A Preliminary Study On The Mechanism Of Resistance To Verticillium Wilt In Transgenic OXO Arabidopsis Thaliana

Cotton verticillium wilt is a kind of soil-borne fungus vascular disease;it is one of the most destructive diseases of cotton.Verticillium wilt seriously affects the process of cotton growth and development and can cause a significant reduction in cotton production and fiber quality decline,so it is also known as cotton "cancer." Currently methods used for the prevention and treatment of Verticillium wilt are mainly chemical fumigation,rotation and so on.However,there are some limitations about these methods.Therefore,Using genetic engineering technology to cultivate transgenic cotton varieties is of great significance.In this study,we used this as the starting point to study the resistance of transgenic Arabidopsis thaliana to Verticillium wilt from various angles.The transgenic plants are got through the method of floral dip.The results of this study are as follows:1、We verify the transgenic plants using the method of GUS Staining and PCR and we get the transgenic lines that can stably express the exogenous gene.2、By inoculating suspension spore of Verticillium,we tested the resistant levels of the transgenic plants.Four-week-old A.thaliana were inoculated by root dipping with spore suspensions（1×107spores ml-1）.14 days after inoculation（DAI）,the WT plants displayed obvious disease symptoms,with many wilted leaves arising from the bottom of the plants.Meanwhile,the transgenic plants with fewer withered leaves showed greater tolerance to Verticillium than did the WT plants3、The significant changes were found about antioxidant enzyme activities of transgenic plants when comparing with WT after 48 hours inoculation.After 48 hpi,both of the transgenic plants and the wild type plants showed decreased SOD activity.However,the activity of SOD of transgenic plants decreased by 15.7%while the wild type up to 46.7%.The activity of CAT of WT plants decreased by 16.6%,while the transgenic plants show no difference comparing with control.After 48 hpi,the transgenic plants showed increased activity of POD and PPO.The activity of POD and PPO of transgenic plants increased by 42.9% and 64.9%,respectively.While the activity of POD and PPO of the WT only show rise slightly.4、We tested the expression of PAL in WT and transgenic plants respectively after 48 h inoculation.The results show that the expression level of PAL1 and PAL2 in transgenic plants increased by 384% and 260%,respectively.While the WT plants only shows slightly increase.5、We tested the amount of H₂O₂ of both WT and transgenic plants after 48 h inoculation using the method of DAB Staining.We found the transgenic plants can accumulate more H₂O₂ than WT.6、We tested the amount of lignin of both WT and transgenic plants.The results show that the transgenic plants can accumulate more lignin than WT.