Genetic Transformation of Lycium Barbarum TGA2 Gene in Arabidopsis Enhances Its Salt Tolerance
In this study,TGA2 was cloned by RACE method from Lycium barbarum and performed sequence analysis.The TGA2 promoter sequence was cloned by PCR,and the overexpression vector pCAMBIA 2300EGFP-TGA2 was constructed to transform Arabidopsis thaliana.TGA2 subcellular localization was performed,and the response of the transformed A.thaliana to NaCl stress was also analyzed.The results show that TGA2 has a total length of 2 281 bp and encoded 493 amino acids.The upstream promoter sequence of TGA2 is 2 479 bp,with multiple cis-acting elements involved in plant hormone and light signal response.Phylogenetic analysis shows that the amino acid sequence of TGA2 from L.barbarum is highly similar to that of TGA2 from Anisodus acutangulus.TGA2 is located in the nucleus and exhibits transcriptional activation activity.Under different concentrations of NaCl stress,the expression level of TGA2 in transgenic A.thaliana was higher than that in wild-type,and the tolerance of transgenic TGA2 A.thaliana to NaCl stress was significantly enhanced.Physiological level test showed that under the same concentration of NaCl stress,the content of ABA,SA,and SST in TGA2 transgenic A.thaliana was significantly increased compared to wild-type.Under the stress of 0-100 mmol·L-1 NaCl,the GST activity of TGA2 transgenic A.thaliana was higher than that of wild-type.Under 300 mmol·L-1 NaCl stress,TGA2 transgenic A.thaliana showed higher SOD,POD,and CAT activities and lower MDA content compared to wild-type.These indicate that TGA2 gene can effectively alleviate the membrane lipid peroxidation caused by salt stress in A.thaliana,and enhance its resistance to salt stress.
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