Molecular Detection And Drought Resistance Analysis Of Transgenic Soybean MsSGTL1-TR1 In T₄ And T₅generations

China is a large agricultural country,but with the factors of global warming and population increase,domestic soybeans are in short supply.Drought is one of the reasons that limit the yield of soybean.It inhibits the normal growth and development of soybean and brings huge losses to the soybean industry.Breeding new drought resistant soybean varieties by genetic engineering technology,By enhancing the drought resistance of soybean and increasing the yield of soybean,we can alleviate the domestic soybean demand.In the early stage of the laboratory,MsSGTL1 gene and marker gene bar were introduced into the receptor material DN50 to obtain drought resistant transgenic soybean.In this study,molecular detection,indoor and field drought resistance identification and agronomic character analysis were carried out for T₄and T₅generations of mssgtl1 transgenic soybean lines.1.Molecular detection of T₄and T₅transgenic soybean lines MsSGTL1-TR1Southern detection of T₄and T₅transgenic soybean lines MsSGTL1-TR1showed that the exogenous T-DNA was inserted into the receptor DN50 in the form of single copy.PCR results showed that soybean TR1 transgenic with MsSGTL1 gene was a homozygous line that could be inherited stably.QRT PCR showed that MsSGTL1 gene and bar gene were expressed in different tissues of transgenic soybean line MsSGTL1-TR1,and the expression level of MsSGTL1 gene was higher in roots and leaves.The results of bar test strip,Western hybridization and ELISA showed that bar protein could be stably expressed in T₄and T₅transgenic soybean lines MsSGTL1-TR1,with the highest expression in leaves and the lowest expression in pods.2.Drought resistance analysis of transgenic soybean line MsSGTL1-TR1 at bud stage and Seedling StageAfter treated with-0.5 MPa PEG-6000 hypertonic solution for 8 days,the relative germination rates of T₄and T₅transgenic soybean lines were 96.43%and96.55%respectively,and the relative germination rates of T₄and T₅dongnong50were 76.67%and 70.00%respectively.The results showed that the seeds of transgenic soybean lines had higher drought resistance than those of recipient DN50.It was found that the wilting degree of wild-type soybean DN50 was significantly higher than that of transgenic soybean line MsSGTL1-TR1 under drought stress.The results showed that the transgenic soybean line MsSGTL1-TR1 at seedling stage had higher drought resistance than the DN50.3.Analysis of physiological indexes of T₄and T₅transgenic soybean lines MsSGTL1-TR1 under drought stressThe physiological indexes of T₄and T₅transgenic soybean lines MsSGTL1-TR1under drought stress were detected.We found that under drought treatment,the proline,soluble protein,soluble sugar content and antioxidant enzyme activity of transgenic soybean line MsSGTL1-TR1 were significantly higher than those of wild-type DN50;DAB and NBT staining experiments under drought stress showed that the coloring of transgenic soybean line MsSGTL1-TR1 was significantly shallower than that of DN50,indicating that transgenic soybean lines accumulated less H₂O₂and O₂^-than DN50.4.Drought resistance analysis of T₄and T₅transgenic soybean line MsSGTL1-TR1 at maturityBefore drought stress,there was no significant difference in biomass and agronomic characters between T₄and T₅transgenic soybean line MsSGTL1-TR1 and wild-type DN50.After drought treatment of T₄and T₅generation transgenic soybean lines MsSGTL1-TR1 in the field,it was found that the plant height,fresh weight,dry weight and chlorophyll content at seedling stage and flowering stage were significantly higher than those of wild-type DN50,and the plant height,pod number per plant,grain number per plant and 100 grain weight of transgenic soybean lines at maturity were significantly higher than those of wild-type DN50,The results showed that the transgenic soybean line MsSGTL1-TR1 had higher drought resistance than the DN50.5.Analysis of nutritional components of T₄and T₅transgenic soybean lines MsSGTL1-TR1The nutritional components of transgenic soybean line MsSGTL1-TR1 and DN50 after drought treatment were analyzed.The results showed that there was no significant difference in grain protein and oil content between transgenic soybean line MsSGTL1-TR1 and DN50.