Proteomic analysis of developing wheat grains infected by powdery mildew (Blumeria graminis f.sp tritici)

Blumeria graminis f.sp. tritici (Bgt) infection greatly interferes with the normal source-sink relationships and always causes tremendous loss of yield and quality in wheat. To better understand the impact of this pathogen on grain development, proteome characterization during grain development in susceptible wheat cultivar Xinong 979 infected by powdery mildew was investigated by 2-DE and tandem MALDI-TOF/TOF-MS. Identification of 111 differentially expressed protein spots representing 85 unique proteins and six expression patterns showed a chronological description of wheat grain formation. Comparative proteome profiles indicated that 43 protein spots displayed significant abundance change, which is mainly involved in stress/defense responses, primary metabolism, and storage protein. The down-regulation of defense response-related proteins including alphapurothionin, lactoylglutathione lyase, and alpha-amylase inhibitor CM16 in infected grains compared to control during seed filling might be related to the susceptibility of wheat to Bgt, while the enhanced expression of beta-amylase and glyceraldehyde-3-phosphate dehydrogenase and the down-regulation of ADP glucose pyrophosphorylase in infected grains probably resulted in the negative effects on yield formation. Our data reveal the complex grain metabolism mechanisms and defense responses during compatible interactions of wheat and Bgt, and provide valuable information for further understanding of the underlying molecular processes which can possibly yield novel strategies for breeding resistant cultivars and protection strategies in the field.