Amnon Levi

Amnon Levi
USDA, ARS, Charleston, South Carolina · U.S. Vegetable Laboratory,

Ph.D. in Plant Breeding and Genetics

About

214
Publications
57,164
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5,781
Citations
Citations since 2017
47 Research Items
3155 Citations
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20172018201920202021202220230100200300400500600
20172018201920202021202220230100200300400500600

Publications

Publications (214)
Article
of USA; Australian Butter (Australia); Marmellata and Marina di Chioggia of Italy contained the highest carotenoid content. EMMAX (Efficient Mixed-Model Association eXpedited) was employed for a Genome-wide association study (GWAS) to identify associated genomic regions underlying the regulation of carotenoids. Here, we profiled the contents of α-c...
Article
Full-text available
The genomic sequences segregating in experimental populations are often highly divergent from the community reference and from one another. Such divergence is problematic under various short-read-based genotyping strategies. In addition, large structural differences are often invisible despite being strong candidates for causal variation. These iss...
Article
Meloidogyne enterolobii is a virulent species of root-knot nematode that threatens watermelon (Citrullus lanatus) production in the southeast United States. There are no known sources of root-knot nematode resistance in cultivated C. lanatus. Specific genotypes of a wild watermelon relative, C. amarus, are resistant against Meloidogyne incognitaM....
Chapter
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Sweet watermelon (Citrullus lanatus var. vulgaris) belongs to the genus Citrullus Schrad and has six known species including Citrullus naudinianus, C. colocynthis, C. ecirrhosus, C. rehmii, C. amarus, and C. mucosospermus which exist in the wild. All these Citrullus spp. have wide variety of fruits with various shapes, size, rind thickness, colors...
Article
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The Cucurbitaceae (cucurbit) family consists of about 1,000 species in 95 genera, including many economically important and popular fruit and vegetable crops. During the past several years, reference genomes have been generated for >20 cucurbit species, and variome and transcriptome profiling data have been rapidly accumulated for cucurbits. To eff...
Article
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Since their introduction in Europe, pumpkins ( Cucurbita maxima Duch.) have rapidly dispersed throughout the world. This is mainly because of their wide genetic diversity and Plasticity to thrive in a wide range of geographical regions across the world, their high nutritional value and suitability to integrate with local cuisines, and their long sh...
Preprint
The genomic sequences segregating in experimental populations are often highly divergent from the community reference and from one another. Such divergence is problematic under various short-read-based genotyping strategies. In addition, large structural differences are often invisible despite being strong candidates for causal variation. These iss...
Article
Watermelon (Citrullus lanatus) is an important vegetable fruit crop, widely grown in many countries in the tropical and subtropical regions around the world. The narrow genetic base of cultivated watermelon makes it susceptible to many pests and diseases, especially viruses. However, genetic sources of resistance are available in wild relatives tha...
Article
Cultivated sweet watermelon (Citrullus lanatus) is an important vegetable crop for millions of people around the world. There are limited sources of resistance to economically important diseases within C. lanatus, whereas Citrullus amarus has a reservoir of traits that can be exploited to improve C. lanatus for resistance to biotic and abiotic stre...
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Background Watermelon seeds are a powerhouse of value-added traits such as proteins, free amino acids, vitamins, and essential minerals, offering a paleo-friendly dietary option. Despite the availability of substantial genetic variation, there is no sufficient information on the natural variation in seed-bound amino acids or proteins across the wat...
Preprint
Full-text available
Background Watermelon seeds are a powerhouse of value-added traits such as proteins, free amino acids, vitamins, and essential minerals, offering a paleo-friendly dietary option. Despite the availability of substantial genetic variation, there is no sufficient information on the natural variation in seed-bound amino acids or proteins across the wat...
Article
Full-text available
Sweet dessert watermelon (Citrullus lanatus) is one of the most important vegetable crops consumed throughout the world. The chemical composition of watermelon provides both high nutritional value and various health benefits. The present manuscript introduces a catalog of 1,679 small molecules occurring in the watermelon and their cheminformatics a...
Article
Polyploidy has played a crucial role in plant evolution, development, and function. Synthetic autopolyploid represents an ideal system to investigate the effects of polyploidization on transcriptional regulation. In this study, we deciphered the impact of genome duplication at phenotypic and molecular levels in watermelon. Overall, 88% of the genes...
