Chromosome-scale genome assembly of bread wheat’s wild relativeTriticum timopheevii

Abstract

Wheat (Triticum aestivum) is one of the most important food crops with an urgent need for increase in its production to feed the growing world.Triticum timopheevii(2n = 4x = 28) is an allotetraploid wheat wild relative species containing the Atand G genomes that has been exploited in many pre-breeding programmes for wheat improvement. In this study, we report the generation of a chromosome-scale reference genome assembly ofT. timopheeviiaccession PI 94760 based on PacBio HiFi reads and chromosome conformation capture (Hi-C). The assembly comprised a total size of 9.35 Gb, featuring a contig N50 of 42.4 Mb, and 166,325 predicted gene models. DNA methylation analysis showed that the G genome had on average more methylated bases than the Atgenome. The G genome was also more closely related to the S genome ofAegilops speltoidesthan to the B genome of hexaploid or tetraploid wheat. In summary, theT. timopheeviigenome assembly provides a valuable resource for genome-informed discovery of agronomically important genes for food security.