Molecular Detection And Identification Of Several Viruses Inefcting Horticultural Plants

In recent years, along with the vegetable acreage expanding and the cultivation methods constantly updating, the virus disease occurs seriously, and most of them showed a mixed infection. It has become the main factors restricting the crop yield and quality.Tomato yellow leaf curl virus (TYLCV), causing tomato yellow leaf curl disease, is a devastating disease of vegetable production. Cucumber green mottle mosaic virus (CGMMV) is one of the important virus diseases of cucurbits. The virus will often make the infected crop harvest, which poses a serious threat to cucurbit crops production. These two kinds of viruses studied in this research were detected in the major tomato or cucurbitaceae growing areas in China in order to investigate their distribution and host range based on PCR or RT-PCR technology and analysis their sequence variability from different sources. The main conclusions are as follows:1. Through to detect833seedlings of the five major seedling companies in Shandong province, the infection rate of seedling was0.12%.2. Field surveys were carried out in the major tomato growing areas of Shandong, Jilin and Liaoning Province in China to assess the sanitary status of TYLCV. A total of359tomato samples were collected from three provinces described above, and206tomato samples were confirmed the presence of TYLCV, and the45complete sequence of TYLCV were obtained in this study.3. The TYLCV host range was identified initially.12families and over32non tomato plant samples were collected from3provinces, and finally found the Zinnia elegans, Gossypium spp, Abutilon theophrasti, Nicotiana tabacum, Acalypha australis, Vignasesquipedalis and Perilla were revealed the presence of TYLCV. In addition to Acalypha australis, the other6plants mentioned above were new hosts that have no relevant report in the world. Sequence analysis revealed that isolates from the new hosts shared high sequence similarity (92.0%-99.8%) with TYLCV isolates registered in GenBank, and all of them were belonged to TYLCV-IL strains.4. The occurrence and distribution of CGMMV has been investigated clearly in Shandong Province.324Cucurbitaceae samples were collected from12regions, and142of them were infected by CGMMV, the infection rate achieve to43.4%. The complete sequences of CGMMV cucumber, loofah, and muskmelon isolates were obtained. It is the first time to obtain the two complete sequences isolated from loofah and muskmelon in China, and loofah is a new host for the first time in the world. The complete sequence analyses showed that there is no significant relationships between CGMMV phylogenetic and the CGMMV host, but has some correlation with the separation region.5. Currently, the main virus or viroid species infecting peach are:Peach latent mosaic viroid (PLMVd), Hop stunt viroid (HSVd), Apple chlorotic leaf spot virus (ACLSV)...