MutMap-Gap: whole-genome resequencing of mutant F2 progeny bulk combined with de novo assembly of gap regions identifies the rice blast resistance gene Pii

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Summary

  • Next-generation sequencing allows the identification of mutations responsible for mutant phenotypes by whole-genome resequencing and alignment to a reference genome. However, when the resequenced cultivar/line displays significant structural variation from the reference genome, mutations in the genome regions missing from the reference (gaps) cannot be identified by simple alignment.
  • Here we report on a method called ‘MutMap-Gap’, which involves delineating a candidate region harboring a mutation of interest using the recently reported MutMap method, followed by de novo assembly, alignment, and identification of the mutation within genome gaps.
  • We applied MutMap-Gap to isolate the blast resistant gene Pii from the rice cv Hitomebore using mutant lines that have lost Pii function.
  • MutMap-Gap should prove useful for cloning genes that exhibit significant structural variations such as disease resistance genes of the nucleotide-binding site-leucine rich repeat (NBS-LRR) class.

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