B.P. (Renner and Schaefer 2016;Kates et al. 2017;Smith 1997), preceding the domestication of other crops (e.g., for maize is started 8,700 calendar years B.P.). At least six independent domestication events from distinct wild ancestors were identified in domesticated Cucurbita (Sanjur et al. 2002). ...
Article
Full-text available
Main conclusion Genome-wide annotation reveals that the gene birth–death process of the Cucurbita R family is associated with a species-specific diversification of TNL and CNL protein classes. Abstract The Cucurbitaceae family includes nearly 1000 plant species known universally as cucurbits. Cucurbita genus includes many economically important worldwide crops vulnerable to more than 200 pathogens. Therefore, the identification of pathogen-recognition genes is of utmost importance for this genus. The major class of plant-resistance (R) genes encodes nucleotide-binding site and leucine-rich repeat (NLR) proteins, and is divided into three sub-classes namely, TIR-NB-LRR (TNL), CC-NB-LRR (CNL) and RPW8-NB-LRR (RNL). Although the characterization of the NLR gene family has been carried out in important Cucurbita species, this information is still linked to the availability of sequenced genomes. In this study, we analyzed 40 de novo transcriptomes and 5 genome assemblies, which were explored to investigate the Cucurbita expressed-NLR (eNLR) and NLR repertoires using an ad hoc gene annotation approach. Over 1850 NLR-encoding genes were identified, finely characterized and compared to 96 well-characterized plant R-genes. The maximum likelihood analyses revealed an unusual diversification of CNL/TNL genes and a strong RNL conservation. Indeed, several gene gain and loss events have shaped the Cucurbita NLR family. Finally, to provide a first validation step Cucurbita, eNLRs were explored by real-time PCR analysis. The NLR repertories of the 12 Cucurbita species presented in this paper will be useful to discover novel R-genes.
... Other names include sweet melon, round melon, muskmelon, casaba, cantaloupe and winter melon (Nayar and Singh 1998;. Melon belongs to the gourd family (Cucurbitaceae) which has 120 genera and around 1000 species, including numerous crops, such as cucumber (Cucumis sativus L.), bitter gourd (Momordica charantia L.), watermelon (Citrullus lanatus Thunb), preserving melon (Citrullus amarus Schrad), squash and zucchini (Cucurbita pepo L.), and bottle gourd (Lagenaria siceraria L.) (Renner and Schaefer 2016;Schaefer and Renner 2011). Melon is divided into two subspecies, C. melo ssp. ...
Chapter
Full-text available
Cultivated melons have spread through trade and exploration from centers of origin in Asia to Europe and the Americas and are important in local, regional and world trade. Iran ranks second in world melon production (Cucumis melo L.), generating over 1.7 million mt in 2018. Local farmers prefer to cultivate melon groups based on yield, fruit sweetness, firmness and color. However, some groups like Dudaim and Flexuosus have high fragrance and adaptation to warm and dry season; and are distributed in different culture regions. Since standard melon cultivars have evolved and been introduced, most commercial types exhibit variable, late female flower production and, consequently, late fruit ripening which are encountered with unfavorable condition of late season ripening, disease susceptibility and cucurbit fly as a critical problem of field melon production. Melons are cross-pollinated crops without inbreeding depression and are well suited to heterosis breeding. Furthermore, access to monoecious or gynoecious lines in commercial and popular melons with andromonoecious sex expression could reduce time and cost for emasculation and accelerate hybrid production. Priority of melon breeding should be given to produce multiple disease resistance, fruit size and uniformity, fruit quality attributes (color, mild aroma, firmness, thickness) and good shelf life for storage to reduced postharvest loss. This chapter reviews and explores the past, present and future prospect of melon breeding relative to Flexuosus and Dudaim Groups as genetic resources, flower and fruit attributes and also organic volatile compounds.
... The family Cucurbitaceae contains an extensive range of diversity consisting of about 1000 species spread over 96 genera (Renner and Schaefer 2017). The diversity of plant families is associated with variation in genome sizes and chromosome numbers as a result of enormous adaptive radiation (Soltis et al. 2004;Lysák and Schubert 2013). ...
Article
Full-text available
The cytogenetic relationships in the species of Cucurbitaceae are becoming immensely important to answer questions pertaining to genome evolution. Here, a simplified and updated data resource on cytoge-netics of Cucurbitaceae is presented on the basis of foundational parameters (basic, zygotic and gametic chromosome numbers, ploidy, genome size, karyotype) and molecular cytogenetics. We have revised and collated our own findings on seven agriculturally important Indian cucurbit species in a comparative account with the globally published reports. Chromosome count (of around 19% species) shows nearly threefold differences while genome size (of nearly 5% species) shows 5.84-fold differences across the species. There is no significant correlation between chromosome numbers and nuclear genome sizes. The possible trend of evolution is discussed here based on molecular cytogenetics data, especially the types and distribution of nucleolus organizer regions (NORs). The review supersedes the scopes of general chromosome databases and invites scopes for continuous updates. The offline resource serves as an exclusive toolkit for research and breeding communities across the globe and also opens scope for future establishment of web-database on Cucurbitaceae cytogenetics.
... The genus Cucumis belongs to the gourd family Cucurbitaceae and comprises two economically important cucurbit crops, cucumber and melon, grown worldwide. This gourd family consists of around 130 genera and 1,000 species containing several nutritionally important cucurbitaceous vegetables, like Citrullus lanatus, Citrullus amarus, Momordica charantia, Cucurbita pepo, Lagenaria siceraria, Benincasa hispida, Luffa and Trichoanthes species (Renner and Schaefer 2016;Chomicki et al. 2019). With the annexing of Asian and Australian species, so far approximately 66 species have been documented in the genus Cucumis Chomicki et al. 2019;Cheng et al. 2020). ...
Chapter
Full-text available
Cucumber (Cucumis sativus L.) is an important vegetable crop cultivated world widely. Many pathogens can infect cucumber to cause great losses of fruit yield and quality, including bacteria, fungi and viruses. Because of the complex system of plant, pathogen and environment, the disease resistance is complicated and involved many genes, researched commonly as quantitative trait. In cucumber, recent studies focus on mapping QTLs (quantitative trait locus) of disease resistance. We try to make a brief summary of QTL mapping for disease resistance in cucumber, excluding those disease resistances as quality traits.
... Other names include sweet melon, round melon, muskmelon, casaba, cantaloupe and winter melon (Nayar and Singh 1998;. Melon belongs to the gourd family (Cucurbitaceae) which has 120 genera and around 1000 species, including numerous crops, such as cucumber (Cucumis sativus L.), bitter gourd (Momordica charantia L.), watermelon (Citrullus lanatus Thunb), preserving melon (Citrullus amarus Schrad), squash and zucchini (Cucurbita pepo L.), and bottle gourd (Lagenaria siceraria L.) (Renner and Schaefer 2016;Schaefer and Renner 2011). Melon is divided into two subspecies, C. melo ssp. ...
Chapter
Bitter gourd is valuable for its nutrients and medicinal properties, but neglected in terms of genetic inheritance and molecular breeding. Single plant selection, mass selection, pedigree selection and bulk population improvement methods are commonly used in bitter gourd. Heterosis breeding (F1 hybrids) is a new approach by using gynoecious and precautious gynoecious lines. Rootstock breeding is another area to address biotic and abiotic stresses in bitter gourd. Scanty information is available on the use of molecular markers including random amplification of polymorphic DNA (RAPD), amplified fragment length polymorphism (AFLP), simple sequence repeats (SSR) and inter-simple sequence repeat (ISSR). Reduced representation sequencing (RRS) methodologies like restriction-associated DNA tag sequencing (RAD-seq) analysis and genotyping-by-sequencing (GBS) technology used to map gynoecy and other economic traits. The SNP marker TP_54890 found at a distance of 3.04 cM to gynoecious (gy-1) locus on linkage group 12. This marker will be extremely useful in MAS for the rapid development of new varieties and hybrids in bitter gourd. The draft genome sequence (285.5 Mb ~84%) of bitter gourd will act as a reference genome for future genomic studies. The availability of advanced molecular tools will complement conventional breeding used to accelerate genetic gain in bitter gourd. This chapter discusses conventional breeding, distant hybridization, genetic inheritance and QTLs mapping of horticultural traits along with tissue culture aspects in bitter gourd.
... The genus Cucumis belongs to the gourd family Cucurbitaceae and comprises two economically important cucurbit crops, cucumber and melon, grown worldwide. This gourd family consists of around 130 genera and 1,000 species containing several nutritionally important cucurbitaceous vegetables, like Citrullus lanatus, Citrullus amarus, Momordica charantia, Cucurbita pepo, Lagenaria siceraria, Benincasa hispida, Luffa and Trichoanthes species (Renner and Schaefer 2016;Chomicki et al. 2019). With the annexing of Asian and Australian species, so far approximately 66 species have been documented in the genus Cucumis Chomicki et al. 2019;Cheng et al. 2020). ...
Chapter
Abiotic stress is one of the severe stresses of the environment that threats to the growth and production of any plant worldwide. During the past decade, several studies have been published on molecular mapping of abiotic stress resistance in cucumber. Here, we summarize the relevant quantitative trait loci (QTL) linked to temperature stress, waterlogging stress, drought stress and salinity. These data provided valuable information for future genetic studies and marker-assisted selection and gene cloning for abiotic stress tolerance of cucumber.
