The wheat low-molecular-weight glutenin genes: characterization of six new genes and progress in understanding gene family structure

Although the low-molecular-weight (LMW) glutenin subunits are important for aspects of wheat quality and dough processing, a detailed description of the DNA structure and encoded polypeptides of this multigene family is still lacking. We report progress in obtaining a more thorough description of the LMW-glutenin gene family from a single wheat cultivar ('Cheyenne'). Six new genomic sequences are reported and compared with other LMW-glutenin DNA sequences. Subfamilies of sequences are identified, and an analysis of the repetitive domain of these polypeptides suggests a simple codon pattern with implications for modes of evolution of these repeat motifs. Southern analysis is used to estimate 30-40 members of this gene family in cv 'Cheyenne', and chromosome assignments are made for most restriction fragments, including the six sequenced genes. The known DNA sequences cluster into two groups, and most of the new sequences are tentatively identified as C-type LMW-glutenins. Representatives of the B-genome genes are still lacking.