Abstract:

In order to investigate the molecular mechanisms of protein responses in Triadica sebifera to salt stress， two T. sebifera lines， including salt-sensitive P18（SS18） and salt-tolerant P21（ST21） were selected and treated with 0.4% NaCl solution. Isotope tags for relative and absolute quantitation（iTRAQ） were used to quantify leaf proteins abundance changes at different stress periods（0， 24， 72 h）. A total of 279 and 106 differentially expressed proteins（DEPs） were detected in SS18 and ST21， respectively. Four proteins， including catalase， extension factor 1-α， H⁺-ATPase c domain protein and thioredoxin， were significantly up-regulated in two clones under salt stress， suggesting that they may be important potential target proteins in the salt-tolerant response of T. sebifera’s. Pathway enrichment analysis showed that the DEPs of T. sebifera leaves under salt stress were primarily associated with photosynthesis， carbohydrate metabolism， amino acid metabolism， and fatty acid metabolism. The protein-protein interaction network showed that 5 core proteins（24 h） and 3 core proteins （72 h） involved in glucose decomposition and energy metabolism in SS18， while ST21 had 5 （24 h） and 4 （72 h） core proteins involved in carbon metabolism， photosynthesis， carbon fixation， photosynthesis and related to chlorophyll a-b binding. ST21 leaves improved metabolic pathways of sugars， amino acids and fatty acids， and accumulated a large number of small molecular soluble substances such as soluble sugars， amino acids and organic acids under salt stress， which might be an important aspect of salt stress response.

Key words: Triadica sebifera, leaves, salt-stress, iTRAQ