| Chili is a kind of important vegetables and economic crops, which mainly plant in DongKou county ShaoYang city. Virus disease is the primarily perennial disease on chili, seriously influencing the yield and quality of chili. This study samples and investigates the chili virus disease in the primary chili planting base of DongKou county, ShaoYang city, HuNan provicine. Six major virus were molecularly detected using RT-PCR. Sequencing and analyzing for the part of the viral sequences, we discuss the population and genetic structure that is highest detection rate of virus gene in our experiment. The results are as follows:(1) Chili virus disease was prevalent in dongkou and the field symptoms primarily are patches mosaic, yellowing, low shrinkage and distortion pattern. Using RT-PCR, design-specific primers were applied to detect the 227 samples that have the probability commonly infected by ChiVMV, PVY, BBWV, PMMoV, TMV and CMV. The results show that the higher rate of virus infection was 88.55%.6 kinds of virus can be detected and BBWV 2 have the highest detection rate 37.89%, followed by PMMOV, PVY, CMV, TMV and ChiVMV. Detection rate were 30.84%,29.52%,15.42% and 14.10% respectively. The results can be found that infected virus primarily are BBWV 2, PMMOV and PVY in DongKou county. Moreover, most samples are compound infection, which apply the two compound virus infection combination mode, including BBWV 2+ PMMOV, BBWV 2+ PVY and PVY+PMMOV combination type, etc.(2) After homologous and evolutionary analysis for partial CP sequences, coding in the highest detection rate's virus (BBWV 2, PMMOV and PVY), the results showed that the similarity of BBWV-2 ShaoYang isolate with others range from 83% to 95% and the highest similar isolate is South Korean isolate, Korea K (AF104335.1). PVY and PMMOV ShaoYang isolates' similarity are 99% to 100% and 98% to 99% and the highest similar isolates are Russian isolates Kzn32 isolates Bal-11 (KR816231.1) and Spain (KT962849.1), respectively.(3) the coding regional sequences of BBWV2 dsRNA-2 in NCBI were aligned and analyzed through the phylogenesis, genetic diversity of different virus isolates population, genetic differences between groups of different geographical isolates and the recombinant events in those isolates. Analysis results show that the evolutionary relationships of BBWV2 isolates mainly divides into two clusters (? and ?). And the lager cluster I can be divided into four small clusters. From the point of evolutionary relationships, viral relations were not significantly associated with geography and host. The value of Tajima's D is negative, indicating the population expansion in China and South Korea. However, the Nucleotide diversity was obviously higher than the Haplotype diversity. Genetic differences among the two countries, which have the frequent gene flow, are significant. According to the analysis of recombination, recombinant events of BBWV2 are widespread in natural populations. And some isolates take place the recombinant event in different regions and hosts.This study focuses on the detection of chili virus disease in DongKou county and homology analysis of 3 kind of viral sequences, having highest. The pathogeny of chili virus in this region and the relationship between chili viruses and others were determined. The genetic evolution of the disease and popular situation are clearer, after analyzing the population genetic structure in the highest detection rate virus. It provides a effectively theoretical basis for predicting and controlling the happening of virus disease. |
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