Article
Full-text available
Sicyos angulatus (burcucumber) is an annual plant native to the north-eastern America. We investigated the genomic characteristics of the complete chloroplast (CP) genome in S. angulatus with a de novo strategy. The CP genome was 154,986 bp in length including 84 protein coding genes, 37 tRNA genes, and eight rRNA genes. It has large single-copy (LSC) (84,355 bp), small single-copy (SSC) (18,079 bp), and a pair of inverted repeats (IRs) (26,276 bp), which consists of typical quadripartite structure. A phylogenetic analysis of 64 CP genomes from Cucurbitaceae revealed that the Sicyos angulatus was separated from other species and clustered together with Sicyos edulis, which is congruent with previous studies. Infrafamilial classification system inferred from our data was also congruent with previous study based on CP DNA data.
Article
Cumaceans are small peracarid crustaceans that can be remarkably diverse and important benthic organisms. Despite their ubiquitous presence in soft sediments, no well‐resolved phylogeny currently exists, which impedes ecological and evolutionary studies of the group. We present a phylogeny based on Bayesian inference of six markers (18S, 28S, 12S, 16S, CytB and COI), which recovers monophyly of the order, a deep split between telson and pleotelson bearing groups, and monophyly of four of the seven included families, including monophyletic Pseudocumatidae, Lampropidae, Bodotriidae and Nannastacidae. The only species representing the family Gynodiastylidae in our dataset was positioned among members of Diastylidae in the phylogenetic analyses. However, this result is based on a single partial COI sequence; thus, we consider it doubtful, and the family Diastylidae are otherwise recovered as a monophyletic family. The family Leuconidae is split into two well‐supported clades, a clade containing Antarctic members of the genus Leucon and a separate clade containing non‐Antarctic members of the genera Leucon and Eudorella. The phylogeny is a great stride forwards, as it supports most families as monophyletic, making generic level phylogenies a plausible endeavour in the future.
Article
Full-text available
Organelle genomes exhibit remarkable diversity in content, structure, and size, and in their modes of gene expression, which are governed by both organelle- and nuclear-encoded machinery. Next generation sequencing (NGS) has generated unprecedented amounts of genomic and transcriptomic data, which can be used to investigate organelle genome transcription. However, most of the available eukaryotic RNA-sequencing (RNA-seq) data are used to study nuclear transcription only, even though large numbers of organelle-derived reads can typically be mined from these experiments. Here, we use publicly available RNA-seq data to assess organelle genome transcription in 59 diverse plastid-bearing species. Our RNA mapping analyses unraveled pervasive (full or near-full) transcription of mitochondrial, plastid, and nucleomorph genomes. In all cases, 85% or more of the organelle genome was recovered from the RNA data, including noncoding (intergenic and intronic) regions. These results reinforce the idea that organelles transcribe all or nearly all of their genomic material and are dependent on post-transcriptional processing of polycistronic transcripts. We explore the possibility that transcribed intergenic regions are producing functional noncoding RNAs, and that organelle genome noncoding content might provide raw material for generating regulatory RNAs.
Article
Full-text available
The first comprehensive phylogenetic study of Euphausiacea (all 86 valid species) is presented. It is based on four molecular markers and 168 morphological characters (including 58 characters of the petasma). Phylogenetic analyses support the monophyly and robustness of the families Bentheuphausidae and Euphausiidae and reveal three major clades for which we erect three new subfamilies: Thysanopodinae, Euphausiinae and Nematoscelinae. All genus‐level clades are statistically supported (except Thysanopoda in molecular analyses), deeply nested within the subfamily‐level clades, and encompass 14 new species groups. Copulatory structures have a major impact on tree topology in the morphological analysis, the removal of which resulted in only half the number of supported clades and genera. We revealed three groups of morphological characters, which are probably coupled with the same biological role and thus interlinked evolutionarily: (i) antennular peduncle and petasma (copulation); (ii) eyes and anterior thoracopods (feeding); and (iii) shape of carapace and pleon (defence). We analysed the evolutionary pathways of the clades into main oceanic biotopes and compared them with morphological adaptations most likely to be coupled with this process.
Article
Full-text available
In cucurbits, CmWIP1 is a master gene controlling sex determination. To bring new insight in the function of CmWIP1, we investigated two Arabidopsis WIP transcription factors, AtWIP1/TT1 and AtWIP2/NTT. Using an inducible system we showed that WIPs are powerful inhibitor of growth and inducer of cell death. Using ChIP-seq and RNA-seq we revealed that most of the up-regulated genes bound by WIPs display a W-box motif, associated with stress signaling. In contrast, the down-regulated genes contain a GAGA motif, a known target of polycomb repressive complex. To validate the role of WIP proteins in inhibition of growth, we expressed AtWIP1/TT1 in carpel primordia and obtained male flowers, mimicking CmWIP1 function in melon. Using other promoters, we further demonstrated that WIPs can trigger growth arrest of both vegetative and reproductive organs. Our data supports an evolutionary conserved role of WIPs in recruiting gene networks controlling growth and adaptation to stress.
Article
Full-text available
Benincasa hispida (wax gourd) is an important Cucurbitaceae crop, with enormous economic and medicinal importance. Here, we report the de novo assembly and annotation of the complete chloroplast genome of wax gourd with 156,758 bp in total. The quadripartite structure of the chloroplast genome comprises a large single-copy (LSC) region with 86,538 bp and a small single-copy (SSC) region with 18,060 bp, separated by a pair of inverted repeats (IRa and IRb) with 26,080 bp each. Comparison analyses among B. hispida and three other species from Benincaseae presented a significant conversion regarding nucleotide content, genome structure, codon usage, synonymous and non-synonymous substitutions, putative RNA editing sites, microsatellites, and oligonucleotide repeats. The LSC and SSC regions were found to be much more varied than the IR regions through a divergent analysis of the species within Benincaseae. Notable IR contractions and expansions were observed, suggesting a difference in genome size, gene duplication and deletion, and the presence of pseudogenes. Intronic gene sequences, such as trnR-UCU–atpA and atpH–atpI, were observed as highly divergent regions. Two types of phylogenetic analysis based on the complete cp genome and 72 genes suggested sister relationships between B. hispida with the Citrullus, Lagenaria, and Cucumis. Variations and consistency with previous studies regarding phylogenetic relationships are discussed. The cp genome of B. hispida provides valuable genetic information for the detection of molecular markers, research on taxonomic discrepancies, and the inference of the phylogenetic relationships of Cucurbitaceae.
Chapter
The Cucurbitaceae provide food and sustenance almost the entire world over, in economically advanced areas as well as resource-poor areas, and encompass over two dozen crop plant species. Worldwide, the mostly widely grown and consumed cucurbits are watermelons, melons, cucumbers, squash, and pumpkins. As with all crops, yield quantity and quality of cucurbits is determined by genetics, the environment, and management, and interactions among these three variables. Like other crop plants, the growth, yield, and quality of cucurbits is adversely affected by abiotic stresses. This overview is devoted to the possibility of developing cucurbits more tolerant of abiotic stresses by manipulating their genomes. Descriptive background information is provided on cucurbit plants and their distribution in the wild and under cultivation, breeding achievements, and the abiotic stresses affecting cucurbits. The presentation then discusses the limitations of traditional cucurbit breeding for stress tolerance, diversity analysis of cucurbits, association mapping in cucurbits, gene identification through genome-wide analysis, genome-wide association studies for identifying quantitative trait loci, prospects and limitations for marker-assisted breeding for stress tolerance in cucurbits, and the rather limited progress and insights gained so far from research on cucurbit genomics. Much more research in genomic designing for abiotic stress tolerance of cucurbits needs to be conducted, by screening of germplasm collections for abiotic stress tolerance and by discovering the target genes and their locations within the genome.
Article
The genetic architecture of quantitative traits is determined by both Mendelian and polygenic factors, yet classic examples of plant domestication focused on selective sweep of newly mutated Mendelian genes. Here we report the chromosome-level genome assembly and the genomic investigation of a nonclassic domestication example, bitter gourd ( Momordica charantia ), an important Asian vegetable and medicinal plant of the family Cucurbitaceae. Population resequencing revealed the divergence between wild and South Asian cultivars about 6,000 y ago, followed by the separation of the Southeast Asian cultivars about 800 y ago, with the latter exhibiting more extreme trait divergence from wild progenitors and stronger signs of selection on fruit traits. Unlike some crops where the largest phenotypic changes and traces of selection happened between wild and cultivar groups, in bitter gourd large differences exist between two regional cultivar groups, likely reflecting the distinct consumer preferences in different countries. Despite breeding efforts toward increasing female flower proportion, a gynoecy locus exhibits complex patterns of balanced polymorphism among haplogroups, with potential signs of selective sweep within haplogroups likely reflecting artificial selection and introgression from cultivars back to wild accessions. Our study highlights the importance to investigate such nonclassic example of domestication showing signs of balancing selection and polygenic trait architecture in addition to classic selective sweep in Mendelian factors.
