Barley Whole Exome Capture: A New Tool For Genomic Research In Barley

Advanced resources for genome-assisted research in barley (Hordeum vulgare) such as a whole genome shotgun assembly and an integrated physical map have recently become available. Studies aiming to assess genetic diversity or to isolate single genes can then apply a resequencing approach consisting of next generation sequencing and subsequent in silico variant detection. Targeted sequencing of the protein-coding part of the genome (the exome) offers a means to reduce the heavy sequencing load that would be required for reliable variant identification by resequencing of the whole 5.1 Gb barley genome.

We employed the Roche Nimblegen in-solution hybridization-based sequence capture platform to selectively enrich DNA from a non-redundant 61 Mb sized target region for sequencing. Targets included in the design were predicted genes on the genome assembly of the cultivar Morex as well as publicly available full length cDNA and de novo assembled RNAseq contigs. Coverage analyses of the capture space based on sequencing data obtained in pilot experiments indicated that the design is able to provide highly specific, substantial, and reproducible enrichment of targeted exons.

The barley exome capture can pave the way towards a broader and deeper understanding of the natural variation residing in the protein coding part of the barley genome and will thus constitute a valuable resource for applications such as mapping-by-sequencing or diversity studies between different cultivars of barley as well as its wild relatives.