Studying On Ca²⁺-Dependent Nuclease Involved In Response To Stress In Arabidopsis Thaliana

Nucleases is a kind of protein that has the effect of hydrolyzing the phosphodiester bond between nucleotides,in the first step of nucleic acid decomposition.They are widely found in living organisms and have a very important role in biological physiology.In this study,we used Ca²⁺-dependent nuclease gene of Arabidopsis as the research object,and analyzed its expression regulation and physiological function in Arabidopsis.The Ca²⁺-dependent nuclease gene family in Arabidopsis has two members: AtCa N1 [TAIR: At3g56170] and AtCaN2 [TAIR: At2g40410].We used real-time quantitative PCR to analyze the expression of AtCaN2 gene and At Ca N1 gene in wild-type Arabidopsis thaliana,and to study its expression characteristics when the plants were subjected to salt stress treatment.The expression patterns of AtCaN2 gene and AtCa N1 gene were preliminarily described by the results.It was found that both AtCa N2 and At Ca N1 genes were the most expressed in senescent pods,indicating that they may all be genes related to senescence,and they were all induced by salt stress and were involved in stress response.At the same time,we analyzed phenotypic and some physiological indicators of the wild type Arabidopsis,AtCa N2 gene overexpression,At CaN1 gene overexpression and their mutant Arabidopsis strains in the case of NaCl stress treatment.The results showed that the Arabidopsis thaliana,whether it was overexpressed by AtCa N2 gene or AtCa N1 gene overexpression,was weaker than wild type in the case of salt treatment,and the DAB staining was deeper,the content of H2O2 was higher,indicating that AtCa N2 gene and At CaN1 gene play a negative role in controlling salt stress response,their overexpression makes plants more sensitive to salt stress.Since atcan2 mutants and atcan1 mutants showed strong tolerance to salt treatment,we obtained homozygous mutants of AtCa N2 and AtCa N1 genes by artificial hybridization,suggesting that they had stronger resistance.We would like to study them further to understand the mechanism of Arabidopsis Ca²⁺-dependent nuclease gene involvement in stress response.