Ilia Leitch

• BSc Botany and Zoology University of Bristol
• Senior Research Leader in Character Evolution at Royal Botanic Gardens, Kew

We present a genome assembly from an individual Calendula officinalis (the common marigold; Streptophyta; Magnoliopsida; Asterales; Asteraceae). The genome sequence has a total length of 1,215.20 megabases. Most of the 1 n assembly is scaffolded into 16 chromosomal pseudomolecules, suggesting the individual is an allotetraploid (2 n = 4 x = 32). Th...

We present a genome assembly from a specimen of Spergularia bocconei (Greek sea-spurrey; Streptophyta; Magnoliopsida; Caryophyllales; Caryophyllaceae). The genome sequence has a total length of 466.20 megabases. Most of the assembly is scaffolded into 18 chromosomal pseudomolecules suggesting the individual is an allotetraploid (2 n = 4 x = 36). Th...

We present a genome assembly from a specimen of stinging nettle, Urtica dioica (Streptophyta; Magnoliopsida; Rosales; Urticaceae). The genome sequence has a total length of 618.00 megabases. Most of the assembly is scaffolded into 13 chromosomal pseudomolecules, representing one subgenome of the tetraploid genome. The mitochondrial assembly was sub...

Repetitive DNA contributes significantly to plant genome size, adaptation, and evolution. However, little is understood about the transcription of repeats. This is addressed here in the plant green foxtail millet (Setaria viridis). First, we used RepeatExplorer2 to calculate the genome proportion (GP) of all repeat types and compared the GP of long...

Alopecurus aequalis is a winter annual or short-lived perennial bunchgrass which has in recent years emerged as the dominant agricultural weed of barley and wheat in certain regions of China and Japan, causing significant yield losses. Its robust tillering capacity and high fecundity, combined with the development of both target and non-target-site...

Experiments comparing diploids with polyploids and in single grassland sites show that nitrogen and/or phosphorus availability influences plant growth and community composition dependent on genome size; specifically, plants with larger genomes grow faster under nutrient enrichments relative to those with smaller genomes. However, it is unknown if t...

Two hypotheses have been used to explain the loss of plant diversity with nutrient addition. The nutrient identity hypothesis posits that biodiversity loss is due to a specific limiting nutrient, such as nitrogen (N) or phosphorus (P), while the niche dimension hypothesis posits that adding a larger number of limiting nutrients, regardless of their...

We present a genome assembly from an individual Medicago arabica (the spotted medick; Tracheophyta; Magnoliopsida; Fabales; Fabaceae). The genome sequence is 515.5 megabases in span. Most of the assembly is scaffolded into 8 chromosomal pseudomolecules. The mitochondrial and plastid genome assemblies have lengths of 324.47 kilobases and 125.07 kilo...

We present a genome assembly of a specimen of common vervain, Verbena officinalis (Streptophyta; Magnoliopsida; Lamiales; Verbenaceae). The genome sequence has a total length of 289.20 megabases. Most of the assembly is scaffolded into 7 chromosomal pseudomolecules. The mitochondrial and plastid genome assemblies have lengths of 495.81 kilobases an...

We present a genome assembly from an individual Sambucus nigra (the European elder; Streptophyta; Magnoliopsida; Dipsacales; Adoxaceae). The genome sequence has a total length of 11,813.70 megabases. Most of the assembly is scaffolded into 18 chromosomal pseudomolecules. The mitochondrial and plastid genome assemblies have lengths of 724.11 kilobas...

We present a genome assembly from an individual Agrostemma githago (the corn cockle; Tracheophyta; Magnoliopsida; Caryophyllales; Caryophyllaceae). The genome sequence has a total length of 1,735.0 megabases. Most of the assembly is scaffolded into 24 chromosomal pseudomolecules suggesting the individual is a tetraploid (2 n = 4 x = 48). The organe...

Alopecurus aequalis is a winter annual or short-lived perennial bunchgrass which has in recent years emerged as the dominant agricultural weed of barley and wheat in certain regions of China and Japan, causing significant yield losses. Its robust tillering capacity and high fecundity, combined with the development of both target and non-target-site...

