Effects Of 5‐azaC Treatment Seeds And Genomic DNA Methylation Of Maize

It is generally known that maize is a type of crop used as food, fodder and industrial materials and plays an essential role in national economy development. Improvement of maize breeding technology has significant effects on the breeding of new varieties with high quality. The research of maize genomic DNA methylation is an important part in epigenetics. Methylation inhibitor 5-aza C used in the medical field has been applied in agricultural gradually and prominently in recently past years. In this study, maize inbred line B73, used as the experimental materials, which were treated by different concentrations of 5-azacytidine. Analyses of morphological changes and impacts on physiological indexes have been carried out within the stages of seedling, elongation and tassel. In addition, genomic DNA methylation levels were measured and the change of methylation pattern was studied. Results as follows:1.5-aza C affects the germination of B73 seeds. When the concentration between 1μmol/L~10μmol/L, it will have a promotion to germination rate and potential of B73 seeds. 1.when the concentration between 1μmol/L~10μmol/L. On the contrary when the concentration more than 10μmol/L, it will begin to inhibit the germination rate of seeds, as the concentration increasing, the inhibiting effects will be more stronger.2.5-azacytidine affects the tassel stage of maize. As the concentration of 5-azacytidine increasing, the tassel stage of maize decreases in the first, then begin to increase. When the concentration of 5-azacytidine between 1μmol/L-10μmol/L, it has an obvious influence on shortening the tassel stage of maize comparing with the control group, but it will make the tassel stage of maize longer if we use high concentration of 5-azacytidine to deal with maize seeds between 100μmol/L-1000μmol/L.3.5-azacytidine affects the tassel stage and elongation stage of maize’s stem diameter. On the elongation stage, with the concentration of 5-azacytidine increasing, the stem diameter increases in the first,then begin to decrease. When the concentration of 5-azacytidine reach to 10μmol/L, the maize’s stem diameter is the biggest one. On the tassel stage, with the light concentration of 5-azacytidine(1μmol/L-10μmol/L),stem diameter keeps increasing, when the concentration of 5-azacytidine keeps increasing, the maize’s stem diameter will no more increasing.4. 5-azacytidine affects the germination of B73 plant height within the stages of seedling, elongation and tassel. The growth and development of maize were promoted under the concentration of 5-azacytidine(1μmol/L~50μmol/L). The growth and development of maize were inhibited under the concentration of 5-azacytidine(100μmol/L~1000μmol/L).5. 5-azacytidine affects the activity of superoxide dismutase(SOD), with the concentration of 5-azacytidine increasing the activity of superoxide dismutase(SOD), peroxidase(POD) and catalase(CAT) in leaves of B73 increase in the first then decrease within the stages of seedling, elongation and tassel.6. 5-azacytidine affects the content of soluble protein and soluble sugar. Within the seedling, elongation and tassel stage soluble protein content increases in the first then increase. The soluble sugar content have same situation with soluble protein in the tassel stage but opposite in the seedling and elongation stage.7. 5-aza C affects methylation level, with concentration increasing CG methylation level decreases first and then increasing in the elongation stage, but CG methylation level of experimental group was lower than that of the control group. CHG methylation level change had no regular trend. CG+CHG total methylation level of experimental group was lower than that of control group. CG, CHG and CG+CHG total methylation level of B73 genomic DNA decreased in the tassel stage under the treatment of 5-aza C with different concentrations.8. 5-aza C affects methylation level of CCGG locus of B73 genomic DNA. CG hypo methylation level was lower than hyper methylation level and CHG hypo methylation level was higher than hyper methylation level in seedling stage. CG hypo methylation level was lower than hyper methylation level and CHG hypo methylation level was higher than hyper methylation level in elongation stage. CG hypo methylation level was higher than hyper methylation level and CHG hypo methylation level was higher than hyper methylation level in tassel stage.