Comparative proteomic analysis of different barley cultivars during seed germination

Abstract

Malting quality is an important determinant of the barley grain value used in brewing. Malting process is an accurately controlled barley germination followed by kilning and is modified according to the characteristics of the barley variety. However, the genetic mechanism of malting difference among varieties is still not clear. The present study aims to analyze the mechanism of malting performance variance about the different cultivars, especially the Chinese barley Gan-7. We identified brewing performance variance of Gan-7, Copeland, Spartacus and determined the variation in proteomic profiles among these cultivars. 114 proteins with significant differences between cultivars were identified and the roles of differential expression proteins in malt quality discrimination were elucidated according to their putative functions. The differentially expressed proteins mainly related to genetic information processing and carbohydrate metabolism pathways. Among them, we find that the poor α-amylase activity of Gan-7 is related to the low abundance of α-amylase. The performance of Gan-7 may be partly attributed to the differentially expressed proteins involved in starch hydrolysis, PRs, hordoindoline, hordein, trypsin inhibitor processes. In the present study, only barley variety used for malting was considered, and this can explain the cultivar effect of malting. These results may provide clues for optimizing the malting process for Chinese domestic barley cultivars, especially Gan-7.