Increasing genome size (GS) has been associated with slower rates of DNA replication and greater cellular nitrogen (N) and phosphorus demands. Despite most plant species having small genomes, the existence of larger GS species suggests that such costs may be negligible or represent benefits under certain conditions. Focussing on the widespread and...

Grasses are considered one of the most important angiosperm groups in economic terms. The Setaria sphacelata complex is an intriguing species with considerable variation in genome size (GS). It is currently being explored from a genomic perspective especially because of its great adaptability under winter periods. Repetitive DNA sequences are known...

We present a genome assembly from an individual Comarum palustre (the marsh cinquefoil; Streptophyta; Magnoliopsida; Rosales; Rosaceae). The genome sequence has a total length of 528.90 megabases. Most of the assembly is scaffolded into 21 chromosomal pseudomolecules suggesting the individual is an allohexaploid (2 n = 6 x = 42). The mitochondrial...

Male reproductive investment, in particular pollen production, is a crucial and ecologically relevant component of a plant’s phenotype and reproductive success. Its evolutionary trajectory, however, remains understudied, partly due to a lack of convenient methods to assess it. We developed a protocol for pollen quantification by flow cytometry and...

The daisy tribe Anthemideae Cass. is one of the largest and most diverse tribes within Asteraceae. We analyzed a data set including 61 out of 111 Anthemideae genera, and all but four of the 19 currently recognized subtribes (Inulantherinae, Lapidophorinae, Lonadinae, and Vogtiinae) using a targeted high-throughput sequencing approach, the first foc...

Angiosperms with large genomes experience nuclear‐, cellular‐, and organism‐level constraints that may limit their phenotypic plasticity and ecological niche, which could increase their risk of extinction. Therefore, we test the hypotheses that large‐genomed species are more likely to be threatened with extinction than those with small genomes, and...

Efficient use of nitrogen (N) and phosphorus (P) is essential to reduce fertilizer costs and nutrient pollution and to lower the carbon footprint of agriculture. This requires a better understanding of N and P limitations on photosynthesis and biomass generation in one of the world's most important crops, wheat (Triticum aestivum). In a fully facto...

The molecular underpinnings and consequences of cycles of whole-genome duplication (WGD) and subsequent gene loss through subgenome fractionation remain largely elusive. Endogenous drivers, such as transposable elements, have been postulated to shape genome-wide dominance and biased fractionation leading to a conserved least-fractionated (LF) and a...

The generation and analysis of genome-scale data—genomics—is driving a rapid increase in plant biodiversity knowledge. However, the speed and complexity of technological advance in genomics presents challenges for its widescale use in evolutionary and conservation biology. Here, we introduce and describe a national-scale collaboration conceived to...

Reconstructing evolutionary trajectories and transitions that have shaped floral diversity relies heavily on the phylogenetic framework on which traits are modelled. In this study, we focus on the angiosperm order Ranunculales, sister to all other eudicots, to unravel higher-level relationships, especially those tied to evolutionary transitions in...

Vascular plants are exceptional among eukaryotes due to their outstanding genome size diversity which ranges ∼2,400-fold, including the largest genome so far recorded in the angiosperm Paris japonica (148.89 Gbp/1C). Despite available data showing that giant genomes are restricted across the Tree of Life, the biological limits to genome size expans...

The baobab trees (genus Adansonia) have attracted tremendous attention because of their striking shape and distinctive relationships with fauna¹. These spectacular trees have also influenced human culture, inspiring innumerable arts, folklore and traditions. Here we sequenced genomes of all eight extant baobab species and argue that Madagascar shou...

We present a genome assembly from an individual Salicornia ramosissima (purple glasswort; Tracheophyta; Magnoliopsida; Caryophyllales; Chenopodiaceae). The genome sequence is 529.1 megabases in span. Most of the assembly is scaffolded into 9 chromosomal pseudomolecules. The mitochondrial and plastid genome assemblies have lengths of 328.55 kilobase...

Societal Impact Statement Research efforts in plant biology have often been focused on sequenced and well‐studied ‘model’ organisms. Despite the advent of relatively inexpensive genome sequencing, most plant taxonomic groups are underrepresented, with few species that ‘represent’ the diversity of whole genera. This study describes an economical gui...

