Leaf Proteome Profiling and Their Interactions To Determine Disease Tolerance in Grape

Mechanism of solar radiation transformed in to the grape berry as a sink through grape leaves is the most important factors affecting the yield. Florida Hybrid bunch (FH) grape is widely cultivated in US southeast region and is popularly known for wine and table grape. However, most commercial cultivars are highly susceptible to anthracnose and to various foliar diseases. Our goal was to determine molecular mechanisms involved in grape leaf during the berry development and anthracnose disease tolerance. The objective of this study was to determine genetic diversity of leaf protein expressions and their interactions among FH cultivars during their berry development and to understand their possible role in disease tolerance. Leaf proteins from FH cultivars were resolved on 2DE and characterized using Mass Spectrometry and the Vitis database. Comparative analysis of eight FH cultivars revealed 56 differentially expressed proteins belonging to pathogen response, photosynthesis, and metabolism. Anthracnose tolerant cultivars showed more abundant proteins compared to susceptible cultivars. These proteins include glutamine synthetase, pathogenesis-related, glyoxisomal malate dehydrogenase, chloroplast precursor, oxygen evolving enhancer protein. Enzyme assay and RT-PCR studies of selected genes suggest a positive correlation with protein expression among the cultivars. Protein interaction studies in leaf reveal that their expression of photosynthesis related proteins are more attenuated during berry development and ripening among tolerant grapes. Expression of antioxidant proteins (e.g. ascorbate peroxidase, superoxide dismutase and peroxidase) declined in leaf at the early berry ripening stage suggesting a positive relationship connecting the source and sink organs of the grapes.