comparative proteomic analysis of two barley cultivars (hordeum vulgare l.) with contrasting grain protein content

Grain protein contents of barley seeds are significantly different between feed and malting barley cultivars. However, there is still no insight into the proteomic analysis of seed proteins between feed and malting barley cultivars. Also, the genetic control of barley grain protein content is still unclear. Grain protein contents were measured between mature grains of Yangsimai 3 and Naso Nijo by using FOSS Kjeltec TM 2300. A proteome profiling of differentially expressed protein was established by using a combination of 2-DE, MALDI TOF MS and MS/MS. In total, 502 reproducible protein spots in barley seed proteome were detected with a pH range of 4-7 and 6-11, among these 41 protein spots (8.17%) were detected differentially expressed between Yangsimai 3 and Naso Nijo. Thirty-four protein spots corresponding to 23 different proteins were identified, which were grouped into eight categories, including stress, protein degradation and posttranslational modification, development, cell, signalling, glycolysis, starch metabolism and other functions. Among the identified proteins, enolase (spot 274) and small subunit of ADP-glucose pyrophosphorylase (spot 271) are exclusively expressed in barley Yangsimai 3, which may be involved in regulating seed protein expression. In addition, malting quality is characterized by an accumulation of serpin protein, Alpha-amylase/trypsin inhibitor CMb and Alpha-amylase inhibitor BDAI-1. Most noticeably, globulin, an important storage protein in barley seed, undergoes post-translational processing in both cultivars, and also displays different expression patterns.