Study On Tobacco Etch Virus Against Maize Dwarf Mosaic Disease

Maize Dwarf Mosaic Disease is a kind of serious virus disease in corn production. It occurs in the corn producing areas all over the world. For such a long time, it decreases the yield and quality of corns. In our country, since the first report of Maize Dwarf Mosaic Disease in Xinxiang city of Henan province in 1968, it has been happening in north and northwest China in a large scale. The loss of corn yields is between 20% and 80%, which is a principal problem of our corn production. Based on the cloning of genes of SCMV CP, the article introduces cross protection between SCMV and TEV in potyvirus, which develops a new idea of plant virus control.Genes of CP of SCMV are cloned from Shaanxi province(DQ846832). The nucleotide and amino acid homologies were 99.79% and 100% compared with SCMV from Zhejiang province, and 50.64%, 69.65%compared with TEV from Shaanxi province, respectively. In the net house, maize were firstly inoculated with 10%TEV ,and 7 days later inoculated with 10%SCMV in treatingⅠ.Their leaves are rather smooth, and colours are equitable. There are only 13.8% maize turn chlorosis while CK plants are all outbreak for ten days. In treatingⅡ,maize are inoculated with 10%SCMV (CK).Their little heart leaves turn chlorosis in the early days, and present typical symptoms of maize dwarf masaic disease later. TreatingⅢwere inoculated with 10%TEV ,and there is no sympotom. TreatingⅣwhich are inoculated with none of the virus grow healthily. In addition, there is a significant difference between pre-inoculated plants and plants without pre-inoculation as regards the plant height, leaf length and leaf width.We detect with PCR, and find that maize inoculated with SCMV has a 1.1kb fragment——the gene of SCMV CP. The fragment can also be detected in maize of treatingⅠ, but it is rather weak. While the plants inoculated with none of the virus and distilled water present no specific amplification band.Real-time PCR are used to detect the cross-protection effect furtherly. Take maize inoculated with SCMV as referential factors, Normalized SCMV CP amount relative to 18S rRNA,"2-△△Ct"equal to 1. The relative quantity of SCMV in maize of the treating was"2-△△Ct". The relative quantity of SCMV in maize of treatingⅠwas 0.1134 50 days after challenging inoculation. It is far more lower than the quantity of plants inoculated with SCMV only. Generally speaking, there exists a cross-protection between TEV and SCMV. We can decrease the loss of maize dwarf mosaic disease making use of TEV.