Angiosperms are the cornerstone of most terrestrial ecosystems and human livelihoods1,2. A robust understanding of angiosperm evolution is required to explain their rise to ecological dominance. So far, the angiosperm tree of life has been determined primarily by means of analyses of the plastid genome3,4. Many studies have drawn on this foundation...

We present a genome assembly from an individual Trifolium dubium (lesser trefoil; Tracheophyta; Magnoliopsida; Fabales; Fabaceae) as part of a collaboration between the Darwin Tree of Life and the European Reference Genome Atlas. The genome sequence is 679.1 megabases in span. Most of the assembly is scaffolded into 15 chromosomal pseudomolecules....

We present a genome assembly from an individual Trifolium subterraneum (subterranean clover; Tracheophyta; Magnoliopsida; Fabales; Fabaceae). The genome sequence is 483.8 megabases in span. Most of the assembly is scaffolded into 8 chromosomal pseudomolecules. The mitochondrial and plastid genome assemblies have lengths of 309.28 kilobases and 144....

Abstract Background and Aims The geographical origin and evolutionary mechanisms underpinning the rich and distinctive New Caledonian flora remain poorly understood. This is attributable to the complex geological past of the island and to the scarcity of well-resolved species-level phylogenies. Here, we infer phylogenetic relationships and divergen...

We present a genome assembly from an individual Trifolium fragiferum (strawberry clover; Tracheophyta; Magnoliopsida; Fabales; Fabaceae). The genome sequence is 512.0 megabases in span. Most of the assembly is scaffolded into 8 chromosomal pseudomolecules. The mitochondrial and plastid genome assemblies have lengths of 298.57 kilobases and 139.15 k...

We present a genome assembly from an individual Scutellaria minor (Tracheophyta; Magnoliopsida; Lamiales; Lamiaceae). The genome sequence is 341.8 megabases in span. Most of the assembly is scaffolded into 14 chromosomal pseudomolecules. The mitochondrial and plastid genome assemblies have lengths of 376.64 kilobases and 152.59 kilobases in length,...

We present a genome assembly from an individual Chamaenerion angustifolium (fireweed; Tracheophyta; Magnoliopsida; Myrtales; Onagraceae). The genome sequence is 655.9 megabases in span. Most of the assembly is scaffolded into 18 chromosomal pseudomolecules. The mitochondrial and plastid genome assemblies have lengths of 495.18 kilobases and 160.41...

We present a genome assembly from an individual Medicago arabica (the spotted medick; Tracheophyta; Magnoliopsida; Fabales; Fabaceae). The genome sequence is 515.5 megabases in span. Most of the assembly is scaffolded into 8 chromosomal pseudomolecules. The mitochondrial and plastid genome assemblies have lengths of 324.47 kilobases and 125.07 kilo...

Orchids constitute one of the most spectacular radiations of flowering plants. However, their origin, spread across the globe, and hotspots of speciation remain uncertain due to the lack of an up‐to‐date phylogeographic analysis. We present a new Orchidaceae phylogeny based on combined high‐throughput and Sanger sequencing data, covering all five s...

Human factors and plant characteristics are important drivers of plant invasions, which threaten ecosystem integrity, biodiversity and human well-being. However, while previous studies often examined a limited number of factors or focused on a specific invasion stage (e.g., naturalization) for specific regions, a multi-factor and multi-stage analys...

Angiosperms, which inhabit diverse environments across all continents, exhibit significant variation in genome sizes, making them an excellent model system for examining hypotheses about the global distribution of genome size. These include the previously proposed large genome constraint, mutational hazard, polyploidy‐mediated, and climate‐mediated...

We present a genome assembly from a specimen of Potentilla anserina (the silverweed cinquefoil; Streptophyta; eudicotyledons; Rosales; Potentilleae). The haploid genome sequence is 237 megabases in span. Most of the assembly is scaffolded into seven chromosomal pseudomolecules. The mitochondrial and plastid genomes have also been assembled and are...

Model species continue to underpin groundbreaking plant science research. At the same time, the phylogenetic resolution of the land plant Tree of Life continues to improve. The intersection of these two research paths creates a unique opportunity to further extend the usefulness of model species across larger taxonomic groups. Here we promote the u...

