Analysisofthebreadwheatgenomeusing whole-genome shotgun sequencing

Bread wheat (Triticum aestivum) is a globally important crop, accounting for 20 per cent of the calories consumed byhumans. Major efforts are underway worldwide to increase wheat production by extending genetic diversity andanalysing key traits, and genomic resources can accelerate progress. But so far the very large size and polyploidcomplexity of the bread wheat genome have been substantial barriers to genome analysis. Here we report thesequencing of its large, 17-gigabase-pair, hexaploid genome using 454pyrosequencing, and comparison of this withthe sequences of diploid ancestral and progenitor genomes. We identified between 94,000 and 96,000 genes, andassigned two-thirds to the three component genomes (A, B and D) of hexaploid wheat. High-resolution syntenymaps identified many small disruptions to conserved gene order. We show that the hexaploid genome is highlydynamic, with significant loss of gene family members on polyploidization and domestication, and an abundance ofgene fragments. Several classes of genes involved in energy harvesting, metabolism and growth are among expandedgenefamiliesthatcouldbeassociatedwithcropproductivity.Ouranalyses,coupledwiththeidentificationofextensivegenetic variation, provide a resource for accelerating gene discovery and improving this major crop.With a global output of 681 million tonnes in 2011