Comparison Of Salt Tolerance Of Three Lycium Varieties And Identification Of Salt Tolerance Of LbHKT Gene

The world's saline land area accounts for about 1/3 of the land area.All types of saline-alkali land in the China are 1×10~6square kilometers,and the area of cultivated saline-alkali land has reached 76000 square kilometers.Due to various unreasonable land use,the area of saline-alkali land is constantly expanding.Lycium barbarum has become the first choice for desert and saline-alkali land management in the Northwest of China,due to its superior ecological benefits such as wind-proof and sand-fixing,soil improvement and ecological environment improvement.It has received close attention in recent years due to its edible,nutritional and medicinal value.In order to solve the problem of reasonable selection of Lycium barbarum germplasm in saline-alkali land,many scholars have studied the salt tolerance and plant mechanism of salt damage to plants,cloned many salt-related genes,and obtained transgenic plants with high salt tolerance,thus showing attractive prospects.In this study,based on the physiological response of three Lycium planting resources to salt stress,combined with the physiological phenotype of the plant under salt stress and the analysis of the obtained data,the salt resistance of the three Lycium germplasms was determined,and one of them was selected.Excellent germplasm resources of Lycium barbarum salt resistance.The HKT1 gene of Lycium barbarum cloned by the laboratory using the RACE method was tested on the tomato transgene of the same solanaceae,and the expression of the salt resistance gene in the solanaceae was verified.On this basis,the salt resistance gene of the Lycium barbarum was further analyzed and obtained.The theoretical basis also provides some support for the molecular mechanism of salt resistance of Lycium barbarum in the future.The results are as follows:(1)Through the analysis of the significant difference in the seed germination rate and germination number of the three species of Lycium under the treatments of 0 mmol/L and100 mmol/L Na Cl,the order of the salt resistance of seed germination from strong to weak is:Lycium ruthenicum is the strongest,Ningqi 1 and Ningqi 7 are the weakest,and there is no difference in the salt resistance ability of the two seeds.(2)Obtain the seedlings of three varieties of Lycium barbarum by tissue culture,and count the changes in the growth of the main roots and the number of lateral roots after being treated with 0 mmol/L?150 mmol/L and 200 mmol/L MS medium salt stress.Analyze the salt tolerance of the roots of three wolfberry varieties.It was found that Lycium ruthenicum had the strongest salt tolerance under the treatments of 150 mmol/L and 200 mmol/L,followed by Ningqi No.7 and Ningqi No.1 the weakest.(3)Perform NBT and DAB histochemical staining on the seedling leaves after salt treatment on the medium to observe the changes of reactive oxygen species.It was found that Lycium ruthenicum leaves the lightest coloration and the least accumulation of active oxygen,Ningqi No.7 followed by Ningqi No.1 the most,indicating that Lycium ruthenicum had the least oxidative stress and Ningqi No.1 the most.(4)Under the treatment of 200mmol/L Na Cl for 12 hours,the expression of Lb HKT1gene in Ningqi 7 leaves gradually decreased,while in Ningqi 1 and Lycium ruthenicum,both first increased and then decreased,and finally returned to the control Level.It shows that Lb HKT1 plays an important role in the short-term salt response of Ningqi 1 and Lycium ruthenicum.It also shows that the salt resistance mechanisms of different Lycium ruthenicum varieties are different and the expression level in Lycium ruthenicum is higher than the control group for most of the time.(5)To explore the cloned Lb HKT1 salt-tolerance gene,it was constructed on the plant binary overexpression vector p CAMBIA1304,and transformed into Agrobacterium GV3101.The overexpression vector was transformed into tomato through Agrobacterium-mediated method.T0 generation positive seedlings were screened through antibiotic screening and PCR identification,and the harvested T0 generation seeds were planted after accelerating germination,DNA was extracted,and the target bands of the leaves were amplified by PCR to determine whether the inheritance was stable.