Identification A1a B1b -subunit deficiency of glycinin in soybean (Glycine max L. Merrill) seed by proteomics approach.

A mutant line was successfully selected from 220 soybean cultivars by using SDS-PAGE,which characterized by lack of a certain subunit of glycinin group I,seed protein proteome of the mutant line 'Guiyang zijindou' and cultivar 'Nannongdahuangdou' were compared using PDQuest software(Bio-Rad)after two-dimensional gel electrophoresis(2-DE),with the cultivar 'Nannongdahuangdou' as control.The results showed that three protein spots with pI 5.15,Mr 37.85 kDa;pI 5.24,Mr 37.2 kDa;pI 5.40,Mr 37.05 kDa respectively were present in seed protein of the cultivar 'Nannongdahuangdou',however,no protein spots were presented in the location of glycinin group I acid subunits of the mutant line.These three protein spots were identified by MALDI-TOF-MS,and peptide mass fingerprinting data were queried in NCBInr database by Mascot.All these proteins were identified as crystal structure of soybean proglycinin A1aB1b homotrimer.The results indicate that the mutant line lacking A1aB1b-subunits.