Salt Tolerance Identification Of Soybean And Transformation Of SgP5CS Gene

Soybean is a moderately salt-tolerant crop,which has self-regulation ability to salt stress,but cannot grow normally under high concentration of salt damage.High concentration of salt stress will result in soybean yield reduction.Therefore,traditional breeding and advanced biotechnology are used to screen and cultivate salt-tolerant soybean varieties.Salt-tolerant soybean can maintain growth and productivity in saline soil,which can enhance the current soybean production in China,solve the problem of insufficient supply and demand,and also improve the soil,with good social and economic effects.In this study,98 and 57 cultivated soybean varieties were identified for salt tolerance in germination and seedling stages.The salt tolerance of 20 genetically modified soybean materials was evaluated by membership function method,and the salt tolerance mechanism was further analyzed to provide basis for breeding salt tolerant soybean varieties in the future.The main results are as follows:1.Salt tolerance evaluation of 98 soybean materials at germination stage:Salt tolerance was screened by measuring seed germination rate,germination potential,bud length and number of lateral roots.The results showed that soybean seeds different germination rates by 120 mM NaCl treatment,among which Chadou,Zhexian No.9,26008-1,SP349 and Zhe764-38 showed high salt tolerance;58cultivars such as Aijiaobaimao and Zhexian 21 showed moderate tolerance;35soybean varieties,such as SP327 and 03276,were not tolerant to salt,which showed the great difference of salt tolerance among different soybean varieties at germinationstage.2.Salt tolerance evaluation of 57 soybean materials at seedling stage:Salt tolerance was screened by measuring salt damage index.The results showed that soybean seedlings by 120 mM NaCl and 150 mM NaCl salt stress,among which 8 varieties showed high salt tolerance,9 varieties showed salt tolerance,12 varieties showed moderate salt tolerance,10 varieties showed sensitivity,and 18 varieties showed high sensitivity.Highly sensitive varieties were more,followed by moderately salt-tolerant varieties,and highly salt-tolerant varieties were the least.502,Zaolu 3D099,Liao31-7 and U3112 were less affected by salt stress and had strong salt tolerance,while H069?SMV006 and VP10 were nearly dead and could not grow under salt stress.3.Identification of salt tolerance of 20 transgenic soybeans during the whole growth period:In this experiment,20 transgenic soybeans were identified for salt tolerance in the whole growth period of the field by membership function method.The results showed that four salt tolerant varieties J001,J357,J358,J378 and 5 moderate salt tolerant varieties J002,J067,J070,J379 and J354 were identified under 200 mM NaCl stress.4.Genetic transformation of SgP5 CS gene:Overexpression of P5 CS gene increases the content of proline in plants,enhances the ability of emergency defense and improves the tolerance of plants.In this study,P5 CS gene was cloned from Suaeda salsa,named SgP5 CS,and plant expression vector SgP5CS-pCAMBIA1301-gfp was constructed.The SgP5 CS gene was transferred into Arabidopsis by floral dip method mediated by Agrobacterium.The preliminary results showed that SgP5 CS had been integrated into Arabidopsis genome by PCR detection of the target gene.