Chapter
Cucumber is one of the most important vegetable crops grown worldwide, both under open fields and protected conditions. It is originated in India with a secondary centre of diversity in China and the Near East. It is a cross-pollinated crop with no inbreeding depression and is used as a model crop for studying the various genetic and molecular pathways because of its breeding behaviour and smaller genome size. The distribution of the different Cucumis species in the primary, secondary and tertiary gene pool is determined based on cross-compatibility, genetic, phylogenetic and molecular evidence. The cultivated cucumbers are generally monoecious in nature, however, a wide diversity in sex forms is recorded in this species. Gynoecious with only female flower is the most important sex form used commercially in hybrid seed production in cucumber. Significant advancement has been made in understanding the genetics of the flowering traits like sex expression and modification. Studies on inheritance and nature of heritability for important vegetative, fruit and yield-related traits, biotic and abiotic stresses have been reported widely by different research groups. The understanding in the genetics of the important qualitative and quantitative traits facilitated the genomics study in economically important traits. In spite of being highly cross-pollinated in nature, it has very low or negligible inbreeding depression. Different breeding methods are adopted in cucumber based on its genetic architecture and breeding behaviour. Among the popular breeding methods, population improvement, pedigree method and back-cross breeding have been adopted widely in the successful development of elite lines with a wide variety of traits. Because of higher yield and better adaptability and resilience, F1 hybrids are highly popular in cucumber. The development of gynoecious lines is instrumental in developing F1 hybrids with higher productivity. Protected cultivation in cucumber is largely facilitated by breeding gynoecious parthenocarpic lines. A large diversity is available within the genus Cucumis in different parts of Asia and Africa. There is a need to evaluate the entire gene pool for important biotic and abiotic stresses to meet future challenges. Extensive genetic studies need to be conducted for all the traits related to the yield and adaptability of the cucumber genotypes using the available germplasm available with different gene banks and natural diversity.
Article
Full-text available
Cultivated melon was domesticated from wild melons, which produce small fruits with non-edible fruit flesh. The increase in fruit flesh is one of the major domestication achievements in this species. In previous work, a quantitative trait locus (QTL) on chromosome 6 (paqt6.1) linked to fruit flesh content was detected in a cross between cultivated (“Piel de Sapo”, PS) and wild (Ames 24294, TRI) accessions. The QTL was introgressed into the PS background, generating the TRI_6-3 introgression line (IL) that confirmed the effects of paqt6.1. The primary objective of this work was to fine-map paqt6.1 as the first step for the map-based cloning. Two different approaches were carried out; however, the results were not consistent, precluding the fine mapping of paqt6.1. TRI_6-3 and other related ILs were genotyped by genotyping-by-sequencing, finding additional introgressions in other chromosomes. In an F2 population from TRI_6-3-x-PS, we found an epistatic interaction between paqt6.1 and another locus on chromosome 11. The interaction was verified in advanced populations, suggesting that the effects of paqt6.1 are conditioned by the allelic composition at another locus in chromosome 11. Both loci should have TRI alleles to reduce the flesh content in the PS background. The implications on the history of melon domestication are discussed.
Article
Full-text available
Luffa spp. (sponge gourd or ridge gourd) is an economically important vegetable crop widely cultivated in China, India and Southeast Asia. Here, we employed PacBio long‐read single molecule real‐time (SMRT) sequencing to perform de novo genome assemblies of two commonly cultivated Luffa species, L. acutangula and L. cylindrica. We obtained preliminary draft genomes of 734.6 Mb and 689.8 Mb with scaffold N50 of 786,130 and 578,616 bases for L. acutangula and L. cylindrica, respectively. We also applied long‐range Chicago and Hi‐C techniques to obtain the first chromosome‐scale whole genome assembly of L. acutangula. The final assembly contained 13 pseudomolecules, corresponding to the haploid chromosome number in Luffa spp. (1n = 13, 2n = 26). The sizes of the assembled Luffa genomes are approximately twice as large as the genome assemblies of related Cucurbitaceae. A large proportion of L. acutangula (62.17%; 456.69 Mb) and L. cylindrica (56.78%; 391.65 Mb) genome assemblies contained repetitive elements. Phylogenetic analyses revealed that the substantial accumulation of transposable elements likely contributed to the expansion of the Luffa genomes. We also investigated alternative splicing events in Luffa using full‐length transcript sequences obtained from PacBio Isoform Sequencing (Iso‐seq). While the predominant form of alternative splicing in most plant species examined was intron retention, alternative 3’ acceptor site selection appeared to be a major event observed in Luffa. High‐quality genome assemblies for L. acutangula and L. cylindrica reported here provide valuable resources for Luffa breeding and future genetics and comparative genomics studies in Cucurbitaceae.
Article
Full-text available
Micronutrient malnutrition is a major problem in developing countries affecting women, children and infants. Biofortification, improved soil health and waste management efficiencies have been used to overcome nutrient deficiencies. Application of classical breeding and selection resulted in rapid development of staple crops through breeding. The Cucurbitaceae mainly pumpkins and squashes (Cucurbita moschata Duch., Cucurbita pepo L., Cucurbita maxima Duch. ex Lam), cucumber (Cucumis sativus L.), watermelon (Citrullus lanatus L.), and melon (Cucumis melo L.) possess beneficial vitamins and minerals that can be used as nutrients for human consumption. To improve nutritional content in Cucurbitaceae, understanding the information in the genome is important for breeders to increase the level of nutrition and quality of characteristics using biotechnology approaches. Nonconventional breeding approaches can assist conventional breeding to save time, costs, and efficacy in selection. This review describes breeding strategies for necessary solutions toward development of elite varieties of Cucurbitaceae via various approaches that contain high nutrition content and improve traits and quality to fight micronutrient malnutrition.
Article
Full-text available
Metal-tolerance proteins (MTPs) are divalent cation transporters and play fundamental roles in plant metal tolerance and ion homeostasis. Despite that, a systematic investigation of MTPs in Cucurbitacea is still lacking. In this study, 142 MTPs were identified from 11 released genomes of 8 Cucurbitaceae species. They were phylogenetically separated into three clusters (Zn-cation diffusion facilitator proteins [CDFs], Fe/Zn-CDFs, and Mn-CDFs) and further subdivided into seven groups (G1, G5, G6, G7, G8, G9, and G12). Characterization analysis revealed that most MTPs were plasma membrane-located hydrophobic proteins. Motif and exon/intron analysis showed that members in the same group contained similar conserved motifs and gene structures. Moreover, 98 pairs of segmental-like duplication events were found. The nonsynonymous/synonymous substitution ratios between each pair were less than 1, implying that Cucurbitaceae MTPs were under purification selection. Expression profiling suggested that several MTP genes, such as CsCLMTP1, CmeMTP3, LsMTP3, and Cl97103MTP3, were constitutively expressed in corresponding Cucurbitaceae species, and their expression levels were not significantly altered by NaCl, drought, or pathogen infection. The expression patterns of cucumber MTP genes under Zn2+ , Cu2+ , Mn2+ , and Cd2+ stress were studied by quantitative real-time polymerase chain reaction and the results showed that these MTPs were induced by at least one metal ion, suggesting their involvement in metal tolerance or transportation. The identification and comprehensive investigation of MTP family members will provide a basis for the analysis of ion transport functions and ion tolerance mechanisms of Cucurbitaceae MTPs.
Article
Full-text available
The structure of the thoracic epipodites on the stomatopod Hemisquilla ensigera (Owen) suggests that the primary function of these structures is respiratory. The presence of respiratory structures on the thoracic somites, coupled with other already published evidence links the hoplocarids and the other eumalacostracans to a common phyllocarid ancestor and argues against a polyphyletic origin for the Eumalacostraca.
Article
Full-text available
Depending on taxonomic concept, the genus Dactyliandra (Cucurbitaceae) comprises up to four species: two from Southwest Africa, D. luederitziana (Namibia) and D. welwitschii (Angola), and two very locally distributed and poorly known taxa from Northeast Africa, D. nigrescens and D. stefaninii. In addition to these African populations, D. welwitschii was also reported as a possibly native species from the Thar desert of Northwestern India and Pakistan ca. 8,000 km away from the Namib range. A phylogenetic analysis of plastid and nuclear ribosomal ITS DNA sequences including all Dactyliandra species and D. welwitschii from the Thar desert revealed that this striking disjunction is of very recent origin. Dactyliandra is monophyletic only after exclusion of the East African taxa, which are best placed in Trochomeria. The species Dactyliandra welwitschii is monophyletic and includes the Indian plants, which group with a sample from an Angolan population. We hypothesize that this unexpected connection is a result of man-mediated introduction to India from Africa perhaps in the times of the slave trade. The new combinations Blastania lucorum and Trochomeria nigrescens are published here.