Article
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Elemental sulfur is an effective, inexpensive fungicide for many foliar pathogens, but severe phytotoxicity prohibits its use on many melon varieties. Sulfur phytotoxicity causes chlorosis and necrosis of leaf tissue, leading to plant death in the most sensitive lines, while other varieties have little to no damage. A high-density, genotyping-by-se...
Article
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Root traits are an important component for productive plant performance. Roots offer immediate absorptive surfaces for water and nutrient acquisition and are thus critical to crop growth and response to biotic and abiotic stresses. In addition, roots can provide the first line of defense against soilborne pathogens. Watermelon crop performance is o...
Article
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Key message A Citrullus amarus mapping population segregating for resistance to Fusarium oxysporum f. sp. niveum race 2 and Papaya ringspot virus was used to identify novel QTL, important for the improvement in watermelon disease resistance. Abstract Multiple disease screens of the USDA Citrullus spp. germplasm collection have highlighted the valu...
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Key message Transcriptome landscape reveals the molecular mechanisms involved in the improvement of fruit traits by the grafting of watermelon and bottle gourd. Abstract Grafting has been used as a sustainable alternative for watermelon breeding to control soil-borne pathogens and to increase tolerance to various abiotic stresses. However, some rep...
Article
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Fruit characteristics of sweet watermelon are largely the result of human selection. Here we report an improved watermelon reference genome and whole-genome resequencing of 414 accessions representing all extant species in the Citrullus genus. Population genomic analyses reveal the evolutionary history of Citrullus, suggesting independent evolution...
Article
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Watermelon is a good source of citrulline, a non-protein amino acid. Citrulline has several therapeutic and clinical implications as it produces nitric oxide via arginine. In plants, citrulline plays a pivotal role in nitrogen transport and osmoprotection. The purpose of this study was to identify single nucleotide polymorphism (SNP) markers associ...
Article
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Key message Six QTLs were associated with affected leaf area in response to inoculation with Acidovorax citrulli in a recombinant inbred line population of Citrullus amarus. Abstract Acidovorax citrulli, the causal agent of bacterial fruit blotch (BFB) of cucurbits, has the potential to devastate production of watermelon and other cucurbits. Despi...
Article
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Color and pigment contents are important aspects of fruit quality and consumer acceptance of cucurbit crops. Here, we describe the independent mapping and cloning of a common causative APRR2 gene regulating pigment accumulation in melon and watermelon. We initially show that the APRR2 transcription factor is causative for the qualitative difference...
Article
Members of the highly polyphagous Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) species complex cause major crop damage by feeding and by transmitting plant viruses. The Middle East-Asia Minor 1 (MEAM1) of the B. tabaci complex is by far the most problematic whitefly affecting crops including cultivated watermelon (Citrullus lanatus; Cucurbit...
Article
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Years of selection for desirable fruit quality traits in dessert watermelon (Citrullus lanatus) has resulted in a narrow genetic base in modern cultivars. Development of novel genomic and genetic resources offers great potential to expand genetic diversity and improve important traits in watermelon. Here we report a high‐quality genome sequence of...
Preprint
Full-text available
Color and pigment content are important aspects of fruit quality and consumer acceptance of cucurbit crops. Here, we describe the independent mapping and cloning of a common causative APRR2 gene regulating pigment accumulation in melon and watermelon. We initially show that the APRR2 transcription factor is causative for the qualitative difference...
Article
Fusarium wilt race 1, caused by the soilborne fungus Fusarium oxysporum Schlechtend.: Fr. f. sp. niveum (E.F. Sm.) W.C. Snyder & H.N. Hans (Fon), is a major disease of watermelon (Citrullus lanatus) in the United States and throughout the world. Although Fusarium wilt race 1 resistance has been incorporated into several watermelon cultivars, identi...
Article
Full-text available
Fusarium wilt, caused by the fungus Fusarium oxysporum f. sp. niveum (Fon), is one of the predominant diseases of watermelon. Resistance to Fon race 1 is conferred by a single major quantitative trait locus (QTL), Fo-1.1, but resolution of this region has been poor due to low marker density. In this study, a combination of whole genome resequencing...
