Detection And Analysis Of Cucumber Green Mottle Mosaic Virus In Watermelon

Cucumber green mottle mosaic virus (CGMMV) is one of the most important virus diseases in cucurbits. Once infected with CGMMV, the fruits of watermelon, cucumber, muskmelon et al will appeared very serious symptoms and lost economic values, In fields, CGMMV caused yield reduction to crop failures, or even total crop failure. Through the field investigation of May,2011, we found some watermelon plants in Shaoyang County which seems infected with CGMMV. And the RT-PCR detection shows that the watermelon plants was truly infected with CGMMV. In order to analysis the source and transmission of CGMMV in Hunan province, we detected rootstock seeds with RT-PCR which sold in Hunan Province, but produced in Turpan Xinjiang, Zhangye Gansu, Yulin Shanxi, Changde Hunan Province,2011, and made a bioinformatics analysis of the nucleotide sequences. The innovations and results are as follows:(1) Using RT-PCR detection for the first time proved that CGMMV appeared in watermelon of Hunan province. We made a comparison of nucleotide sequences between CGMMV-SY isolates and CGMMV-JX isolates, and think about producing area of "Jingxin stock king", we speculate that the CGMMV occurred in watermelon in Hunan, may be originally transmitted by drafting with rootstock infected with CGMMV.(2) A pair of CGMMV-specific primers is designed to help establish a RT-PCR detection method on CGMMV in seeds. Preliminary established a rapid detection system for CGMMV in seeds. This method can provided quarantine departments some reference for the rapid detection of CGMMV in germplasm resources.(3) For the first time to detected the rootstock seeds which produced in Turpan Xinjiang, Zhangye Gansu, Yulin Shaanxi and Changde Hunan with RT-PCR, and the results show that:detection of rootstock sample exists not only with CGMMV, and have a very high infection rate. The results further verify the grafted rootstock propagation CGMMV hypothesis, provide certain reference value for the planting and control of watermelon crop. What’s more, the detection confirmed that the cucumber green mottle mosaic virus has spread to Xinjiang and Shaanxi Province.(4) For the first time to make bioinformatics analysis of CGMMV isolates in the different Rootstock seeds. The analyses of CP and MP gene sequences of CGMMV isolates from Turpan Xinjiang, Zhangye Gansu, Yulin Shaanxi and Changde Hunan show that:7of the8nucleotide sequences shared100%identities, and only had4base difference compared with CGMMV-HunanCDl isolate. Using nucleotide sequences of CP gene and MP gene to construct phylogenetic trees, the trees support that CGMMV-SY was finely come from South Korea. We can also find that the outbreaks of CGMMV in China may come from different countries and regions from Asia, spread to China by seed introduction. This may provide a reference value for the study of occurrence and spread of CGMMV in our country. The nucleotide sequence of CGMMV formation in the study of translation of The hydrophobicity, spiral, and phosphorylation sites predictions of amino acid sequence has important reference value to the further study of the structure and function for CP protein and MP protein.The study includes researches on the detection and transmission of CGMMV: For the first time, discovered watermelon of Hunan, rootstock seeds of Xinjiang and Shanxi were infected with CGMMV by RT-PCR; Designed a pair of CGMMV-specific primers and establish a rapid, batch RT-PCR detection method of CGMMV in seeds. This research can provided quarantine departments some reference for the detection of CGMMV in germplasm resources. The primer and methods has gained the national invention patent.