Contribution of α-gliadin alleles to the extensibility of flour dough in Japanese wheat cultivars

Alpha-gliadins are one of the major seed storage proteins in wheat and considered involved in wheat dough extensibility. We investigated the relationship between a-gliadin allele types and the extensibility of the resulting flour dough. In a preliminary survey, we identified 26 unique alpha-gliadin genes expressed in Triticum aestivum L. 'Chinese Spring', an experimental standard cultivar. These genes are encoded in three Gil-2 homoeoloci, and consist of seven Gli-A2, twelve Gli-B2, and seven Gli-D2 genes. Using specific primers for each gene, we then found that all three homoeoloci are associated with flour dough extensibility, as measured on an AlveoConsistograph. Importantly, the relationship between Gli-A2 genes and flour dough extensibility is robust, as surveyed in available cultivars from different seasons. These results suggest that alpha-gliadin genes in chromosome 6A contribute to dough extensibility and that genotyping such genes may facilitate breeding programs to improve flour dough quality.