Project description:Drought often compromises yield in non-irrigated crops such as rainfed rice, imperiling the communities that depend upon it as a primary food source. In this study, two cultivated species (Oryza sativa cv. Nipponbare and Oryza glaberrima cv. CG14) and an endemic, perennial Australian wild species (Oryza australiensis) were grown in soil at 40% field capacity for 7-d (drought). The hypothesis was that the natural tolerance of O. australiensis to erratic water supply would be reflected in a unique proteomic profile. Leaves from droughted plants and well-watered controls were harvested for label-free quantitative shotgun proteomics. Physiological and gene ontology analysis confirmed that O. australiensis is responded uniquely to drought, with superior leaf water status and enhanced levels of photosynthetic proteins. Moreover, distinctive patterns of expression of proteins in drought were observed across the entire O. australiensis proteome. An intermediate impact of drought on photosynthetic and stress-response proteins is reported in O. glaberrima relative to O. sativa but the drought response was most striking in O. australiensis. For example, photosynthetic proteins decreased when O. sativa after drought, while a narrower range of stress-responsive proteins was up-regulated. Distinctive proteomic profiles and the expression levels of individual proteins with specific functions in response to drought in O. australiensis indicate the importance of this species as a source of stress tolerance genes.