Article
Full-text available
Type specimens are permanently preserved biological specimens that fix the usage of species names. This method became widespread from 1935 onwards and is now obligatory.We used DNA sequencing of types and more recent collections of wild and cultivated melons to reconstruct the evolutionary history of the genus Citrullus and the correct names for its species.We discovered that the type specimen of the name Citrullus lanatus, prepared by a Linnaean collector in South Africa in 1773, is not the species now thought of as watermelon. Instead, it is a representative of another species that is sister to C. ecirrhosus, a tendril-less South African endemic. The closest relative of the watermelon instead is a West African species. Our nuclear and plastid data furthermore reveal that there are seven species of Citrullus, not four as assumed.Our study implies that sweet watermelon originates from West, not southern Africa as previously believed, and that the South African citron melon has been independently domesticated. These findings affect and explain numerous studies on the origin of these two crops that led to contradictory results because of the erroneous merging of several distinct species.
Article
Full-text available
identical to print version). TAXON 63 (4) • August 2014: 941–942 Renner & al. • (2313) Conserve Momordica lanata (2313) Proposal to conserve the name Momordica lanata (Citrullus lanatus) (watermelon, Cucurbitaceae), with a conserved type, against Citrullus battich. rej. prop. Typus non designatus. This proposal originated as a spinoff of new results of DNA sequencing in the genus Citrullus, which put the currently accepted name for the sweet watermelon in jeopardy. While it was being drafted, a second threat to that name surfaced, which is also being taken into account. The watermelon was first validly named by Linnaeus (Sp. Pl.: 1010. 1753) as Cucurbita citrullus L. That name has not as yet been typified effectively (see details in Jarvis, Order Out of Chaos: 465. 2007). According to Jarvis the original material comprises two ele-ments, an illustration (Bauhin & al., Hist. Pl. 2: fig. on p. 236. 1651) and a specimen in the Burser Herbarium. However, the illustration is not an original element. Linnaeus's protologue reference is to Citrul-lus folio colocynthidis secto, semine nigro, on page 235 of Bauhin & al.'s work, where that plant is indeed described but not figured. The figure on the following page (236) is of Gitruli [sic] genus aliud (a different kind), which is described in the text as Citruli genus majus (a larger kind), differing in a number of features of the fruit and seed. Therefore a single original element remains: the specimen of "Anguria Citrullus dicta" in herb. Burser VII: 101 (UPS), that we here formally designate as the (obligate) lectotype. Savage (C. Lin-naei Det. Hort. Sicc. J. Burseri: 57. 1937) confirms that the specimen was examined and identified by Linnaeus before 1753. It is indeed a flowering shoot of the watermelon, as we could verify on the digital images kindly put at our disposal by Mats Hjertson. The nomenclatural history of the watermelon is chequered. For about a century (mid-19th to mid-20th) the name Citrullus vulgaris was in general use for it. However, already in 1930 Bailey (in Gentes Herbarum 2: 180–186) pointed out that "the methods of nomenclature must be liberally interpreted in this case, unless one is willing to adopt the doublet Citrullus Citrullus, and even this double name may not be without doubt". Such doubts were appropriate both at the genus and species level. Ahead of the 1950 Stockholm Congress, Hara proposed conser-vation of Citrullus Forssk. 1775 against two earlier synonyms, Anguria Mill. 1754 and Colocynthis Ludw. 1757, all said to refer to the water-melon. A corresponding preliminary entry appears in the Stockholm Code (Lanjouw & al. in Regnum Veg. 3: 137. 1952). Fosberg (in Taxon 2: 99–101. 1953), having been assigned the proposal for examination, supported it in principle but concluded that Citrullus Forssk., having been proposed without generic description for a genus comprising three species, was not a validly published name. Fosberg therefore suggested that Citrullus be conserved from its publication by Schrader in 1836, with C. vulgaris Schrad. (≡ Cucurbita citrullus L.) as its listed type; and that Citrullus Neck. 1790 be added to the entry as a rejected earlier homonym. This was approved and is what appears in the Paris Code (Lanjouw & al. in Regnum Veg. 8: 273. 1956). Since then, the only changes affecting the entry have been elimination of the Necker homonym (as Necker's generic names had been ruled not to be validly published) and replacement of Colocynthis Ludw. with the earlier, supposedly isonymous Colocynthis Mill. 1754 (Rickett & Stafleu in Taxon 9: 121. 1960). Hara (in Taxon 2: 134–135. 1953) had, in vain, objected to Fosberg's change to his proposal. Of Hara's two arguments, one is spurious (Cucurbita anguria Duchesne 1786 is an illegitimate name and cannot threaten Cucumis vulgaris), but the other is valid. "Though Forskål described three species under Citrullus, the first was the only for which he introduced a binomial … Forskål's Citrullus with only one validly published binomial … may be regarded as a monotypic genus." The Code at that time did not clearly define what a "monotypic genus" is, so both Fosberg's and Hara's interpretations were possible. When the definition eventually was given, first in Art. 42 Note 1 of the Sydney Code (Greuter & al. in Regnum Veg. 111: 39. 1983) and then in Art. 42.2 of the Tokyo Code (Greuter & al. in Regnum Veg. 131: 52. 1994), it confirmed Hara's position. Citrullus Forssk. 1775 is a validly published name, heterotypic although synonymous with Citrullus Schrad., and therefore by implication (ICN Art. 14.10) rejected in favour of the latter as an earlier homonym. [Thanks to a last-minute fix, this is now made explicit in the Citrullus entry in App. III to the Melbourne Code, McNeill & al. in Regnum Veg. 157, in press.]
Article
Full-text available
Bottle gourd (Lagenaria siceraria) was one of the first domesticated plants, and the only one with a global distribution during pre-Columbian times. Although native to Africa, bottle gourd was in use by humans in east Asia, possibly as early as 11,000 y ago (BP) and in the Americas by 10,000 BP. Despite its utilitarian importance to diverse human populations, it remains unresolved how the bottle gourd came to be so widely distributed, and in particular how and when it arrived in the New World. A previous study using ancient DNA concluded that Paleoindians transported already domesticated gourds to the Americas from Asia when colonizing the New World [Erickson et al. (2005) Proc Natl Acad Sci USA 102(51):18315-18320]. However, this scenario requires the propagation of tropical-adapted bottle gourds across the Arctic. Here, we isolate 86,000 base pairs of plastid DNA from a geographically broad sample of archaeological and living bottle gourds. In contrast to the earlier results, we find that all pre-Columbian bottle gourds are most closely related to African gourds, not Asian gourds. Ocean-current drift modeling shows that wild African gourds could have simply floated across the Atlantic during the Late Pleistocene. Once they arrived in the New World, naturalized gourd populations likely became established in the Neotropics via dispersal by megafaunal mammals. These wild populations were domesticated in several distinct New World locales, most likely near established centers of food crop domestication.
Article
Full-text available
The circumscription of the five to eight species of Luffa, as well as their correct names, have long been problematic. Experts on the genus, most recently C. Heiser and C. Jeffrey, have disagreed on the number of species in the New World and the application of the name L. operculata, which in turn affected the names L. quinquefida and L. sepium. Heiser used classic biosystematic methods, including experimental crossing, to infer species boundaries, but neither researcher had today’s option of using DNA sequences for this purpose. We sequenced 51 accessions of Luffa, representing the geographic range of the genus and as much as possible topotypical or type material. Phylogenies from four non-coding plastid regions and the nuclear ribosomal DNA spacer region show that eight clades of specimens have geographicmorphological coherence. Heiser’s view that Luffa has three species in the New World is supported, and there are four species in tropical and subtropical Asia. Australia has an endemic species, differing from the Indian species with which it had long been lumped. Our vouchered ITS and plastid sequences from throughout species’ ranges are available in GenBank and can serve to identify Luffa material similar to standard DNA barcoding regions. We also provide new arguments for Heiser’s application of the name L. operculata to a South American species, countering Jeffrey’s arguments in favor of its use for a Central American species.
Article
Full-text available
Watermelon, Citrullus lanatus, is an important cucurbit crop grown throughout the world. Here we report a high-quality draft genome sequence of the east Asia watermelon cultivar 97103 (2n = 2× = 22) containing 23,440 predicted protein-coding genes. Comparative genomics analysis provided an evolutionary scenario for the origin of the 11 watermelon chromosomes derived from a 7-chromosome paleohexaploid eudicot ancestor. Resequencing of 20 watermelon accessions representing three different C. lanatus subspecies produced numerous haplotypes and identified the extent of genetic diversity and population structure of watermelon germplasm. Genomic regions that were preferentially selected during domestication were identified. Many disease-resistance genes were also found to be lost during domestication. In addition, integrative genomic and transcriptomic analyses yielded important insights into aspects of phloem-based vascular signaling in common between watermelon and cucumber and identified genes crucial to valuable fruit-quality traits, including sugar accumulation and citrulline metabolism.
Article
Full-text available
The Cucurbitaceae genus Austrobryonia, with four species endemic to Australia, is described, illustrated, and placed in a phylogenetic context based on molecular and morphological data. In the Flora of australia (Telford 1982), all four species were provisionally included in Mukia, but not formally described. Austrobryonia argillicola, A. centralis, A. micrantha and A. pilbarensis are adapted to arid central regions of Australia. All species are known from 7-27 localities, and their distributional ranges are allopatric. A phylogenetic analysis of plastid and nuclear DNA sequences that included all four species in a family-wide context revealed that Austrobryonia is the closest living relative to a Eurasian and Mediterranean clade consisting of Bryonia and Ecballium. An rbcL molecular clock, calibrated with Cucurbitaceae fossils, dates this rare biogeographic disjunction to minimally 42 my ago (with an error of ca +-25%), while the crown group of Austrobryonia may be about 8 my old.