We present a genome assembly from a specimen of Ballota nigra (black horehound; Tracheophyta; Magnoliopsida; Lamiales; Lamiaceae). The genome sequence is 1186.8 megabases in span. Most of the assembly is scaffolded into 11 chromosomal pseudomolecules. Three mitochondrial chromosomes were assembled, with lengths of 148,17, 121,67 and 125,74 kilobase...

Model species continue to underpin groundbreaking plant science research. At the same time, the phylogenetic resolution of the land plant Tree of Life continues to improve. The intersection of these two research paths creates a unique opportunity to further extend the usefulness of model species across larger taxonomic groups. Here we promote the u...

What grows where? Knowledge about where to find particular species in nature must have been key to the survival of humans throughout our evolution. Over time, and as people colonised new land masses and habitats, interactions with the local biota led to a wealth of combined traditional and scientific wisdom about the distributions of species and th...

Orchids constitute one of the most spectacular radiations of flowering plants. However, their geographical origin, historical spread across the globe, and hotspots of speciation remain uncertain due to the lack of a broad phylogenomic framework. ⍰ We present a new Orchidaceae phylogeny based on high-throughput and Sanger sequencing datasets, coveri...

Angiosperms with large genomes experience nuclear-, cellular- and organism-level constraints that may limit their phenotypic plasticity and ecological niche. These constraints have been documented to vary across lineages, life-history strategies, ecogeographic patterns and environmental conditions. Therefore, we test the hypotheses that extinction...

1) Angiosperms, which inhabit diverse environments across all continents, exhibit significant variation in genome sizes, making them an excellent model system for examining hypotheses about the global distribution of genome size. These include the previously proposed large-genome-constraint, mutational-hazard, polyploidy-mediated, and climate-media...

Genome size is a plant character with far-reaching implications, ranging from impacts on the financial and computing feasibility of sequencing and assembling genomes all the way to influencing the very ecology and evolution of species. The increasing recognition of the role of genome size in plant science has led to a rising demand for comprehensiv...

The vascular flora of Britain and Ireland is a historically well-documented and clearly delimited study system that offers itself to large-scale analyses of ecology and species assemblages. However, such analyses require clean, curated, and taxonomically resolved data, which are often unavailable. In this chapter, we describe how to access and use...

We present a genome assembly from a Juncus effusus (soft rush; Tracheophyta; Magnoliopsida; Poales; Juncaceae). The genome sequence is 242.9 megabases in span. Most of the assembly is scaffolded into 21 chromosomal pseudomolecules. The mitochondrial genome is 519.0 kilobases long, while the plastid genome is 175.1 kilobases long.

Angiosperm diversity arises from trait flexibility and repeated evolutionary radiations, but the role of genomic characters in these radiations remains unclear. In this opinion article, we discuss how genome size can influence angiosperm diversification via its intricate link with cell size, tissue packing, and physiological processes which, in tur...

We present a genome assembly from an individual Ailanthus altissima (tree of heaven; Streptophyta; Magnoliopsida; Sapindales; Simaroubaceae). The genome sequence is 939 megabases in span. Most of the assembly is scaffolded into 31 chromosomal pseudomolecules. The mitochondrial and plastid genome assemblies are 661.1 kilobases and 161.1 kilobases lo...

Karyological characteristics are among the traits underpinning the invasion success of vascular plants. Using 11 049 species, we tested the effects of genome size and ploidy levels on plant naturalization (species forming self‐sustaining populations where they are not native) and invasion (naturalized species spreading rapidly and having environmen...

Human assistance and species’ characteristics are among the key drivers of plant invasions, which profoundly threaten ecosystem integrity, biodiversity and human well-being. However, previous studies have typically focused on one or a few factors or a particular invasion stage (e.g., naturalization) at regional scales. Here, we employed a multileve...

Whole genome duplications (WGD) are frequent in many plant lineages; however, ploidy level variation is unknown in most species. The most widely used methods to estimate ploidy levels in plants are chromosome counts, which require living specimens, and flow cytometry estimates, which necessitate living or relatively recently collected samples. Newl...

