Wild barley (Hordeum spontaneum) represents a significant genetic resource for crop improvement in barley (Hordeum vulgare) and for the study of the evolution and domestication of plant populations. The Isa gene from barley has a putative role in plant defense. We identified 16 Single Nucleotide Polymorphisms (SNPs) in the coding region of the Isa locus of 189 wild barley accessions from 8 sites that were characterized for 16 ecogeographical variables. The pattern of SNPs suggested a large number of recombination events within this gene and 7 amino acid substitutions were present in the coding region. Highly significant correlations were found between diversity at the Isa locus and key water variables - evaporation, rainfall, humidity and latitude. The association is evident at both a local and regional level. These results are consistent with the possibility that inhibition of the plant’s own α-amylase by BASI (isa encoded protein) may be a novel plant defense function. Study of the promoter and coding region of this gene indicate evolution of function at both levels.
Cronin, JK, Bundock, PC, Furtado, A, Henry, RJ & Nevo, E 2007, ‘Diversity in a plant defense locus in wild barley populations is strongly correlated with water availability’, paper presented to Plant and Animal Genomes Conference XV, Population and Conservation Genomics workshop, San Diego, USA, 13-17 January.