Article
Full-text available
We analysed phylogenetic relationships in the order Cucurbitales using 14 DNA regions from the three plant genomes: the mitochondrial nad1 b/c intron and matR gene, the nuclear ribosomal 18S, ITS1-5.8S-ITS2, and 28S genes, and the plastid rbcL, matK, ndhF, atpB, trnL, trnL-trnF, rpl20-rps12, trnS-trnG and trnH-psbA genes, spacers, and introns. The dataset includes 664 ingroup species, representating all but two genera and over 25% of the ca. 2600 species in the order. Maximum likelihood analyses yielded mostly congruent topologies for the datasets from the three genomes. Relationships among the eight families of Cucurbitales were: (Apodanthaceae, Anisophylleaceae, (Cucurbitaceae, ((Coriariaceae, Corynocarpaceae), (Tetramelaceae, (Datiscaceae, Begoniaceae))))). Based on these molecular data and morphological data from the literature, we recircumscribe tribes and genera within Cucurbitaceae and present a more natural classification for this family. Our new system comprises 95 genera in 15 tribes, five of them new: Actinostemmateae, Indofevilleeae, Thladiantheae, Momordiceae, and Siraitieae. Formal naming requires 44 new combinations and two new names in Cucurbitaceae.
Article
Full-text available
The biogeographical history of several important vegetables is still unclear. In the gourd family, Cucurbitaceae, this applies to melon and cucumber, but also to many species of more regional importance. Cucumeropsis mannii is cultivated in West Tropical Africa for its nutritious seeds. Family-wide phylogenetic analyses suggested that it is closest to Posadaea sphaerocarpa from Central and South America, the seeds of which are also eaten and the fruit of which is made into bowls. To reconstruct these species' historical biogeography, we sequenced six plastid markers and the nuclear ribosomal ITS region for several accessions of both species, plus all relevant outgroups. Morphological traits were studied in 102 herbarium specimens representing both species. A 5,155 nucleotide-long matrix of chloroplast and nuclear DNA contained a single informative mutation in a poly-C region of nuclear ITS among six accessions that covered the species' native ranges. Next-closest species differed in all plastid markers and by ≥34 mutations in ITS1 and ITS2. Study of the morphology revealed a possible small difference in fruit shape (cylindrical-ovate versus spherical), presumably resulting from human selection on the African populations. The closest outgroups Melancium and Melothria are endemic to the neotropics, and maximum likelihood area reconstruction indicates that Cucumeropsis mannii also originated there. The near-absence of genetic and morphological differentiation implies that gene flow between Cucumeropsis manni and Posadaea sphaerocarpa stopped relatively recently, and taxonomically they should (or could) be treated as one species. Transport of seeds during the transatlantic slave trade is a possible scenario, although we cannot reject natural dispersal.
Article
Full-text available
Molecular phylogenetic analyses based on numerous plant accessions have shown that Cucumis comprises 25 species in Asia, the Malesian region and Australia, rather than just two as traditionally thought. Among the 25 species several are new, and here we describe four from tropical Australia. The new species C. costatus, C. queenslandicus, C. umbellatus and C. variabilis are illustrated, their distributions mapped based on 7-50 collections per species and information is provided on habitats and conservation status. We also validate C. althaeoides comb. nov. and C. argenteus comb. nov., update the description of C. picrocarpus, and provide a key to the 11 native and naturalized species of Cucumis occurring in Australia and eastern Malesia.The Australian species diversity of Cucumis, a genus that until recently was held to be essentially African, is of interest also because Australia harhours the sister species to the commercially important melon, C. melo.
Article
Full-text available
We tested long-problematic generic boundaries in the tribe Sicyoeae and reconstructed the history of Sicyos using plastid and nuclear DNA sequences from 87 species (many with multiple acceassions) representing the group's generic and geographic diversity. Maximum likelihood and Bayesian approaches were used to infer relationships, divergent times, biogeographic history and ancestral traits. Thirteen smaller genera, including Sechium., are embedded in Sicyos, which when re-circumscribed as a monophyletic group comprises 75 species. The 14 Hawaiian species of Sicyos descended from a single ancestor that arrived c. 3 million years ago (Ma), Galapagos was reached twice at c. 4.5 and 1 Ma, the species in Australia descended from a single Neotropical ancestor (c. 2 Ma), and New Zealand was reached from Australia. Time since arrival thus does not correlate with Sicyos species numbers on the two archipelagos. A plausible mechanism for the four trans-Pacific dispersal events is adherence to birds of the tiny hard fruit with retrorsely barbed spines found in those lineages that underwent long-distance migrations. The Hawaiian clade has lost these spines, resulting in a lower dispersal ability compared with the Galapagos and Australian lineages, and perhaps favouring allopatric speciation.
Article
Full-text available
Morphometric data have long suggested the existence of three species of Sicyos in Australia and New Zealand. Molecular data now corroborate this and place the three species in the context of the remaining 72 species of Sicyos, most of them in the New World. We here describe and illustrate Sicyos undara I. Telford & P. Sebastian from northern Queensland and S. mawhai I. Telford & P. Sebastian from New Zealand, and emend the circumscription of S. australis to account for the removal of these two extraneous elements. We also provide a key to the three species, map their ranges, and note their habitat and conservation status.
Article
Full-text available
The Old World genus Trichosanthes has flowers with strikingly fringed petals, and Linnaeus therefore placed a species from Hispaniola that he only knew from an illustration (showing such fringed petals) in that genus. The species remained hidden from the attention of subsequent workers until acquiring new relevance in the context of molecular-biogeographic work on Cucurbitaceae. Based on molecular data, it is the sister to all Sicyeae, a New World clade of about 125 species in 16 genera. We here place this species in a new genus, Linnaeosicyos, describe and illustrate it, and discuss its phylogenetic context using molecular and morphological data. Judging from Dominican amber, elements of the flora of Hispaniola date back 15-20 my, and the occurrence on the island of at least five endemic species of Cucurbitaceae (Linnaeosicyos amara, Melothria domingensis, Sicana fragrans, and the sister species Anacaona sphaerica and Penelopeia suburceolata) points to its long occupation by Cucurbitaceae.
Article
Full-text available
Background The Cucurbitaceae genus Trichosanthes comprises 90–100 species that occur from India to Japan and southeast to Australia and Fiji. Most species have large white or pale yellow petals with conspicuously fringed margins, the fringes sometimes several cm long. Pollination is usually by hawkmoths. Previous molecular data for a small number of species suggested that a monophyletic Trichosanthes might include the Asian genera Gymnopetalum (four species, lacking long petal fringes) and Hodgsonia (two species with petals fringed). Here we test these groups’ relationships using a species sampling of c. 60% and 4759 nucleotides of nuclear and plastid DNA. To infer the time and direction of the geographic expansion of the Trichosanthes clade we employ molecular clock dating and statistical biogeographic reconstruction, and we also address the gain or loss of petal fringes. Results Trichosanthes is monophyletic as long as it includes Gymnopetalum, which itself is polyphyletic. The closest relative of Trichosanthes appears to be the sponge gourds, Luffa, while Hodgsonia is more distantly related. Of six morphology-based sections in Trichosanthes with more than one species, three are supported by the molecular results; two new sections appear warranted. Molecular dating and biogeographic analyses suggest an Oligocene origin of Trichosanthes in Eurasia or East Asia, followed by diversification and spread throughout the Malesian biogeographic region and into the Australian continent. Conclusions Long-fringed corollas evolved independently in Hodgsonia and Trichosanthes, followed by two losses in the latter coincident with shifts to other pollinators but not with long-distance dispersal events. Together with the Caribbean Linnaeosicyos, the Madagascan Ampelosicyos and the tropical African Telfairia, these cucurbit lineages represent an ideal system for more detailed studies of the evolution and function of petal fringes in plant-pollinator mutualisms.
Article
Full-text available
The bitter gourd genus Momordica comprises 47 species in Africa and 12 in Asia and Australia. All have unisexual flowers, and of the African species, 24 are dioecious, 23 monoecious, while all Asian species are dioecious. Maximum likelihood analyses of 6257 aligned nucleotides of plastid, mitochondrial and nuclear DNA obtained for 122 accessions of Momordica and seven outgroups show that Momordica is monophyletic and consists of 11 well-supported clades. Monoecy evolved from dioecy seven times independently, always in Africa and mostly in savanna species with low population densities. Leaky dioecy, with occasional fruit-producing males, occurs in two African species and might be the first step in an evolutionary transition towards monoecy. Dated biogeographic analyses suggest that Momordica originated in tropical Africa and that the Asian species are the result of one long-distance dispersal event about 19 million years ago. The pantropical vegetable Momordica charantia is of African, not Asian origin as had previously been suggested.
