Molecular Cloning of Agropyron intermedium Low-Molecular-Weight Glutenin Subunit Genes from a Triticum aestivum-Ag. intermedium Addition Line TAI-13

摘要

The glutenin composition and low-molecular-weight glutenin subunit (LMW-GS) genes of Triticum aestivum L.-Agropyron intermedium (Host) Beav alien addition set I (TAI-11-TAI-16) were analyzed by SDS-PAGE and genomic PCR, respectively. The results indicated that the addition line TAI-13 carries both high-molecular-weight glutenin subunit (HMW-GS) and LMW-GS gene loci and that the extra Ag. intermedium chromosome pair in TAI-13 belongs to homoeologous group 1. Four LMW-GS genes located on the added Ag. intermedium chromosome in TAI-13 line have been isolated from immature endosperm of TAI-13 by RT-PCR approach. Sequence analysis showed that three of them (13003, 13006 and 13054) contained complete ORFs of genes, the other one, 13514 was a partial gene lacking of coding sequence of signal peptide. According to the N-terminal amino acid sequences deduced from nucleotides, the four LMW glutenin subunits could be classified into three types, i.e. Ai-M type (LAi1 encoded by 13514), Ai-Q type (LAi2 and LAi3 encoded by 13006 and 13045, respectively) and Ai-I type (LAi4 encoded by 13003). Ai-M and Ai-Q are novel LMW-GS types compared with the known LMW-GSs of wheat. The analysis of deduced amino acid sequence showed that the LAi1 had the specific primary structure, nine Cys residues and longer repetitive region. These characters of LAi1 may have positive effect on strength and viscoelasticity of wheat flour.