Cloning And Prokaryotic Expression Ana Lysis Of Two SOD Genes CsCSD1 And CsFSD2 In Cucumber

Superoxide dismutase（SOD）genes are widely found in the plant community and play a crucial role in defense to abiotic stress.Cucumber belongs to Cucurbitaceae and has high economic benefit.Under adverse conditions,the yield and benefit of cucumber will be reduced,so improving the stress resistance of cucumber is the key research direction.In order to explore the effect of cucumber SOD gene on plant resistance,a bioinformatics analysis of superoxide dismutase gene family of cucumber was made using North China cucumber type 9930 as research material in the paper;the characteristics of superoxide dismutase gene in cucumber were analyzed;the expression of CsCSD1 and CsFSD2 gene was analyzed by fluorescent quantitative PCR under stress,and the prokaryotic expression vector pET32a-CsCSD1 and pET32a-CsFSD2 was constructed,the stress resistance of the CsCSD1 gene was analyzed by prokaryotic expression system.The main results were as follows:1.We identified eight superoxide dismutase genes in the cucumber genome,including five Cu/Zn SODs,two Fe SODs and one Mn SOD gene;Analysis of gene structure and motif showed that most SOD genes had relatively conserved exon/intron alignment and motif composition;2.The expression characteristics of superoxide dismutase gene in cucumber were as follows:most superoxide dismutase genes were expressed in all tissues,the expression of CsCSD1 was relatively higher,the expression of CsCSD2 was relatively low.The expression analysis of CsCSD1 and CsFSD2 under six stress treatments,including ABA,cold,heat,H₂O₂,salt and PEG,showed that the expression of CsCSD1 increased significantly under ABA and salt treatment,and the expression of CsFSD2 increased significantly under six stress treatments;3.CsCSD1 and CsFSD2 genes were cloned in this paper,and the prokaryotic expression vector pET32a-CsCSD1 and pET32a-CsFSD2 was successfully constructed and highly expressed in BL21.Prokaryotic expression analysis showed that the optimum concentration of bacterial solution was OD₆₀₀=0.6,the best induction time of bacterial solution was 4h,the optimum IPTG concentration of bacterial solution was 1 mmol/L;4.The results of stress resistance of transformed E.coli showed that CsCSD1recombinant protein improved the stress resistance of E.coli under different stress treatment.