Diversity of low-molecular-weight glutenin subunit genes in Asian common wheat (Triticum aestivum L.)

Abstract

We analyzed the diversity of the low-molecular-weight glutenin subunit (LMW-GS) genes of Asian common wheat cultivars. Locus-specific primers for LMW-GSs revealed the presence of four alleles at the Glu-A3 locus, four at the Glu-B3 locus and one at the Glu-D3 locus. Frequency of Glu-A3 alleles in the Japanese cultivars was very different from that in other Asian cultivars. The combined alleles at the three Glu-3 loci were classified into 15 genotypes. The frequency of each genotype from the Asian collection or breeding areas varied. One Glu-3 genotype, BAA (consisting of the Glu-A3 allele B, Glu-B3 allele A and Glu-D3 allele A), occurred frequently in many Asian cultivars. Glu-3 genotypes BBA, CAA and DBA predominated in southern and northern Asia and in Japan, respectively. In addition, the Japanese cultivars with the BBA or CAA genotypes showed a specific composition of high-molecular-weight glutenin subunits and gliadins. DNA sequencing indicated that the Glu-A3 allele B carried an additional cysteine residue and that the allele C showed unusual amino-acid deletions. These mutations were likely to affect dough strength, which is a major characteristic of wheat flour quality.