Comparison Of Differences In Salt Tolerance Function Between Soybean And Tamarix SOS1 Genes

Salt stress is one of the important reasons leading to the hindrance of plant growth and development.Plants can adapt to environmental changes by reducing the accumulation of Na+and producing osmotic adjustment substances to produce a series of stress responses.The ion transport system in plants plays an important role in adapting to salt stress.The Na+/H+ antiporter SOS1 on the plasma membrane alleviates the ionic toxicity of plants in salt stress by excreting Na+in vitro.Soybean is an important oil crop,and salt stress is one of the main reasons affecting its yield.Therefore,it is important to study the salt tolerance mechanism of soybean.The halopHyte plant T.ramosissima(Tamarix ramosissima)is a plant with strong salt tolerance and can be used as a research material for salt tolerance.In this paper,we mainly studied the salt tolerance function of T.ramosissima SOS1 and soybean SOS1 gene,and compared the salt tolerance function of GsSOSl and TrSOS1 by yeast and hairy roots expression system.The main findings are as follows:There are differences in the salt tolerance of different soybean materials.By analyzing the transient expression of SOS1 gene in roots,stems and leaves of cultivated soybeans Lee68 and N23674(Glycine max)and wild soybean BB52(Glycine soja)under salt treatment conditions,the expression of SOS1 gene in roots,stems and leaves of three materials was similar,and its expression was similar.The amount of roots increased first and then decreased with the increase of salt treatment time.The expression of roots was significantly higher than that of stems and leaves.The expression of SOS1 gene was highest in Lee68,N23674 and BB52 roots at 6h after salt treatment.Compared with 0h,the expression of SOS1 gene was the highest in salt-tolerant variety BB52,which was consistent with the salt tolerance of wild soybean BB52 strain compared with cultivated soybean Lee68 and N23674 varieties.In order to analyze the salt tolerance function of soybean SOS1 gene,the GsSOS1 gene of wild soybean BB52 with strong salt tolerance was selected as the research object.GsSOS1 gene was subjected to site-directed mutagenesis and expressed into yeast plasma membrane mutant ANT3.The results showed that GsSOS1,S33T,G144E,T150I,A245V,A275V,R376C,G775D,G782E,S1136A and S1138A.were able to exclude Na+of the yeast mutant ANT3 on the medium of 100mM NaCl,and the growth of R376C was better than that of GsSOS1.However,G135E,E518G and A924T could not restore the growth of mutants,indicating that these mutation sites act as key sites of GsSOS1 to affect their salt tolerance.In order to analyze and compare the salt tolerance function of GsSOSl and TrSOS1,GsSOS1 and TrSOS1 were expressed yeast mutant ANT3 by yeast complementation,and both of them were able to exclude Na+.The intracellular Na+content and Na+/K+ratio were significantly higher than those of TrSOS1,indicating that the salt tolerance of TrSOS1 was better than that of GsSOS1.At the same time,Agrobacterium rhizogenes K599 hairy root composite plants were established.The seedlings of GsSOS1 and TrSOS1 hairy roots could reduce the content of Na+in roots,stems and leaves,increase the content of K+,decrease the ratio of Na+/K+,and increase the activity of antioxidant enzymes CAT,SOD and POD.It indicates that SOS1 gene can improve the Na+,K+ homeostasis in plants under salt stress and enhance the antioxidant capacity,thus enhancing the ability to resist salt stress.In summary,the expression of SOS1 gene in roots,stems and leaves of wild soybean BB52 strain under salt stress was higher than that of cultivated soybeans Lee68 and N23674;Expressed GsSOSl and TrSOS1 were able to exclude Na+of yeast mutant ANT3,and yeast cells expressed TrSOS1 better than GsSOS1 hair root overexpression of GsSOS1 and TrSOS1 can improve the salt tolerance of soybean,and the salt tolerance effect of TrSOS1 soybean material is better than of GsSOS1.