Cloning And Sequence Analysis Of Low Molecular Weight Glutenin Subunit Gene

Low-molecular-weight glutenin subunits (LMW-GS) is one of the wheat storage proteins. It has a significant impact on the processing quality of bread and pasta. But as a multi-copy gene, the sequence of the LMW-GS gene is of high similarity and thus is difficult to be identified effectively and thoroughly, which greatly hampers its application in molecular breeding. In this paper,37 sequences were cloned by using locus-specific primers and the PCR method. Based on the phylogenetic analysis and the genetic diversity analysis of these sequences, the relationship between them was discussed. It provides a theoretical reference for more efficient, faster and more precise analysis of the LMW-GS gene number, structure and features and the development of more systematic selection system assisted by molecular marker. The main results of this study are as follows.By taking the diploid, tetraploid and ordinary hexaploid wheat as test materials, the effectiveness of loci-specific primers for amplifying locus Glu-A3, locus Glu-B3 and locus Glu-D3 on LMW-GS gene was validated respectively.37 LMW-GS gene sequences were obtained through clone with the Genbank accession numbers being KF020658-KF020665, KJ406180-KJ406183 and KJ152523-KJ152547. Among these gene sequences,13 gene sequences had the Glu-A3 locus,12 had the Glu-B3 locus and 12 had the Glu-D3 locus.Among the 37 LMW-GS gene sequences, KJ152523, KJ152525-KJ152527, KJ152540, KJ152541 and KJ152544-KJ152547 were i-type genes and were located in the Glu-A3 locus, while the other 27 sequences were m-type DNA sequences. There were 7 cysteine residues in the amino acid sequences deduced from KJ152541 (Glu-A3), KJ406180 (Glu-B3), KJ406182 (Glu-B3), KJ406183 (Glu-B3), KJ152535 (Glu-D3) and KJ152539 (Glu-D3), while the number of cysteine residues corresponding to KJ152540 (Glu-A3) and KF020660 (Glu-B3) was nine and the others was 8.Comparative analysis of the allelic variation of loci Glu-A3, Glu-B3 and Glu-D3 demonstrates that the allelic variation in loci Glu-A3 and Glu-B3 is larger while in the locus Glu-D3 is relatively conservative.