The Role Of No And Function Alanalysis Of Overexpression SlGSNOR Transgenic Plants Under Nitrate Stress

The soil secondary salinization is one of the global problems which seriously restricts the sustainable development of greenhouse vegetables.The results show that the ions in the secondary salinization soil is mainly NO3-,Ca2+ and K+.Nitric oxide(NO)is a signaling molecule which plays important roles in plants.NO combines with reduced glutathione(GSH)to create S-nitrosoglutathione(GSNO),which is a storage form of NO in vivo.S-nitrosoglutathione reductase(GSNOR)cancatalyze GSNO and release the oxidized glutathione(GSSG)and NH3.In this paper,we studied the effects of exogenous NO on the roots of tomato seedlings and the salt resistance of SlGSNOR overexpressing transgenic tomato and tobacco plants:1.Comparedwith the control,the MDA,H2O2 and ROS contents increased significantly,the activities of antioxidant enzymes(SOD,POD,CAT,APX and GR)and the contents of antioxidants(AsA and GSH)decreased significantly under nitrate stress.The MDA,H2O2 and ROS contents decreased significantly when adding(0.05,0.1,0.3,0.5,1 mM)SNP and(0.05,0.1,0.3,0.5 mM)GSNO,especially 0.1 mM SNP and 0.3 mM GSNO.The activities of SOD,POD,CAT,APX and GR and the contents of AsA and GSH increased significantly when adding SNP and GSNO,especially 0.1 mM SNP and 0.3 mM GSNO.Under nitrate stress,the content of NO increased significantly.The NO content increased with the increasing concentration of SNP and GSNO in the nitrate solution.Compared with the normal treatment,thc content of SNO increased significantly under nitrate stress.The content of SNO decreased significantly when adding SNP and GSNO to the nitrate solution,cspecailly 0.1 mM SNP and 0.3 mM GSNO.Under nitriate stress,adding 0.1 mM cPTIO to the nitrate soltion with 0.1 mM SNP reversed the function of SNP.2.The expression characteristics of SIGSNOR were analysed by qRT-PCR.The results showed that the transcript levels of SIGSNOR decreased under nitrate stress.The SIGSNOR expression increased when adding SNP and GSNO to the nitrate solution,especially 0.1 mM SNP and 0.3 mM GSNO.Under NaCl stress,the SIGSNOR expression increased firstly and decresed then,the expression shows the highest at 12 h.3.The function of SIGSNOR of were analysed using the SIGSNOR overexpression transgenic tomato and tobacco plants under nitrate and NaCl stress.First,genomic PCR,qRT-PCR and western blot analysis showed that we obtained the SIGSNOR overexpression transgenic tomato and tobacco plants.Then,the transgenic tomato and tobacco plants were treated with 100 mM Nitrate and NaCl for 1 and 3 days,and the physiological indexes were measured.The results showed that there were no significant difference of under the contents of MDA,H2O2,SNO,the antioxidants of ASA and GSH and the activities of antioxidant enzymesof transgenic lines and the wild types(WT),but the activity of GSNOR significantly higher than the wild types.Under nitrate stress,the contents of MDA,H2O2 and SNO significiantly lower than the WT,and the contents of antioxidants and the activities of antioxidant enzymes and GSNOR significiantly higher than the WT.Besides,overexpressing of SlGSNOR significantly increased the germination rates of transgenic tobacco under nitrate stress.These results indicated that overexpression of SIGSNOR enhanced the salt tolerance of tomatoes and tobacco.