Studying On Finding New Method For Eradication Pathogen Of Citrus Tristeza Virus And Citrus Tatter Leaf Virus

As the creage of citrus has expanded each year, the production increased year by year, but there is also an increasing trend of the citrus disease. Because the long-term agamogenesis in the production process, the citrus is often susceptible to one or several viruses or viroid,which is the key limiting factors to the citrus industrial development. This study focus on detoxification infection of several citrus viruses of citrus seedlings in order to find rapid and efficient detoxification methods for the production of non-virus citrus seedings. The parent material of citrus with CTLV and CTV, conserved in net room of detoxification center site, Huazhong Agricultural University.The experiment is generally divided into four parts. In the first part, we used shoot-tip grafting and thermotherapy methods to detoxificate CTV from citrus:Chuhong pomelo (Citrus grandis osback cv.Chuhong), Feicui pomelo (Citrus grandis osback cv. Feicui), Daoye mandarin (Citrus unshiu Marc cv. Yinba), Shibben mandarin (Citrus unshiu Marc cv. Shibben), and Jiangxi mandarin orange (Citrus unshiu Marc). The reverse transcriptase PCR (RT-PCR) were used to test the results. The results show that with thermotherapy and shoot-tip grafting methods it can detoxificate CTV from Jiangxi mandarin Daoye mandarin, Shibben mandarin, Chuhong pomelo and Feicui pomelo.In the second part, we only used thermotherapy method to detoxificate CTV but failed. The results were tested by reverse transcriptase PCR (RT-PCR) and dot bloting.In the third parts, the botanical agents (Chinese herbal medicine) A and B were used combined with the traditional detoxification method thermotherapy. The extracts were applied every 5 days for 80 days. The citrus seedlings were considered virus-free with negative reactions of RT-PCR,and leaves were sampled 1 day,3 days,5 days,7 days,9 days after the completion of the treatments to determine the activity of resistance-related enzymes PPO, POD, and SOD, and the esults showed that PPO, POD, SOD activity were all increased after treatment compared with the control.In the fourth parts shoot-tip grafting method were used combined with the botanical agents (Chinese herbal medicine) A and B.The results were tested by RT-PCR and showed that this methods can detoxificate CTV and CTLV from citrus seedings.