Regulation Of Exogenous GSNO On Tomato Seedling Growth Under NaCl Stress

Tomato is a widely cultivated vegetable crop in the world.It is widely planted in open fields and facilities.In recent years,the growth and development of tomato were inhibited,the photosynthetic capacity was decreased,and the yield and quality were seriously decreased due to the secondary salinization of soil,which has become one of the important abiotic stress factors limiting the production level of tomato.Therefore,it is of great significance to study the salt tolerance and its regulation mechanism of tomato.In this study,tomato cultivar"Zhongshu No.4"was used as experimental material.Tomato Seedlings under NaCl stress(100 mmol·L^-1)were treated with NG:0.5 mmol·L^-1 GSNO（S-nitrosoglutathione,NO donor）,NP:1 mmol·L^-1 c PTIO（NO scavenger）,NGP:0.5 mmol·L^-1 GSNO compound 1 mmol·L^-1c PTIO.The effects of exogenous GSNO on salt adaptability and growth and development of Tomato Seedlings under NaCl stress were studied.The results are as follows:1.Exogenous GSNO could significantly increase the contents of proline（pro）,K⁺,Ca²⁺and Mg²⁺,reduce the electrolyte permeability,Malondialdehyde（MDA）and Na⁺contents,while exogenous c PTIO could weaken the effects of GSNO on the above indexes in varying degrees under Salt Stress.The results showed that exogenous GSNO could improve the osmotic adjustment ability of tomato seedling cells,reduce the degree of membrane lipid peroxidation and membrane structure damage,and reduce the toxicity of Na⁺,so as to reduce the inhibition of salt stress on tomato seedling growth.2.The application of exogenous GSNO increased chlorophyll content,Fv/Fm（PSII maximum photochemical efficiency）,q P（photochemical quenching coefficient）,Y（II）（actual photochemical efficiency）and ETR（photosynthetic electron transfer rate）of Tomato Seedlings under salt stress,and decreased Y（NO）（non-regulated energy dissipation）and NPQ（non-photochemical quenching）of tomato seedlings at 6 and 9 days.The initial and total activities of Rubisco,RCA,SBPase,PGK,GAPDH on the3rd and 6th day of treatment,and GAPDH on the 3rd and 9th day of treatment were up-regulated.The activity of FBPase（fructose-1,6-diphosphate）was determined.Compared with NG treatment,NGP treatment decreased chlorophyll content,NPQ on the 9th day,total Rubisco activity,initial Rubisco activity and RCA activity on the 6th and 9th day,SBPase and PGK activity on the 3rd and 6th day.These results indicate that exogenous GSNO can regulate photosynthetic activity,photosynthetic electron transport rate and PSII carbon assimilation efficiency of Tomato under salt stress,and improve tomato photosynthetic capacity.3.The leaf of tomato seedlings was analyzed by RNA-Seq technique under CK,N,NG,NP and NGP.The difference expression genes of CK vs N,N vs NG,N vs NP和NP vs NGP were statistically analyzed by GO and KEGG.The results showed that 1198,83,599 and 683 DEGs were selected from the four groups.The specific salt tolerant genes induced by GSNO were analyzed by differential expression.Exogenous GSNO can alleviate the adverse effects of salt stress on photosynthesis,redox stability and energy metabolism of Tomato Seedlings by regulating the expression level of glutathione metabolism related genes,phosphorylation and hormone signal transduction pathway,photosynthesis,carbohydrate metabolism and phenylpropane biosynthesis.