Article
Full-text available
The Cucurbitaceae family (cucurbit) includes several economically important crops, such as melon, cucumber, watermelon, pumpkin, squash and gourds. During the past several years, genomic and genetic data have been rapidly accumulated for cucurbits. To store, mine, analyze, integrate and disseminate these large-scale datasets and to provide a centra...
Article
Full-text available
Citrullus amarus (CA) (previously known as Citrullus lanatus var. citroides) accessions collected in southern Africa are known to have resistance to root-knot nematodes (RKN) and are suitable rootstocks for grafted watermelon. The objective of this study was to conduct a comparative metabolomics analysis and identify unique metabolites in roots of...
Article
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Key message: Four QTLs and an epistatic interaction were associated with disease severity in response to inoculation with Fusarium oxysporum f. sp. melonis race 1 in a recombinant inbred line population of melon. The USDA Cucumis melo inbred line, MR-1, harbors a wealth of alleles associated with resistance to several major diseases of melon, incl...
Article
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Originally from Africa, watermelon is a staple crop in South Carolina and rich source of important phytochemicals that promote human health. As a result of many years of domestication and selection for desired fruit quality, modern watermelon cultivars are susceptible to biotic and abiotic stress. The present review discusses how genetic selection...
Article
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The plant microbiome is a key determinant of plant health and productivity, and changes in the plant microbiome can alter the tolerance to biotic and abiotic stresses and the quality of end produce. Little is known about the microbial diversity and its effect on carbohydrate metabolism in ripe fruits. In this study, we aimed to understand the diver...
Article
A greenhouse trial was used to evaluate 159 accessions of bottle gourd [Lagenaria siceraria (Mol.) Standl.] obtained from the U.S. National Plant Germplasm for tolerance to clomazone herbicide. Most accessions tested were moderately or severely injured by clomazone at 3.0 mg·kg⁻¹ incorporated into greenhouse potting medium; however, several exhibit...
Article
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The common flesh color of commercially grown watermelon is red due to the accumulation of lycopene. However, natural variation in carotenoid composition that exists among heirloom and exotic accessions results in a wide spectrum of flesh colors. We previously identified a unique orange flesh watermelon accession (NY0016) that accumulates mainly β-c...
Article
How sugar transporters regulate sugar accumulation in fruits is poorly understood and particularly so for species storing high concentration sucrose. Accumulation of soluble sugars in watermelon (Citrullus lanatus) fruit, a major quality trait, had been selected during domestication. Still, the molecular mechanisms controlling this quantitative tra...
Article
Bottle gourd (Lagenaria siceraria) is an important vegetable crop as well as a rootstock for other cucurbit crops. In this study, we report a high-quality 313.4-Mb genome sequence of a bottle gourd inbred line, USVL1VR-Ls, with a scaffold N50 of 8.7 Mb and the longest of 19.0 Mb. About 98.3% of the assembled scaffolds are anchored to the 11 pseudom...
Chapter
Full-text available
As a result of many years of domestication and selection for desirable fruit quality, most of the modern dessert watermelon cultivars share a narrow genetic base. Africa is the center of origin and diversity of the genus Citrullus and is thus the focus of efforts to collect and conserve germplasm for enhancing dessert watermelons with resistance to...
Chapter
Full-text available
The genome size for watermelon (Citrullus lanatus), melon (Cucumis melo), cucumber (Cuucmis sativus) and pumpkin (Cucurbita pepo) is 425, 454, 367 and 502 Mbp, respectively, and considered medium size as compared with most other crops. Whole-genome duplication is common in angiosperm plants. Research has revealed a paleohexaploidy (ϒ) event in the...
Chapter
Full-text available
The genome size for watermelon (Citrullus lanatus), melon (Cucumis melo), cucumber (Cuucmis sativus) and pumpkin (Cucurbita pepo) is 425, 454, 367 and 502 Mbp, respectively, and considered medium size as compared with most other crops. Whole-genome duplication is common in angiosperm plants. Research has revealed a paleohexaploidy (ϒ) event in the...
Conference Paper
Nuclear magnetic resonance (NMR) was used to study the metabolic profiles of different watermelon lines and to highlight metabolic variation between several Citrullus lanatus var. citroides (CLC) accessions and Charleston Gray. Three days old plant roots were collected and analyzed using one-dimensional (1D) (1) H NMR spectroscopy. AMIX and MatLab...
