Effects Of NO And Protein S-nitrosylation On Tomato Seedlings Growth And Development Under Salt Stress

As an important signaling molecule,nitric oxide(NO)is involved in the growth and development and stress resistance of many plants.Meanwhile,previous studies have shown that NO can regulate the expression of some resistance-related genes in response to plant stress.In addition,NO can also regulate target protein activity,subcellular localization and function by protein post-translational modification of S-nitrosylation.This study explored the relationship between NO and S-nitrosylation in regulating the growth and development of tomato seedlings through regulating the expression of the related genes.The results were as follows:(1)Compared with the control,150 mM NaCl significantly inhibited the plant height,leaf area and total root length of tomato seedlings,and plant height was decreased by 28%.The application of 10 ?M NO donor GSNO can obviously alleviate the inhibition of salt stress on tomato seedling growth,while the application of NO scavenger cPTIO weakened the alleviation effect of NO under salt stress.(2)NO was significantly enhanced by 150 mM NaCl,which was twice that of the control.The donor of NO enhanced the salt stress-induced endogenous NO content,which increased 193% than that of the control,while cPITO weakened the salt stress-enhanced NO production.Meanwhile,both salt stress and GSNO enhanced the content of endogenous SNOs,GSNOR activity,GSNOR gene expression and the corresponding protein S-nitrosation level.(3)Biotin swith method was used to perform mass spectrometry analysis of S-nitrosylated proteins.The maximum number of S-nitrosylated proteins was identified in salt-stressed tomato seedlings.We identified 549,788,680 S-nitrosylated proteins in tomato seedlings in control,NaCl,NaCl+GSNO,respectively.These proteins are mostly located in three organs: chloroplast,cytoplasm and mitochondria.The S-nitrosylated proteins identified in this experiment covered a wide range of protein functions,including transport and metabolism of carbohydrates,post-translational modifications,protein renewal,molecular chaperones,translation,ribosome structure and biogenesis,amino acids transport and metabolism;KEGG annotation results indicate that these S-nitrosylated proteins were involved in many signaling transduction pathways,especially the MAPK signaling pathway,and stress response signal cascade.(4)Transcriptome sequencing was used to analyze the differential expression genes under NaCl treatment and GSNO + NaCl treatment,and these genes were annotated with GO and KEGG.Compared with salt stress,739 differential expression genes were identified by treatment of GSNO + NaCl,with 426 genes down-regulated and 313 genes up-regulated.KEGG annotations indicate that most of the differentially expressed genes of NaCl + GSNO vs NaCl were classified into photosynthesis,taurine metabolism,glyceride metabolism,mutual conversion of pentose and gluconate,plant MAPK signaling pathway,plant circadian rhythm and plants hormone signal transduction process,etc.