Molecular Phylogeny Of CMV And TuMV And The Transmission Efficiency By Myzus Persicae Fed On Con A

Myzus persicae (Sulzer) is polytrophic pest, its summer host crops are mainly cabbage, radish, turnip, mustard, canola, turnips, bell pepper, chili, spinach and so on many kinds of vegetable crops, and it's the main vector transmitting virus. Turnips Mosaic Virus (TuMV) is one of the most important members in Potyvirus, and also is important pathogenic viruses to cruciferous vegetables in our country. TuMV is transmitted by 89 species of aphids including the peach aphid (M. persicae) and cabbage aphid (Brevicoryne brassicae) in a non-persistent non-circulative manner. Except aphids can transmit TuMV, it can also transmitted by mechanical way. Especially, the numbers and time in peak of flight of alate aphids will influence virus transmission more. Cucumber Mosaic virus (CMV) is one important virus damaging vegetable plants, and also one typical member of Cucumovirus in Bromoviredae. CMV has wide host range almost 1000 plants in 85 families and can transmitted by 86 species of aphids including M. persicae, Lipaphis erysimi (Kaltenbach), Aphis gossypii in non-persistent way. The efficiency of virus transmission is influenced many kinds of factors, such as aphids species, plant species and so on. This paper mainly studied molecular characterization and genetic of TuMV and CMV's capsid proteins which is very important in virus transmission mechanism, and also influence on efficiency of virus transmission of two kinds of viruses by peach aphid. The main result as follows:1 Establishment of virus detection and molecular detection methods of CMV and TuMV43 samples collected from the field including Brassicaceae, Cucuarbitaceae, Solanaceace from Beijing and Shandong province which extracted RNA from and detected by RT– PCR to know which virus (TuMV or CMV) they belong to (table 3). Electrophorogram showed that clear bands appeared around 1000bp and 650bp, and they are the same with expectations. In all samples, for TuMV about 28 cases, around 65.9%, five CMV isolates, about 12.2% (subgroup I), 1 case infected with TuMV and CMV. Then rapid detection of CMV and TuMV are established, which provide feasible method to monitoring and precontrol virus disease. 2 Phyletic evolution and molecular variation of CP gene of CMVThe overall pairwise sequence identity of 5 isolates with members of subgroup II is lower at both nucleotide and amino acid sequence levels than subgroup I, as well as their position generated in the phylogenetic trees, revealed that the 5 isolates belongs to subgroup I . The overall higher degree of homology exhibited at the amino acid level between all the strains, but sequence analysis of CP at the amino acid level reveal that there are many positions where amino acid shows diverse effect compared to others isolates used in the study, especially amino acid 25 (Pro to Ser) may make different from strains in aphid transmission. Therefore rapid rapid detection method of molecular variation and phyletic evolution of CMV was established, and also the result surveyed genetic structure and diversity of CMV on vegetable plant from Beijing and Shandong.3 Phyletic evolution of CP gene of TuMVResults were dealed with Neighbor-Jioning method to construct phylogenetic trees of TuMV. Results showed that there are 6 cruciferous plants, 14 solanaceae plants, 8 gourd family plants in 28 TuMV isolates of Beijing and Shandong, and all of them belong to world - B group. All cruciferous plants all belong to Brassica. Research shows that TuMV harm vegetable crops, high Infection rate. Through molecular fast detection of TuMV, it is better to know frequency of TuMV virus and to provide reliable measures for disease prevention and control.4 Effect on virus transmission by M. persicae affected by Con AAphids with virus fed on artificial diet containing Con A, then move them to healthy plants. After 10d later, virus symptoms showed on plant leaves, just like slight deformity on leaves, thick leave, shrinks and ring spots on leaves, and leaves turn yellow, mosaic symptoms appear, veins. It showed aphids carried virus after feeding diet containing Con A still have ability to transmit virus. With artificial diet containing Con A, the results showed that different effects of Con A to virus transmission by aphids depend on variety of plant viruses. The analysis of experiment showed lectins of ConA have inhibitory action on TuMV transmission by peach aphid with virus, but for CMV transmission is not significant.