Expression of HbTRXh5 Gene of Hevea brasiliensis in Yeast and Analysis on Its Resistance to Stress
[Objective]Cloning and analysis of expression characteristics of the thioredoxin gene HbTRXh5 from rubber tree(Hevea bsinensis),exploring its function in abiotic stress,which aims to provide genetic resources for genetic improvement of stress tolerance in rubber tree.[Method]RT-PCR method was used to clone HbTRXh5 gene from rubber tree,and bioinformatics methods were employed to analyze its sequence characteristics and phylogenetic relationship.Quantitative real-time PCR was applied to analyze the expressions of HbTRXh5 in various tissues of rubber trees and under abiotic stress.The yeast expression vector of HbTRXh5 was constructed and transformed into yeast,and then the survival differences between transgenic yeast and control yeast after cold,salt,and oxidative stress treatments were compared.[Result]The coding region of HbTRXh5 gene was 354 bp in length and encoded 117 amino acids.HbTRXh5 contained a conserved thioredoxin domain and a CGPC active site,belonging to the subgroup I of h-type thioredoxin.HbTRXh5 was expressed in various tissues of rubber tree,with the highest expression in latex.Low temperature,salt,and oxidative stress-induced by H2O2 and methyl violet up-regulated the expression of HbTRXh5.HbTRXh5 gene was successfully transformed into the yeast strain INVSc1 and induced to have expression.Compared with the control yeast transformed with the pYES2 empty vector,the HbTRXh5 gene transgenic yeast had a higher survival rate after H2O2 treatment,but showed a lower survival rate after cold and salt stress treatments.[Conclusion]The expression of HbTRXh5 is regulated by low temperature,salt,and oxidative stress in rubber tree.The overexpression of HbTRXh5 in yeast enhances the tolerance to oxidative stress,but reduces the tolerance to low temperature and salt stresses.
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