Article
Full-text available
Squash seeds, peduncles, and fruit rind fragments from Archaic period stratigraphic zones of Guilá Naquitz cave in Oaxaca, Mexico, are assigned to Cucurbita pepo on the basis of diagnostic morphological characters and identified as representing a domesticated plant on the basis of increased seed length and peduncle diameter, as well as changes in fruit shape and color, in comparison to wild Cucurbita gourds. Nine accelerator mass spectrometer radiocarbon dates on these specimens document the cultivation ofC. pepo by the inhabitants of Guilá Naquitz cave between 10,000 to 8000 calendar years ago (9000 to 7000 carbon-14 years before the present), which predates maize, beans, and other directly dated domesticates in the Americas by more than 4000 years.
Article
Full-text available
As a result of his botanical explorations in northern Australia, Ferdinand von Mueller named several Cucurbitaceae that molecular data now show to be distinct, requiring their resurrection from unjustified synonymy. We here describe and illustrate Luffa saccata F. Muell. ex I.Telford, validating a manuscript name listed under Luffa graveolens Roxb. since 1859, and we lectotypify Cucumis picrocarpus F. Muell. and Cucumis jucundus F. Muell. The lectotype of the name Cucumis jucundus, a synonym of Cucumis melo, is mounted on the same sheet as the lectotype of Cucumis picrocarpus, which is the sister species of the cultivated Cucumis melo as shown in a recent publication.
Article
Full-text available
Melon, Cucumis melo, and cucumber, C. sativus, are among the most widely cultivated crops worldwide. Cucumis, as traditionally conceived, is geographically centered in Africa, with C. sativus and C. hystrix thought to be the only Cucumis species in Asia. This taxonomy forms the basis for all ongoing Cucumis breeding and genomics efforts. We tested relationships among Cucumis and related genera based on DNA sequences from chloroplast gene, intron, and spacer regions (rbcL, matK, rpl20-rps12, trnL, and trnL-F), adding nuclear internal transcribed spacer sequences to resolve relationships within Cucumis. Analyses of combined chloroplast sequences (4,375 aligned nucleotides) for 123 of the 130 genera of Cucurbitaceae indicate that the genera Cucumella, Dicaelospermum, Mukia, Myrmecosicyos, and Oreosyce are embedded within Cucumis. Phylogenetic trees from nuclear sequences for these taxa are congruent, and the combined data yield a well-supported phylogeny. The nesting of the five genera in Cucumis greatly changes the natural geographic range of the genus, extending it throughout the Malesian region and into Australia. The closest relative of Cucumis is Muellerargia, with one species in Australia and Indonesia, the other in Madagascar. Cucumber and its sister species, C. hystrix, are nested among Australian, Malaysian, and Western Indian species placed in Mukia or Dicaelospermum and in one case not yet formally described. Cucumis melo is sister to this Australian/Asian clade, rather than being close to African species as previously thought. Molecular clocks indicate that the deepest divergences in Cucumis, including the split between C. melo and its Australian/Asian sister clade, go back to the mid-Eocene. Based on congruent nuclear and chloroplast phylogenies we conclude that Cucumis comprises an old Australian/Asian component that was heretofore unsuspected. Cucumis sativus evolved within this Australian/Asian clade and is phylogenetically far more distant from C. melo than implied by the current morphological classification.
Article
Full-text available
Conservatism in climatic tolerance may limit geographic range expansion and should enhance the effects of habitat fragmentation on population subdivision. Here we study the effects of historical climate change, and the associated habitat fragmentation, on diversification in the mostly sub-Saharan cucurbit genus Coccinia, which has 27 species in a broad range of biota from semi-arid habitats to mist forests. Species limits were inferred from morphology, and nuclear and plastid DNA sequence data, using multiple individuals for the widespread species. Climatic tolerances were assessed from the occurrences of 1189 geo-referenced collections and WorldClim variables. Nuclear and plastid gene trees included 35 or 65 accessions, representing up to 25 species. The data revealed four species groups, one in southern Africa, one in Central and West African rain forest, one widespread but absent from Central and West African rain forest, and one that occurs from East Africa to southern Africa. A few individuals are differently placed in the plastid and nuclear (LFY) trees or contain two ITS sequence types, indicating hybridization. A molecular clock suggests that the diversification of Coccinia began about 6.9 Ma ago, with most of the extant species diversity dating to the Pliocene. Ancestral biome reconstruction reveals six switches between semi-arid habitats, woodland, and forest, and members of several species pairs differ significantly in their tolerance of different precipitation regimes. The most surprising findings of this study are the frequent biome shifts (in a relatively small clade) over just 6 - 7 million years and the limited diversification during and since the Pleistocene. Pleistocene climate oscillations may have been too rapid or too shallow for full reproductive barriers to develop among fragmented populations of Coccinia, which would explain the apparently still ongoing hybridization between certain species. Steeper ecological gradients in East Africa and South Africa appear to have resulted in more advanced allopatric speciation there.
Article
Full-text available
Among the fundamental questions regarding cultivated plants is their geographic origin and region of domestication. The genus Cucumis, which includes cucumber (Cucumis sativus) and melon (Cucumis melo), has numerous wild African species, and it has therefore been assumed that melon originated in Africa. For cucumber, this seemed less likely because wild cucumbers exist in India and a closely related species lives in the Eastern Himalayas. Using DNA sequences from plastid and nuclear markers for some 100 Cucumis accessions from Africa, Australia, and Asia, we show here that melon and cucumber are of Asian origin and have numerous previously overlooked species-level relatives in Australia and around the Indian Ocean. The wild progenitor of C. melo occurs in India, and our data confirm that the Southeast Asian Cucumis hystrix is the closest relative of cucumber. Most surprisingly, the closest relative of melon is Cucumis picrocarpus from Australia. C. melo diverged from this Australian sister species approximately 3 Ma, and both diverged from the remaining Asian/Australian species approximately 10 Ma. The Asian/Australian Cucumis clade comprises at least 25 species, nine of them new to science, and diverged from its African relatives in the Miocene, approximately 12 Ma. Range reconstruction under maximum likelihood suggests Asia as the ancestral area for the most recent common ancestor of melon and cucumber, fitting with both having progenitor populations in the Himalayan region and high genetic diversity of C. melo landraces in India and China. Future investigations of wild species related to melon and cucumber should concentrate on Asia and Australia.
Article
Full-text available
Knowing the geographical origin of economically important plants is important for genetic improvement and conservation, but has been slowed by uneven geographical sampling where relatives occur in remote areas of difficult access. Less biased species sampling can be achieved when herbarium collections are included as DNA sources. Here, we address the history of Cucurbitaceae, one of the most economically important families of plants, using a multigene phylogeny for 114 of the 115 genera and 25 per cent of the 960 species. Worldwide sampling was achieved by using specimens from 30 herbaria. Results reveal an Asian origin of Cucurbitaceae in the Late Cretaceous, followed by the repeated spread of lineages into the African, American and Australian continents via transoceanic long-distance dispersal (LDD). North American cucurbits stem from at least seven range expansions of Central and South American lineages; Madagascar was colonized 13 times, always from Africa; Australia was reached 12 times, apparently always from Southeast Asia. Overall, Cucurbitaceae underwent at least 43 successful LDD events over the past 60Myr, which would translate into an average of seven LDDs every 10Myr. These and similar findings from other angiosperms stress the need for an increased tapping of museum collections to achieve extensive geographical sampling in plant phylogenetics.
Article
Full-text available
In unisexual flowers, sex is determined by the selective repression of growth or the abortion of either male or female reproductive organs. The mechanism by which this process is controlled in plants is still poorly understood. Because it is known that the identity of reproductive organs in plants is controlled by homeotic genes belonging to the MADS box gene family, we analyzed floral homeotic mutants from cucumber, a species that bears both male and female flowers on the same individual. To study the characteristics of sex determination in more detail, we produced mutants similar to class A and C homeotic mutants from well-characterized hermaphrodite species such as Arabidopsis by ectopically expressing and suppressing the cucumber gene CUCUMBER MADS1 (CUM1). The cucumber mutant green petals (gp) corresponds to the previously characterized B mutants from several species and appeared to be caused by a deletion of 15 amino acid residues in the coding region of the class B MADS box gene CUM26. These homeotic mutants reveal two important concepts that govern sex determination in cucumber. First, the arrest of either male or female organ development is dependent on their positions in the flower and is not associated with their sexual identity. Second, the data presented here strongly suggest that the class C homeotic function is required for the position-dependent arrest of reproductive organs.
Article
Full-text available
The origin of the Polynesian bottle gourd (Lagenaria siceraria), an important crop species in prehistoric Polynesia, has remained elusive. Most recently, a South American origin has been favored as the bottle gourd could have been introduced from this continent with the sweet potato by Polynesian voyagers around A.D. 1,000. To test the hypothesis of an American origin for the Polynesian bottle gourd, we developed seven markers specific to bottle gourd (two chloroplast and five nuclear). The nuclear markers were developed using a new technique where polymorphic inter simple sequence repeat (ISSR) markers are converted into single-locus polymerase chain reaction and sequencing markers--an approach that will be useful for developing markers in other taxa. All seven markers were sequenced in 36 cultivars of bottle gourd from Asia, the Americas, and Polynesia. The results support a dual origin for the Polynesian bottle gourd: the chloroplast markers are exclusively of Asian origin, but the nuclear markers show alleles originating in both the Americas and Asia. Because hybridization of Polynesian bottle gourds with post-European introductions cannot be excluded, ancient DNA from archaeological material will be useful for further elucidating the prehistoric movements of this species in Polynesia. This work has implications not only for the dispersal of the Polynesian bottle gourd but also for the domestication and dispersal of the species as a whole.
