Analysis Of Salt And Drought Tolerance Of Wheat Overexpressing ZmTINY2 And AtNACL1 Genes

Wheat is one of the main food crops in China,and widely cultivated in the world.Abiotics stresses such as drought and salt seriously affected the development of wheat production.Digging out and using stress resistance genes,and cultivating breakthrough varieties are effective method to increase wheat yield.In previous study,the ZmTINY2 gene from maize was transformed into wheat F25-2,and the AtNACL1 gene from Arabidopsis thaliana was transformed into wheat Fielder through Agrobacterium-mediated transformation.To evaluate the resistance characteristic to salt and drought of the transgenic materials,a series experimental were conduct.The results are as follows:(1)Identification of transgenic materialsThe DNA was extracted from the seedlings of transgenic wheat,and used to amplified the transformed exogenous genes.A total of 91 strains of transgenic ZmTINY2 gene wheat were identified,of which 73 were positive.Three hundred and fifty-five strains of transgenic AtNACL1 gene wheat were identified,232 of which were positive.(2)Evaluated of salt and drought resistance of transgenic ZmTINY2 gene wheatTransgenic ZmTINY2 wheat and control F25-2 wheat seeds were germinated 7 days under different concentrations of NaCl and PEG-6000 solution.Through comparing the germination potential,germination rate,root length,seedling length,fresh weight,etc.,it was found that the germination rate of transgenic ZmTINY2 wheat was increased by 15%,the average seedling length and root length increased by about 1 cm under the process of 15% PEG solution,and the average seedling length increased by 2 cm,the average root length increased by nearly 1cm under the treament of 150 mM NaCl solution,and the germination rate increased by 20% under the treament of 200 mM NaCl solution.The above results show that the transgenic material is more drought-resistant and salt tolerant than the control on the germination.Transgenic ZmTINY2 wheat and F25-2's seedlings were treated with 200 mM NaCl and 15% PEG aqueous solution,respectively.The chlorophyll,proline,malondialdehyde content and antioxidant enzyme activity of the wheats before and after the treatment were measured.It showed that the physiological indexes of drought resistance and salt tolerance are better in the transgenic wheat.(3)Evaluated of salt and drought resistance of transgenic AtNACL1 gene wheatThe same method was used to treat transgenic AtNACL1 wheat and the control wheat Fielder.Compared with the negative control,the germination rate of transgenic AtNACL1 wheat was increased by 13%,the average seedling length and root length increased by about 1 cm after treated with 250 mM NaCl solution for 7 days,the germination rate of transgenic AtNACL1 wheat was increased by 15% after treated with 250 mM NaCl solution for 7 days,and the transgenic materials had better salt-tolerance physiological indexes at seedling stage.(4)Gene expression analysisTransgenic ZmTINY2 wheat and negative control wheat F25-2 were treated with 15% PEG and 200 mM NaCl aqueous solution,respectively,Fluorescence quantitative RT-qPCR was used to analyze the expression of ZmTINY2 gene at different time points under simulated drought and salt damage treatment.The results showed that there was no ZmTINY2 gene expression in control wheat F25-2,but there was a large amount of ZmTINY2 gene expression in transferred wheat.