Article
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Key message: A major QTL for resistance to Fusarium oxysporum f. sp. niveum race 2 was mapped to a narrow 1.2 Mb interval using a high-density GBS-SNP linkage map, the first map of Citrullus lanatus var. citroides. Fusarium wilt, a fungal disease caused by Fusarium oxysporum f. sp. niveum (Fon), devastates watermelon crop production worldwide. Sev...
Article
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Citrullus colocynthis (CC) is a viable source of genes for enhancing disease and pest resistance in common cultivated watermelon [Citrullus lanatus var. lanatus (CLL)] cultivars. However, there is little information about genetic diversity within CC or the relationship of CC accessions to C. lanatus. In this study, we examined genetic diversity and...
Article
Infection with Alternaria cucumerina causes Alternaria leaf blight (ALB), a disease characterized by lesion formation on leaves, leading to substantial yield and quality losses in Cucumis melo (melon). While fungicides are effective against ALB, reduction in the frequency of application would be economically and environmentally beneficial. Resistan...
Article
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When infecting a host plant, the fungus Fusarium oxysporum secretes several effector proteins into the xylem tissue to promote virulence. However, in a host plant with an innate immune system involving analogous resistance proteins, the fungus effector proteins may trigger resistance, rather than promoting virulence. Identity of the effector genes...
Article
Full-text available
Southern root-knot nematode (RKN, Meloidogyne incognita) is a serious pest of cultivated watermelon (Citrullus lanatus var. lanatus) in southern regions of the United States and no resistance is known to exist in commercial watermelon cultivars. Wild watermelon relatives (Citrullus lanatus var. citroides) have been shown in greenhouse studies to po...
Article
Full-text available
The bitter desert watermelon, Citrullus colocynthis (L.) Schrad is a wild species valuable for biotic and abiotic stress resistance that could be exploited for improving watermelon cultivars [Citrullus lanatus (Thunberg) Matsum & Nakai var. lanatus]. The objective of this study was to survey and identify C. colocynthis accessions displaying resista...
Article
Full-text available
Melon (Cucumis melo L.) is a phenotypically diverse eudicot diploid (2n = 2x =24) has climacteric and non-climacteric morphotypes and show wide variation for fruit firmness, an important trait for transportation and shelf life. We generated 13,789 SNP markers using genotyping-by-sequencing and anchored them to chromosomes to understand genome-wide...
Article
The inheritance of foreground stripe pattern in rind of watermelon fruits [Citrullus lanatus (Thunb.) Matsum. & Nakai] was evaluated and molecular markers for selecting the Jubilee-type (JT) stripe pattern were developed based on bulked segregant analysis (BSA). Divergence in rind pattern among F2 progeny derived from crossing Crimson-type (CT) ‘Ar...
Article
Full-text available
The response of Grapholita molesta (Busck) males to three-component sex pheromone blends containing a 100% ratio of the major sex pheromone component, (Z)-8-dodecenyl acetate and a 10% ratio of (Z)-8-dodecenol, but with varying ratios of (E)-8-dodecenyl acetate (0.4, 5.4, 10.4, 30.4, and 100.1% E-blends) was tested with populations in eight stone a...
Article
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Southern root-knot nematodes (Meloidogyne incognita) are an important re-emerging pest of watermelon in the United States and worldwide. The re-emergence of root-knot nematodes (RKNs) in watermelon and other cucurbits is largely the result of the intensive cultivation of vegetable crops on limited agricultural lands coupled with the loss of methyl...
Article
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Root-knot nematode-resistant rootstock lines (designated RKVL for Root-Knot Vegetable Laboratory) derived from wild watermelon (Citrullus lanatus var. citroides) were compared with wild tinda (Praecitrullus fistulosus) lines and commercial cucurbit rootstock cultivars for grafting of seedless triploid watermelon 'Tri-X 313' (C. lanatus var. lanatus...
Article
Selection for and incorporation of host plant resistance into cultivars is a fundamental strategy to control insects and diseases and may help reduce reliance on synthetic pesticides. The sweetpotato whitefly, Beinisia tabaci (Gennadius), is an important pest of watermelon [Citrullus lanatus (Thunberg) Matsum. and Nakai var. lanatus] and is among t...