Project description:Salinity is a major constraint on agricultural productivity worldwide. Despite the serious impacts of salinity on rice yields, particularly in Asia, mechanisms of salt tolerance in wild rice species are yet to be explored. Here we extracted and quantified root microsomal proteins of Oryza australiensis accessions contrasting in salt tolerance. Whole root systems of two-week-old seedlings were treated with 80 mM NaCl for 30 days or left untreated. Proteins were quantified by tandem mass tags (TMT) and triple-stage MS. We found >200 differentially expressed proteins (DEPs) between the salt-treated and control in the two accessions (p-value <0.05). Gene Ontology (GO) analysis showed that ‘metabolic process’, ‘transport’ and ‘transmembrane transporter’ activities were highly responsive categories following salt treatment of the O. australiensis seedlings. In particular, ATPases and SNARE proteins were up-regulated in the salt-tolerant accession and appeared to have a major role in response to salinity. ATPases are the central link between energy generation and transport, while SNARE proteins facilitate vesicle fusion and interact with voltage-gated potassium channels to regulate K+ influx. We successfully validated the putative function of two strongly upregulated proteins, a monosaccharide transporter and a VAMP-like protein, by measuring the growth under salinity of yeast mutants in which homologous genes were deleted. Our results demonstrate the potential use of wild species as a source of new mechanisms of salt tolerance for the breeding of elite cultivars of rice.