Underutilised crops suffer from under-investigation relative to more mainstream crops, but often possess improved stress tolerance and/or nutrition, making them potentially important for breeding programmes in the context of climate change and an expanding human population. Developing basic genome resources for underutilised crops may therefore cat...

Angiosperm genome sizes (GS) range ~2400-fold and comprise genes and their regulatory regions, repeats, semi-degraded repeats, and 'dark matter'. The latter represents repeats so degraded that they can no longer be recognised as repetitive. In exploring whether the histone modifications associated with chromatin packaging of these contrasting genom...

Lichen-forming fungi are a diverse and ecologically important group of obligate mutualistic symbionts. Due to difficulties with maintaining them in culture and their extremely slow growth, lichenologists are increasingly opting for metagenomic sequencing followed by symbiont genome separation using bioinformatic pipelines. However, without knowing...

The importance of natural hybridization in the evolutionary process has intrigued biologists for decades. However, our general understanding of natural hybridization is impeded by the complex and often idiosyncratic outcomes of hybridization. Here, we investigate hybridization across all native flowering plant species in the intensely studied UK fl...

Sapindales is an angiosperm order of high economic and ecological value comprising nine families, c. 479 genera, and c. 6570 species. However, family and subfamily relationships in Sapindales remain unclear, making reconstruction of the order’s spatio-temporal and morphological evolution difficult. In this study, we used Angiosperms353 target captu...

The Ascomycota form the largest phylum in the fungal kingdom and show a wide diversity of lifestyles, some involving associations with plants. Genomic data is available for many ascomycetes that are pathogenic to plants, but endophytes, which are asymptomatic inhabitants of plants, are relatively understudied. Here, using short- and long-read techn...

Giant genomes are rare across the plant kingdom and their study has focused almostexclusively on angiosperms and gymnosperms. The scarce genetic data that are available for ferns,however, indicate differences in their genome organization and a lower dynamism compared toother plant groups. Tmesipteris is a small genus of mainly epiphytic ferns that...

Asteraceae, the daisy family, are one of the most diverse families of angiosperms and are predominant in many ecosystems, including grasslands, deserts, savannas and high-elevation mountains. They are characterized by a peculiar inflorescence, the capitulum, which mimics a flower, but is actually made up of many tightly grouped florets. The capitul...

Background and aims Among the numerous pantropical species of the yam genus, Dioscorea, only a small group occurs in the Mediterranean basin, including two narrow Pyrenean endemics (Borderea clade), and two Mediterranean-wide species (D. communis and D. orientalis, Tamus clade). However, several currently unrecognized species and infraspecific taxa...

We present genome assemblies from four Malus domestica cultivars (the apple; Streptophyta; Magnoliopsida; Rosales; Rosaceae). The genome sequences are 643–653 megabases in span. The greater part of each assembly length (99.24–99.74%) is scaffolded into 17 chromosomal pseudomolecules. The mitochondrial and plastid genomes were also assembled and are...

Background and aims. Among the numerous pantropical species of the yam genus, Dioscorea , only a small group occurs in the Mediterranean basin, including two narrow Pyrenean endemics (Borderea clade), and two Mediterranean-wide species ( D. communis and D. orientalis , Tamus clade). However, several currently unrecognized species and infraspecific...

Grassland ecosystems cover c. 40% of global land area and contain c. 40% of soil organic carbon. Understanding the effects of adding nutrients to grasslands is essential because they provide much of our food, support diverse ecosystem services and harbor rich biodiversity. Using the meadow steppe (grassland) study site of Inner Mongolia, we manipul...

The Andean fever tree (Cinchona L.; Rubiaceae) is a source of bioactive quinine alkaloids used to treat malaria. C. pubescens Vahl is a valuable cash crop within its native range in northwestern South America, however, genomic resources are lacking. Here we provide the first highly contiguous and annotated nuclear and plastid genome assemblies usin...

Protecting nature’s contributions to people requires accelerating extinction risk assessment and better integrating evolutionary, functional and used diversity with conservation planning. Here, we report machine learning extinction risk predictions for 1,381 palm species (Arecaceae), a plant family of high socio-economic and ecological importance....

