Molecular Characterization Of LMW-GS Genes From Agropyron Cristatum

The low-molecular-weight glutenin subunits (LMW-GS) play critical role in determining the processing quality of wheat flours. So far, a large number of LMW-GS genes have been isolated from common wheat but few homologous gene has been isolated from wheat wild relatives Agropyron cristatum. By using PCR based cloning strategies, the LMW-GS has been isolated and sequenced. The main results are as follows:1. A total of27LMW-GS genes were obtained from Agropyron cristatum. Among them,15genes are predicated as proteins by having complete open reading frames, and7and5pseudogenes are caused by frame shift and in-frame stop codons. These sequences varied from828to954bps in nucleotide length and274to309residues in amino acid lengths.2. These sequences shared the typical primary structure with the LMW-GS from common wheat. Based on N-terminal residues, these sequences were classified as LMW-m (N-terminal sequence:MESSRTP-)、LMW-i (IGQQQPL-), and three new types with N-terminal sequence FRQQQPL-、TLQPQQT-and QQQLPQQ-.3. Sequence alignment indicated that genes of Agropyron cristatum with N-terminal sequence QQQLPQQ-were cluster together with none of the homologous genes from A、B and D genome of wheat. While, the rest of the genes were cluster together with the homologous genes from B genome of wheat.4. Genes with8or9cysteine residues were predicted to have some impact on the quality.