Map based cloning of cer-zv mutant. Hordeum vulgare strain:cer-zv and Foma

cer-zv, a barley cuticle mutant defective in cutin formation, mapped to an interval of 0.02 cM on a pericentromeric region of barley chromosome 4H. Although this interval is genetically very small, it nevertheless represents a large proportion of the chromosome arm because it supports a very low level of recombination. Since a map-based cloning approach to isolate the gene was therefore considered unlikely to be feasible, a comparison was instead made between the transcriptomes of the mutant and the WT. In conjunction with extant genomic information, the list of candidate genes was reduced to 36, all mapping within the target, and all of which harbored a mis-sense mutation in the cer-zv mutant. On the basis of predicted functionality, only two of the 36 genes were considered likely to encode a product associated with cutin formation. When a panel of cer mutants was re-sequenced with respect to the two candidate genes, the mutations of one candidate gene were related to the mutant phenotype .