Article
Full-text available
Cucurbitaceae contain c. 800 species in 130 genera and are among the economically most important families of plants. We inferred their phylogeny based on chloroplast DNA sequences from two genes, one intron, and two spacers (rbcL, matK, trnL, trnL-trnF, rpl20-rps12) obtained for 171 species in 123 genera. Molecular data weakly support the traditional subfamilies Cucurbitoideae (111 genera) and Nhandiroboideae (19 genera, 60 species), and recover most of the eleven tribes, but almost none of the subtribes. Indofevillea khasiana is sister to all other Cucurbitoideae, and the genera of Joliffieae plus a few Trichosantheae form a grade near the base of Cucurbitoideae. A newly discovered large clade consists of the ancestrally Asian genera Nothoalsomitra, Luffa, Gymnopetalum, Hodgsonia, Trichosanthes, and the New World tribe Sicyeae. Genera that are poly- or paraphyletic include Ampelosicyos, Cucumis, Ibervillea, Neoachmandra, Psiguria, Trichosanthes, and Xerosicyos. Flower characters, especially number of free styles, fusion of filaments and/or anthers, tendril type, and pollen size, exine, and aperture number correlate well with the chloroplast phylogeny, while petal and fruit characters as well as karyotype exhibit much evolutionary flexibility.
Article
Descriptions and diagnoses are alternative choices in all Codes of Nomenclature because Linnaeus relied on diagnoses, not descriptions, to name ca. 13400 animals, plants, and fungi. A diagnosis names characters in which a new taxon differs from the most similar known taxon; a description mixes taxonomically informative and uninformative features, usually without indicating which is which. The first formal diagnoses of new taxa that included DNA-based characters came out in 2001, and by November 2015, at least 98 names of species of mites, acoels, lichens, angiosperms, annelids, alveolates, arachnids, centipedes, turtles, fishes, butterflies, mollusks, nematodes, and pathogenic fungi have been published based on diagnostic mitochondrial, plastid, or nuclear DNA substitutions, indels, or rarely genetic distances, with or without additional morphological features. Authors have found diverse ways to specify the diagnostic traits (all published studies are here tabulated). While descriptions try to 'cover' within-species variation, a goal rarely accomplished because of (i) the stochastic nature of specimen availability (thousands of species are known from single collections) and (ii) the subjective circumscription of species, the purpose of diagnoses was and is speedy identification. Linnaeus tried to achieve this by citing images, geographic occurrence, and previous literature. The renewed attention to sharp diagnosis now coincides with worldwide barcoding efforts, may speed up formal naming, and matches the increasing reliance on DNA for both classification and identification. I argue for DNA-based diagnoses of new species becoming a recommendation in all Codes, not just the bacterial code.
Article
In unisexual flowers, sex is determined by the selective repression of growth or the abortion of either male or female reproductive organs. The mechanism by which this process is controlled in plants is still poorly understood. Because it is known that the identity of reproductive organs in plants is controlled by homeotic genes belonging to the MADS box gene family, we analyzed floral homeotic mutants from cucumber, a species that bears both male and female flowers on the same individual. To study the characteristics of sex determination in more detail, we produced mutants similar to class A and C homeotic mutants from well-characterized hermaphrodite species such as Arabidopsis by ectopically expressing and suppressing the cucumber gene CUCUMBER MADS1 (CUM1). The cucumber mutant green petals (gp) corresponds to the previously characterized B mutants from several species and appeared to be caused by a deletion of 15 amino acid residues in the coding region of the class B MADS box gene CUM26. These homeotic mutants reveal two important concepts that govern sex determination in cucumber. First, the arrest of either male or female organ development is dependent on their positions in the flower and is not associated with their sexual identity. Second, the data presented here strongly suggest that the class C homeotic function is required for the position-dependent arrest of reproductive organs.
Article
The series of articles by Col. Sir Charles Close on A fifty-years retrospect continued from the previous volume right through 1933 and into 1934. This provides extensive human interest stories, and in particular the mention of Major Jervis is noted since he was at one time nominated as a possible Surveyor General of India in succession to Sir George Everest, but that did not materialise.
Article
Key message Comparative genetic mapping revealed the origin of Xishuangbanna cucumber through diversification selection after domestication. QTL mapping provided insights into the genetic basis of traits under diversification selection during crop evolution. Abstract The Xishuangbanna cucumber, Cucumis sativus L. var. xishuangbannanesis Qi et Yuan (XIS), is a semi-wild landrace from the tropical southwest China with some unique traits that are very useful for cucumber breeding, such as tolerance to low light, large fruit size, heavy fruit weight, and orange flesh color in mature fruits. In this study, using 124 recombinant inbred lines (RILs) derived from the cross of the XIS cucumber with a cultivated cucumber inbred line, we developed a linkage map with 269 microsatellite (or simple sequence repeat) markers which covered 705.9 cM in seven linkage groups. Comparative analysis of orders of common marker loci or marker-anchored draft genome scaffolds among the wild (C. sativus var. hardwickii), semi-wild, and cultivated cucumber genetic maps revealed that the XIS cucumber shares major chromosomal rearrangements in chromosomes 4, 5, and 7 between the wild and cultivated cucumbers suggesting that the XIS cucumber originated through diversifying selection after cucumber domestication. Several XIS-specific minor structural changes were identified in chromosomes 1 and 6. QTL mapping with the 124 RILs in four environments identified 13 QTLs for domestication and diversifying selection-related traits including 2 for first female flowering time (fft1.1, fft6.1), 5 for mature fruit length (fl1.1, fl3.1, fl4.1, fl6.1, and fl7.1), 3 for fruit diameter (fd1.1, fd4.1, and fd6.1), and 3 for fruit weight (fw2.1, fw4.1, and fw6.1). Six of the 12 QTLs were consistently detected in all four environments. Among the 13 QTLs, fft1.1, fl1.1, fl3.1, fl7.1, fd4.1, and fw6.1 were major-effect QTLs for respective traits with each explaining at least 10 % of the observed phenotypic variations. Results from this study provide insights into the cytological and genetic basis of crop evolution leading to the XIS cucumber. The molecular markers associated with the QTLs should be useful in exploring the XIS cucumber genetic resources for cucumber breeding.
Article
Medicinal uses of Bryonia (Cucurbitaceae) have been recorded for over two millennia, and even today there is a considerable market for Bryonia preparations in homeopathic medicine. The long use as a medicinal plant has led to anthropogenic range changes, followed by naturalization and invasiveness in disturbed habitats, for example, in the United States and New Zealand. Here we use phylogenetic and phylogeographic analyses of chloroplast and nuclear sequences to infer the major evolutionary units within Bryonia as well as their geographic history. Major clades in the gene trees fit with morphological differences and probably define ten biological species. Five species are endemic in the Irano-Turanian region, which also harbors the greatest chloroplast and nuclear haplotype diversity. Eurasia north of the southern permafrost border during the last glacial maximum has low species and haplotype diversity, fitting with relatively recent recolonization. The provenience of the B. alba genotype introduced to the United States could not be narrowed down; the B. dioica introduced to New Zealand and Georgia came from north-central, not southwestern Europe. In spite of anthropogenic range changes, Bryonia chloroplast haplotypes show a clear geographic pattern, and the role of interspecific hybridization appears to have been limited.
Article
Molecular phylogenetic analyses based on numerous plant accessions have shown that Cucumis comprises 25 species in Asia, the Malesian region, and Australia, rather than just two as traditionally thought. Among the 25 species several are new, and here we describe four from tropical Australia. The new species C. costatus, C. queenslandicus, C. umbellatus, and C. variabilis are illustrated, their distributions are mapped based on 7–50 collections per species, and information is provided on habitats and conservation status. We also validate C. althaeoides comb. nov. and C. argenteus comb. nov., update the description of C. picrocarpus, and provide a key to the 11 native and naturalized species of Cucumis occurring in Australia and eastern Malesia. The Australasian species diversity of Cucumis, a genus that until recently was held to be essentially African, is of interest also because Australia harbours the sister species to the commercially important melon, C. melo.