Flow cytometry (FCM) is currently the most widely‐used method to establish nuclear DNA content in plants. Since simple, 1‐3‐parameter, flow cytometers, which are sufficient for most plant applications, are commercially available at a reasonable price, the number of laboratories equipped with these instruments, and consequently new FCM users, has gr...

Simple telomeric repeats composed of 6‐7 iterating nucleotide units are important sequences typically found at the ends of chromosomes. Here we analyzed their abundance and homogeneity in 42 gymnosperm (29 newly sequenced), 29 angiosperm (1 newly sequenced) and 8 bryophytes using bioinformatics, conventional cytogenetic and molecular biology approa...

Ecotypes are distinct populations within a species that are adapted to specific environmental conditions. Understanding how these ecotypes become established, and how they interact when reunited, is fundamental to elucidating how ecological adaptations are maintained. This study focuses on Themeda triandra, a dominant grassland species across Asia,...

A new study uncovers a novel trade-off in polyploid plants. While the larger cells of polyploids benefit from increased cell storage and water retention, this comes at the cost of reduced structural stability, potentially impacting survival.

With c. 24 700 species (10% of all flowering plants), Asteraceae are one of the largest and most phenotypically diverse angiosperm families, with considerable economic and ecological importance. Asteraceae are distributed worldwide, from nearly polar latitudes all the way to the tropics, and occur across a diverse range of habitats from extreme des...

Cytological data resources are crucial to the study and understanding of the evolution of complex taxa. Recent research on the genus Begonia L. has provided a robust phylogenetic background for the analysis of evolutionary patterns across the group and has established that Begonia is variable in genome size and chromosome number. This paper provide...

Genome size varies 2400‐fold across plants, influencing their evolution through changes in cell size and cell division rates which impact plants' environmental stress tolerance. Repetitive element expansion explains much genome size diversity, and the processes structuring repeat ‘communities’ are analogous to those structuring ecological communiti...

Reliably documenting plant diversity is necessary to protect and sustainably benefit from it. At the heart of this documentation lie species concepts and the practical methods used to delimit taxa. Here, we apply a total-evidence, iterative methodology to delimit and document species in the South American genus Victoria (Nymphaeaceae). The systemat...

Increased ecological disturbances, species invasions, and climate change are creating severe conservation problems for several plant species that are widespread and foundational. Understanding the genetic diversity of these species and how it relates to adaptation to these stressors are necessary for guiding conservation and restoration efforts. Th...

Polyploidy is a widespread phenomenon across angiosperms, and one of the main drivers of diversification. Whilst it frequently involves hybridisation, autopolyploidy is also an important feature of plant evolution. Minority cytotypes are frequently overlooked due to their lower frequency in populations, but the development of techniques such as flo...

Background The Andean fever tree ( Cinchona L.; Rubiaceae) is the iconic source of bioactive quinine alkaloids which have been key to treating malaria for centuries. In particular, C. pubescens Vahl has been an important source of income for several countries in its native range in north-western South America. However, the genomic resources require...

Gnetophytes are an enigmatic gymnosperm lineage comprising three genera, Gnetum, Welwitschia and Ephedra, which are morphologically distinct from all other seed plants. Their distinctiveness has triggered much debate as to their origin, evolution and phylogenetic placement among seed plants. To increase our understanding of the evolution of gnetoph...

The vascular flora of Britain and Ireland is among the most extensively studied in the world, but the current knowledge base is fragmentary, with taxonomic, ecological and genetic information scattered across different resources. Here we present the first comprehensive data repository of native and alien species optimized for fast and easy online a...

Social Impact Statement Climate change is expected to disproportionately affect sub‐Saharan Africa in the next century, posing a threat to the livelihoods of smallholder farmers and deepening food insecurity. To adapt to this threat, more climate‐resilient crops need to be brought into the food system; these may be developed through breeding with c...

Genome size varies 2,400-fold across plants, influencing their evolution through changes in cell size and cell division rates which impact plants’ environmental stress tolerance. Repetitive element expansion explains much genome size diversity, and the processes structuring repeat ‘communities’ are analogous to those structuring ecological communit...

[This corrects the article DOI: 10.3389/fgene.2021.726211.].