Bacillus Methylotrophicus CSY-F1 Allevates The Drought Stress Of Cucumber Seedlings And Function Analysis Of One Differentially Methylated Cucumber Gene

With the continuous growth of the world's population,the security of food will be more and more important.Climate change which is main anthropogenic factor results the reduction of global crop productivity.In all abiotic factors,drought stress is one of the key constraints to plant growth.Cucumber is one of the most widespread vegetables in the worldwide.It has large leaves,shallow root distribution and the demand of the high humidity so that it's sensitive to water stress.It's necessary for vegetables with high water requirement to investigate how to reduce the damage of drought stress.In this study,the strain CSY-F1 of Bacillus methylotrophicus was inoculated into the FA-contained cucumber-planted soil to investigate whether CSY-F1 enhanced the drought tolerance of plants not only under the FA-uncontaminated environments but also under the FA-contaminated conditions.we detected the activities of soil enzymes(alkaline phosphatase,urease,sucrase and CAT),the levels of soil polysaccharides,the activities of antioxidant enzymes(SOD,CAT,APX,DHAR,GR,GPX,and MDHAR)and antioxidant(AsA and GSH)in cucumber,the contents of soluble sugars and proline in leaves,and the expression levels of drought response genes in seedlings.We investigated the influence of PHBA on the changes of cucumber genomic DNA methylation under the heat stress.We got some differentially methylated DNA sequences by using technology of MSAP.Then the differentially methylated DNA sequences were cloned and analyzed for the homology.We got expression quantity of one differentially methylated gene in the different parts of the cucumber under the different treatments by using the fluorescent quantitative PCR.The location of the gene expression was confirmed by using subcellular localization.We got transgenic cucumber by using tissue culture and transgenic arabidopsis by using the floral dip method.Typical results are shown below.(1)The strain CSY-F1 increased the levels of soil polysaccharides,elevated the activitiesof some soil enzymes such as phosphatase,urease,sucrase and CAT and antioxidant enzymes such as SOD,CAT,DHAR,MDHAR,GR,APX and GPX in cucumber,enhanced the contents of soluble sugars and proline in leaves,and activated the expression of some drought response genes in seedlings,thus alleviating the drought stress of cucumber whether in the FA-contaminated soil or not.(2)We analyzed the methylated DNA of cucumber by using technology of MSAP.We found the influence of PHBA on the changes of cucumber genomic DNA methylation under the heat stress.We found the expression quantity of one differentially methylated gene was changed in the different parts of the cucumber under the different treatments.PHBA improved the expression quantity of Csa010600 under the heat stress.The location of the gene expression was confirmed by using subcellular localization.The differentially methylated gene were cloned and we got transgenic cucumber by using tissue culture and transgenic arabidopsis by using the floral dip method.