Article
Floral structure, including morphology, anatomy and histology, was comparatively studied in representatives of all seven families of Cucurbitales as currently circumscribed by other authors based on molecular analyses and including Corynocarpaceae, Coriariaceae, Tetramelaceae, Datiscaceae, Begoniaceae, Cucurbitaceae and Anisophylleaceae. Three superfamilial clades are supported by floral structure: Tetramelaceae/Datiscaceae, Tetramelaceae/Datiscaceae/Begoniaceae and Corynocarpaceae/Coriariaceae. Anisophylleaceae appear most isolated in Cucurbitales, and show more similarities with Oxalidales, especially Cunoniaceae, although some features of interest are shared with other Cucurbitales and not Oxalidales. Tetramelaceae and Datiscaceae share dioecy, completely isomerous (but not regularly pentamerous) flowers (not in male Datiscaceae), only small sepals, lacking petals (not in male Octomeles). Tetramelaceae, Datiscaceae and Begoniaceae share the presence of numerous small ovules and seeds with a large-celled surface, 2-cell-layered integuments, and a collar around the funicle by an extension of the outer integument. Corynocarpaceae and Coriariaceae share thick petals, unifacial stigmas, superior ovaries with a single, median, pendant syntropous ovule per carpel, and annular outer integuments with vasculature at the base. The four classical core families of Cucurbitales: Tetramelaceae, Datiscaceae, Begoniaceae and Cucurbitaceae (relationship unresolved, not retrieved as a clade as yet in molecular studies) share in various combinations androdioecy, basifixed and extrorse or latrorse anthers, trimerous gynoecia, bifurcate free carpel parts, an extended roof over the ovary formed by the ventral parts of the carpels, and parietal placentae. Trends of interest at the order level are unisexual flowers, thick, pointed petals (if present) that do not conform to the model in other rosids or basal core eudicots, a 2-cell-layered  inner  integument,  which  is  delayed  in  development,  and  lacking  or  scant  tanniferous  tissues  in flowers. © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society, 2004, 145, 129–185.
Article
Progress in studies of Cucurbitaceae since 1964 is reviewed, particular attention being paid to the roles of seed-coat anatomy, palynology and phytochemistry in elucidating the taxonomy of the family; to the use of wild species and land-races as sources of horticulturally desirable traits for the improvement of crops; to the potentialities of wild species for domestication as new crops for tropical areas, and to the biology of reproduction, sex control and sex expression. The classification of the lady is outlined, illustrated by discussion of the more important members of each tribe, and a revised classification ofCucumis is presented.
Article
Unlabelled: Premise of the study: The Cucurbitaceae genus Cayaponia comprises ∼60 species that occur from Uruguay to the southern United States and the Caribbean; C. africana occurs in West Africa and on Madagascar. Pollination is by bees or bats, raising the question of the evolutionary direction and frequency of pollinator shifts. Studies that investigated such shifts in other clades have suggested that bat pollination might be an evolutionary end point. • Methods: Plastid and nuclear DNA sequences were obtained for 50 accessions representing 30 species of Cayaponia and close relatives, and analyses were carried out to test monophyly, infer divergence times, and reconstruct ancestral states for habitat preferences and pollination modes. • Key results: The phylogeny shows that Cayaponia is monophyletic as long as Selysia (a genus with four species from Central and South America) is included. The required nomenclatural transfers are made in this paper. African and Madagascan accessions of C. africana form a clade that is part of a polytomy with Caribbean and South American species, and the inferred divergence time of 2-5 Ma implies a transoceanic dispersal event from the New World to Africa. The ancestral state reconstructions suggest that Cayaponia originated in tropical forests from where open savannas were reached several times and that bee pollination arose from bat pollination, roughly concomitant with the shifts from forests to savanna habitats. • Conclusions: Cayaponia provides the first example of evolutionary transitions from bat to bee pollination as well as another instance of transoceanic dispersal from the New World to Africa.
Article
A fossil flora was collected in situ from early Miocene deposits at site R117 in the Hiwegi Formation of Rusinga Island contemporaneous with and in close proximity to the sites from where the anthropoid primates were recovered. The flora exhibits a spatially and temporally patchy distribution of fruits and seeds, mixed with twigs of various sizes, fragments of wood, bark, and leaves, all with random orientations and very low depositional dips. There has been minimal transport and the flora evidently accumulated as in situ litter beneath local vegetation. Based on Nearest Living Relatives (NLR) of fruits and seeds, the vegetation represented is a deciduous broad-leaved woodland with continuous canopy, with trees, shrubs, lianas, and climbers, reminiscent of the structure of the modern vegetation in the steep-sided protected valleys in the Laetoli-Endulen area. The interpretation of the vegetation is supported by the presence of twigs, wood, and bark fragments from larger diameter axes. Climbers are represented by twining stem fragments as well as by a wide variety of distinctive fruits and seeds. The proportion of fossilised thorny twigs represents only 3% of the twig collections, and there are no unequivocal forest trees amongst the NLR. No grasses were present; monocotyledons are only represented by a single date palm stone. No conifer seeds or cones have been recovered, and there are no coniferous leafy shoots.
Article
The Cucurbitales are a clade of rosids with a worldwide distribution and a striking heterogeneity in species diversity among its seven family members: the Anisophylleaceae (29-40 species), Begoniaceae (1400 spp.), Coriariaceae (15 spp.), Corynocarpaceae (6 spp.), Cucurbitaceae (800 spp.), Datiscaceae (2 spp.), and Tetramelaceae (2 spp.). Most Cucurbitales have unisexual flowers, and species are monoecious, dioecious, andromonoecious, or androdioecious. To resolve interfamilial relationships within the order and to polarize morphological character evolution, especially of flower sexual systems, we sequenced nine plastids (atpB, matK, ndhF, rbcL, the trnL-F region, and the rpl20-rps12 spacer), nuclear (18S and 26S rDNA), and mitochondrial (nad1 b/c intron) genes (together approximately 12,000 bp) of 26 representatives of the seven families plus eight outgroup taxa from six other orders of the Eurosids I. Cucurbitales are strongly supported as monophyletic and are closest to Fagales, albeit with moderate support; both together are sister to Rosales. The deepest split in the Cucurbitales is that between the Anisophylleaceae and the remaining families; next is a clade of Corynocarpaceae and Coriariaceae, followed by Cucurbitaceae, which are sister to a clade of Begoniaceae, Datiscaceae, and Tetramelaceae. Based on this topology, stipulate leaves, inferior ovaries, parietal placentation, and one-seeded fruits are inferred as ancestral in Cucurbitales; exstipulate leaves, superior ovaries, apical placentation, and many-seeded fruits evolved within the order. Bisexual flowers are reconstructed as ancestral, but dioecy appears to have evolved already in the common ancestor of Begoniaceae, Cucurbitaceae, Datiscaceae, and Tetramelaceae, and then to have been lost repeatedly in Begoniaceae and Cucurbitaceae. Both instances of androdioecy (Datisca glomerata and Schizopepon bryoniifolius) evolved from dioecious ancestors, corroborating recent hypotheses about androdioecy often evolving from dioecy.
Article
The early development of agriculture in the New World has been assumed to involve early farming in settlements in the Andes, but the record has been sparse. Peanut (Arachis sp.), squash (Cucurbita moschata), and cotton (Gossypium barbadense) macrofossils were excavated from archaeological sites on the western slopes of the northern Peruvian Andes. Direct radiocarbon dating indicated that these plants grew between 9240 and 5500 14C years before the present. These and other plants were recovered from multiple locations in a tropical dry forest valley, including household clusters, permanent architectural structures, garden plots, irrigation canals, hoes, and storage structures. These data provide evidence for early use of peanut and squash in the human diet and of cotton for industrial purposes and indicate that horticultural economies in parts of the Andes took root by about 10,000 years ago.
Families and genera of flowering plants
  • H Schaefer
  • S S Renner
  • Cucurbitaceae
Schaefer H, Renner SS. Cucurbitaceae. In: Kubitzki K, editor. Families and genera of flowering plants, vol. 10. Berlin: Springer; 2011a. p. 112-74.
Cucumber and melon have their wild progenitors in India, and the sister species of Cucumis melo is from Australia
  • P M Sebastian
  • H Schaefer
  • Irh Telford
  • S S Renner
  • PM Sebastian
Sebastian PM, Schaefer H, Telford IRH, Renner SS. Cucumber and melon have their wild progenitors in India, and the sister species of Cucumis melo is from Australia. Proc Natl Acad Sci U S A. 2010;107(32):14269-73.
Mioz ä ne Floren des Bezirks Tambov
  • P I Dorofeev
Dorofeev PI. Mioz ä ne Floren des Bezirks Tambov. Akademija Nauka SSSR, Leningrad, Russian Academy of Sciences, USSR; 1988.
Allgemeine medizinisch-pharmazeutische Flora
  • V F Kosteletzky
  • VF Kosteletzky
Kosteletzky VF. Allgemeine medizinisch-pharmazeutische Flora, vol. 6. Prag: Borrosch & Andre; 1833.
Outlines of Botany, including a general history of the vegetable kingdom in which plants are arranged according to the system of natural affinities
  • G T Burnett
  • GT Burnett
Radiation following long-distance dispersal: the contributions of time, opportunity, and diaspore morphology in
  • P Sebastian
  • H Schaefer
  • R Lira
  • Irh Telford
  • Ss Renner
Sebastian P, Schaefer H, Lira R, Telford IRH, Renner SS. Radiation following long-distance dispersal: the contributions of time, opportunity, and diaspore morphology in Sicyos (Cucurbitaceae). J Biogeogr. 2012;39:1427–38. doi:10.1111/j.1365-2699.2012.02695.x.
The draft genome of watermelon
  • S Guo
  • J Zhang
  • H Sun
  • J Salse
  • Wj Lucas
  • H Zhang
Morphological and molecular data reveal three rather than one species of
  • Irh Telford
  • P Sebastian
  • Pj De Lange
  • Jj Bruhl
  • Ss Renner
Phylogeography of the ancient Eurasian medicinal plant genus
  • Sm Volz
  • Ss Renner