The Regulatory Mechanism Of Protein Succinylation In Response To Salt Stress Of Lycium Barbarum

Lycium barbarum is a famous medicinal salt-tolerant woody plant with high medicinal,nutritional and ecological value.This study was investigated the protein succinylation modification in L.barbarum under different NaCl stress by Label free analysis.Bioinformatics analysis was carried out on the identified succinylation modified proteins,and the changes of key enzyme activities and substance contents of important physiological metabolic pathways involved in protein succinylation modification were measured.Meanwhile,the lipid component of lipid metabolism pathway were analyzed by targeted lipid metabolomics to analyze how L.barbarum responds to NaCl stress through protein succinylation modification and lipid changes.This study mainly obtained the following results:1.A total of 298 succinylated modified proteins,2009 succinylated modified peptides and 657 succinylated modified sites were identified in leaves of L.barbarum under different NaCl stress by Label free analysis.Among them,156 quantified succinylation modified proteins,642 quantified succinylation modified peptides and 351 quantified succinylation modified sites were identified.The identified succinylated modified proteins are mainly involved in biological processes such as photosynthesis and photorespiration,sugar metabolism,amino acid metabolism,lipid metabolism and protein synthesis and processing.2.Our research found that PSBO,PSBQ2,PsaEb,PsaD,PsaB,PETH the proteins of PSI,PSII and photosynthetic electron transport chain were significantly succinacylated.The succinylation levels of photosynthetic carbon fixation related proteins RbcL,RCA,CA,TKT,SBP,FBA3 and photorespiration related proteins CAT1.SHMT,GDCST and GDCSP were significantly increased under 100 or 200 mmol/L NaCl stress.Moreover,starch,sucrose and glucose,fixed products of photosynthetic carbon,were accumulated significantly.These results indicated that photosynthetic carbon fixation and photosynthetic respiration related enzyme activities of L.barbarum could be regulated by protein succinylation modification in response to NaCl stress.In addition,the proteins involved in the tricarboxylic acid cycle,amino acid metabolism and protein synthesis were also significantly succinylated.These results indicated that protein succinylation modification regulating multiple metabolic pathways responded to NaCl stress in L.barbarum.3.Correlation analysis of protein succinylation and acetylation revealed that 86 proteins were modificated by succinylation and acetylation.Among them,85 succinylation modification sites were simultaneously modificated by acetylation,which mainly participated in multiple biological processes such as carbon metabolism,carbon fixation in photosynthetic organisms,amino acid metabolism and fatty acid metabolism.These results indicated that the synergistic effect of these two modifications was involved in the response of L.barbarum to NaCl stress.4.The results of targeted lipids combined with protein succinylation showed that succinylated modified proteins of L.barbarum may affect the β-oxidation pathway in mitochondria and peroxisome under NaCl stress,which inhibited the degradation of fatty acid chain,increased the length of fatty acid chain and the fluidity of membrane lipid by increasing the degree of unsaturated fatty acid of L.barbarum in response to NaCl stress.Therefore,protein succinylation modification were mainly involved in regulated photosynthesis,photorespiration,glucose metabolism,amino acid metabolism,lipid metabolism,protein synthesis and processing of L.barbarum in response to NaCl stress.The results were further enriched the molecular and physiological mechanism of L.barbarum in response to NaCl stress at protein succinylation modification and lipid metabolism level.