Study On Pathogenicity And Genetic Diversity Of Plasmopara Viticola

Grape Downy Mildew is one of the most important conditions affecting grape growth,which was first introduced in North America in the 1930 s.The earliest appeared in 1899.The cause of this condition is Plasmopara viticola,which has a significant effect on the quality and yield of the grapes after the onset of the disease.This article mainly aims at the occurrence of disease and the factors such as climate and so on,so as to provide an important basis for the treatment of the disease.At the same time,the collection of Hunan,Jiangxi and Fujian provinces The results showed that the pathogenicity of the different grape varieties and the size of sporocysts were analyzed,and the genetic diversity of the spores was analyzed.Diversity research.(1)Twelve isolates with grape downy mildew were selected from the three provinces,and 19 strains were tested for the pathogenicity of five different grape varieties by in vitro leaf inoculation.,According to the study found that the geographical differences are different from the pathogenicity,according to the data show that from Pingxiang Luxi(PXLX)strains of the most pathogenic bacteria,derived from Hengyang Hengshan(HYHS)strains of pathogenicity of the most weak.(2)Twenty-four strains were subjected to PCR amplification by ITS column,β-tubulin sequence and CytB sequence primers.The target bands of 790 bp,560bp and 400 bp were obtained.After sequencing,phylogenetic trees were established to study their genetic characteristics.The study found that there are four places in Hunan Province,the genetic relationship is very close,Xinyu,Pingxiang and Nanchang strains also showed a special genetic relationship.However,some strains did not show affinity.However,the CytB gene sequence has the highest ability to discriminate,and it is the most efficient at the time of classification,and it can also be shown in the case of isolating the strain with closer genetic relationship.powerful functions.(3)The occurrence of downy mildew could affect the structure and composition of bacterial community.In this paper,the OUT of the bacterial communities in the leaf surface of downy mildew were classified and analyzed in the classification of the door,the class,the family,the genus and the species.The results showed that,at the level of species,37.79% of the species are non annotated strains.So we choose the level of genus analysis,without the disease leaves was the highest content of Acremonium(Nectriaceae).The highest content of the leaf was Xanthomonas sp.(Xanthomonas),and the average content of the genus was 27.77%.The results of Alpha diversity analysis showed that the richness and evenness of bacterial population structure were not lower than that of leaf.The reason may be due to the occurrence of a large number of open wounds after the onset of grape downy mildew,not only weakened the disease resistance of grape downy mildew,but also conducive to the colonization of saprophytic bacteria and other environmental microorganisms.