Biology subjects

Schafleitner, R.

Publications and source records attributed to Schafleitner, R..

8 recordsLinked to original sources

bioRxiv2025

The demographic history, genomic variation, and transcontinental genotype-phenotype-environment map of mungbean

The breeding of mungbean, a crucial Asian legume, has been hampered by the lack of genomic resources. The International Mungbean Improvement Network (IMIN) aims to ensure global access to diverse germplasms and genomic resources. Using 780 worldwide wild and cultivated accessions, we report this species most comprehensive (pan)genomic variation, demographic history, and genotype-phenotype-environment map. Despite archaeological evidence of the earliest cultivation in South Asia, present-day wild populations only possess relict traces of shared polymorphisms with cultivars. We showed that parallel losses of black seed coats in two Vigna species were caused by the same mutational mechanism in the same gene. In large-scale cross-continent field trials, we found accessions from distant environments from the trial sites have lower performance, especially in high-heritability and high-yield sites, suggesting future breeding priority in benign conditions on accessions from similar environments. Our comprehensive genomic and trial resources facilitate future breeding success of this essential crop.

evolutionary biology↗

bioRxiv2024

Association analyses reveal both anthropic and environmental selective events during eggplant domestication

Eggplant (Solanum melongena) is one of the four most important Solanaceous crops, widely cultivated and consumed in Asia, the Mediterranean basin, and Southeast Europe. We studied the Genome-wide association (GWA) of historical genebank phenotypic data on a genotyped worldwide collection of 3,449 eggplant accessions. Overall, 334 significant associations for key agronomic traits were detected. Significant correlations were obtained between different types of phenotypic data, some of which were not obvious, such as between fruit size/yield and fruit color components, suggesting simultaneous anthropic selection for genetically unrelated traits. Anthropic selection of traits like leaf prickles, fruit color, and yield, acted on distinct genomic regions in the two domestication centers (India and Southeast Asia), further confirming the multiple domestication of eggplant. To discriminate anthropic from environmental selection in domestication centers, we conducted a Genotype-Environment Association (GEA) on a subset of georeferenced accessions from the Indian subcontinent. The population structure in this area revealed four genetic clusters, corresponding to a latitudinal gradient, and environmental factors explained 31% of the population structure when the effect of spatial distances was removed. GEA and outlier association (OA) identified 305 candidate regions under environmental selection, containing genes for abiotic stress responses, plant development, and flowering transition. Finally, in the Indian domestication center anthropic and environmental selection acted largely independently, and on different genomic regions. These data allow a better understanding of the different effects of environmental and anthropic selection during domestication of a crop, and the different world regions where some traits were initially selected by humans.

genomics↗

bioRxiv2022

Distinct selection signatures during domestication and improvement in crops: a tale of two genes in mungbean

Domestication and improvement are two crucial processes underlying the evolution of crops. Domestication transformed wild plants into a utilizable form for humans; improvement refined cultivars adapting to distinct environments and local preferences. Using whole-genome re-sequencing of Vigna radiata, we investigated the demographic history and compared the genetic footprints of domestication and improvement. The Asian wild population migrated to Australia at about 50 kya, and domestication happened in Asia about 9 kya selecting for non-shattering pods. The key candidate gene for this trait, VrMYB26a, has lower expression in cultivars, consistent with the reduced polymorphism in the promoter region reflecting hard selective sweep. The determinate stems were later selected as an improvement phenotype and associated with the gene VrDet1. Two ancient haplotypes reducing gene expression exhibit intermediate frequencies in cultivars, consistent with selection favoring independent haplotypes in soft selective sweep. Our results suggest domestication and improvement may leave different genomic signatures of selection, reflecting the fundamental differences in the two processes and highlighting the limitations of genome-scan methods relying on hard selective sweep.

plant biology↗

bioRxiv2022

The climatic constrains of the historical global spread of mungbean

While the domestication history has been investigated in many crops, the process of cultivation range expansion and factors governing this process received relatively little attention. Here using mungbean (Vigna radiata var. radiata) as a test case, we investigated the genomes of more than one thousand accessions to illustrate climatic adaptations role in dictating the unique routes of cultivation range expansion. Despite the geographical proximity between South and Central Asia, genetic evidence suggests mungbean cultivation first spread from South Asia to Southeast, East, and finally reached Central Asia. Combining evidence from demographic inference, climatic niche modeling, plant morphology, and records from ancient Chinese sources, we showed that the specific route was shaped by the unique combinations of climatic constraints and farmer practices across Asia, which imposed divergent selection favoring higher yield in the south but short-season and more drought-tolerant accessions in the north. Our results suggest that mungbean did not radiate from the domestication center as expected purely under human activity, but instead the spread of mungbean cultivation is highly constrained by climatic adaptation, echoing the idea that human commensals are more difficult to spread through the south-north axis of continents.

evolutionary biology↗

bioRxiv2021

De novo SNP calling reveals the candidate genes regulating days to flowering through interspecies GWAS of Amaranthus genus

