Sequencing of 15622 gene-bearing BACs clarifies the gene-dense regions of the barley genome

Abstract

Barley (Hordeum vulgare L.) possesses a large and highly repetitive genome of 5.1Gb that has hindered the development of a complete sequence. In 2012, the International Barley Sequencing Consortium released a resource integrating whole-genome shotgun sequences with a physical and genetic framework. However, because only 6278 bacterial artificial chromosome (BACs) in the physical map were sequenced, fine structure was limited. To gain access to the gene-containing portion of the barley genome at high resolution, we identified and sequenced 15622 BACs representing the minimal tiling path of 72052 physical-mapped gene-bearing BACs. This generated 1.7Gb of genomic sequence containing an estimated 2/3 of all Morex barley genes. Exploration of these sequenced BACs revealed that although distal ends of chromosomes contain most of the gene-enriched BACs and are characterized by high recombination rates, there are also gene-dense regions with suppressed recombination. We made use of published map-anchored sequence data from Aegilops tauschii to develop a synteny viewer between barley and the ancestor of the wheat D-genome. Except for some notable inversions, there is a high level of collinearity between the two species. The software HarvEST:Barley provides facile access to BAC sequences and their annotations, along with the barley-Ae.tauschii synteny viewer. These BAC sequences constitute a resource to improve the efficiency of marker development, map-based cloning, and comparative genomics in barley and related crops. Additional knowledge about regions of the barley genome that are gene-dense but low recombination is particularly relevant.

Keywords

Barley; Hordeum vulgare L; BAC sequencing; gene distribution; recombination frequency; synteny; centromere BACs; HarvEST:Barley; Aegilops tauschii

Published in

Plant Journal
2015, volume: 84, number: 1, pages: 216-227
Publisher: Wiley-Blackwell

SLU Authors

• Falk, Anders

  • Department of Plant Biology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Plant Biotechnology

Publication identifier

• DOI: https://doi.org/10.1111/tpj.12959

Permanent link to this page (URI)

https://res.slu.se/id/publ/73029