A high-continuity and annotated reference genome of allotetraploid Siberian wildrye (Elymus sibiricus L., Poaceae: Triticeae)

Elymus sibiricus L. (Siberian wildrye, Es), a species belonging to the wheat tribe, is extensively employed as forage and for the reclamation of degraded grasslands within the Qinghai-Tibet Plateau (QTP). This study provides a high-quality reference genome assembly for the allotetraploid Es, which is composed of 14 pseudomolecules with the total genome size of 6.57 Gb. Our finding suggest that large-scale bursts of retrotransposons are critical for the genome expansion of Es. We discovered a translocation event between the Es4H and Es6H chromosomes with a low frequency of combination. Phylogenetic analyses of 90 Es accessions and 25 diploid accessions representing proposed ancestors from various habitats revealed the existence of four distinct populations. We further provided support for the hypothesis that the QTP is the center of origin and genetic diversity for Es. Collectively, our study offers valuable insights into the evolution of Es, as well as providing genomic resources for genetic enhancement in the Elymus genus and wheat tribe.