Amaranths serve as pseudo cereals and also as traditional leafy vegetables worldwide. In addition to high vigor and richness in nutrients, drought and salinity tolerance of amaranth makes it a promising vegetable to acclimatize to the effects of global climate change. The World Vegetable Center genebank conserves about 1,000 amaranth accessions and various agronomic properties of these accessions were recorded during seed regeneration over decades. In this study, we verified the taxonomic annotation of the germplasm based on a 15K SNP set. Besides, in the assumption that the yield components of grain amaranths are different from those of leaf amaranths, we observed that grain amaranths presented larger inflorescences and earlier flowering than leaf amaranths. Dual-purpose amaranth showed larger leaves than leaf amaranths and later flowering than grain amaranths, which seemed reasonable because farmers can harvest more leaves during the prolonged vegetable stage, which also provides recovery time to enrich grain production. Considering frequent interspecies hybridization among grain amaranth complex, we proposed an interspecies GWAS for days to flowering, identifying a AGL20/SOC1 homolog. Meanwhile, another GWAS using only A. tricolor accessions revealed six candidate genes homologous to lba1, bri1, sgs1 and fca. These homologous genes were involved in the regulation of flowering time in Arabidopsis. This study revealed the usefulness of genotypes for species demarcation in the genus Amaranthus and the potential of interspecies GWAS to detect QTLs across different species, opening up the possibility of targeted introduction of specific genetic variants into different Amaranthus species.

genomics↗

bioRxiv2021

Population structure and association mapping for hundred seed weight in mungbean minicore

Mungbean is an important legume rich in protein and carbohydrates. It is cultivated mostly in south to south east Asia and east Africa. One of the important yield contributing traits in mungbean is 100 seed weight. Variation for this trait is available in the mungbean germplasm, and to facilitate improvement of this trait through breeding, genome-wide association mapping for 100 seed weight was carried out in the World Vegetable Center mungbean minicore collection. A total of 24,870 single nucleotide polymorphic markers were tested for association with 100 see weight in plants grown in Pakistan, Bangladesh, Myanmar and Taiwan and candidate loci associated with seed weight on chromosomes 1, 4, 6, 8 and 9 were identified. None of the QTLs was stable across all environments, but loci on chromosomes 4 and 8 were significant in Pakistan and Bangladesh and other loci on chromosome 8 were significantly associated in plants grown in Myanmar and Taiwan.

bioinformatics↗

bioRxiv2019

Long-read bitter gourd (Momordica charantia) genome and the genomic architecture of domestication

Bitter gourd (Momordica charantia) is a vegetable and medicinal plant of the family Cucurbitaceae. Here we report a chromosome-level assembly, with highest contig N50 (close to 10 Mb) and proportion of sequences placed on chromosomes (96%) in Cucurbitaceae. Population resequencing revealed the divergence between wild and cultivars at about 6000 years ago. Different cultivar groups have distinct allelic compositions in loci associated with domestication traits, suggesting phenotypic changes were achieved by allele frequency shifts in independent loci. Noticeably, one candidate locus for fruit size locates within a region missing from a recent Illumina-based assembly. Despite breeding efforts to increase female flower proportion, the gynoecy locus exhibits high variation within and low differentiation between wild and cultivar groups, likely because artificial directional selection could not overwhelm natural balancing selection. Our study provides resources to further investigate the genetic architecture of bitter gourd as well highlights the importance of a well-assembled genome.

genomics↗

bioRxiv2019

Understanding patterns of abiotic and biotic stress resilience to unleash the potential of crop wild relatives for climate-smart legume breeding

Although new varieties are urgently needed for climate-smart legume production, legume breeding lags behind with cereals and underutilizes wild relatives. This paper provides insights in patterns of abiotic and biotic stress resilience of legume crops and wild relatives to enhance the use and conservation of these genetic resources for climate-smart legume breeding. We focus on Vigna, a pantropical genus with more than 88 taxa including important crops such as cowpea and mung bean. Sources of pest and disease resistance occur in more than 50 percent of the Vigna taxa, which were screened while sources of abiotic stress resilience occur in less than 20 percent of the taxa, which were screened. This difference suggests that Vigna taxa co-evolve with pests and diseases while taxa are more conservative to adapt to climatic changes and salinization. Twenty-two Vigna taxa are poorly conserved in genebanks or not at all. This germplasm is not available for legume breeding and requires urgent germplasm collecting before these taxa extirpate on farm and in the wild. Vigna taxa, which tolerate heat and drought stress are rare compared with taxa, which escape these stresses or tolerate salinity. These rare Vigna taxa should be prioritized for conservation and screening for multifunctional traits of combined abiotic and biotic stress resilience. The high presence of salinity tolerance compared with drought stress tolerance, suggests that Vigna taxa are good at developing salt-tolerant traits compared with drought-tolerant traits. Vigna taxa are therefore of high value for legume production in areas that suffer from salinization.

plant biology↗