Riday, H. | bioRxiv Science

bioRxiv2023

A reference assembly for the legume cover crop, hairy vetch (Vicia villosa)

Vicia villosa is an incompletely domesticated annual legume of the Fabaceae family native to Europe and Western Asia. V. villosa is widely used as a cover crop and as a forage due to its ability to withstand harsh winters. A reference-quality genome assembly (Vvill1.0) was prepared from low error rate long sequence reads to improve genetic-based trait selection of this species. The Vvill1.0 assembly includes seven scaffolds corresponding to the seven estimated linkage groups and comprising approximately 68% of the total genome size of 2.03 gigabase pairs (Gbp). This assembly is expected to be a useful resource for genetic improvement of this emerging cover crop species as well as to provide useful insights into plant genome evolution.

genomics↗

bioRxiv2022

Chromosome-scale assembly of the highly heterozygous genome of red clover (Trifolium pratense L.), an allogamous forage crop species

Red clover (Trifolium pratense L.) is used as a forage crop due to a variety of favorable traits relative to other crops. Improved varieties have been developed through conventional breeding approaches, but progress could be accelerated and gene discovery facilitated using modern genomic methods. Existing short-read based genome assemblies of the ~420 Megabase (Mb) genome are fragmented into >135,000 contigs with numerous errors in order and orientation within scaffolds, likely due to the biology of the plant which displays gametophytic self-incompatibility resulting in inherent high heterozygosity. A high-quality long-read based assembly of red clover is presented that reduces the number of contigs by more than 500-fold, improves the per-base quality, and increases the contig N50 statistic by three orders of magnitude. The 413.5 Mb assembly is nearly 20% longer than the 350 Mb short read assembly, closer to the predicted genome size. Quality measures are presented and full-length isoform sequence of RNA transcripts reported for use in assessing accuracy and for future annotation of the genome. The assembly accurately represents the seven main linkage groups present in the genome of an allogamous (outcrossing), highly heterozygous plant species.

genomics↗