Forcasting, Identifying And Bio-control Bacteria Screening Of Tobacco Wildfire Disease From Guiyang Tobacco Area In Chenzhou

Tobacco wildfire disease is a bacterial disease caused by Pseudomonas syringae pv.tabaci which can endanger leaf,flower,capsule,seed and other parts of plant.It is a common bacterial disease in the major tobacco producing countries in the world,such as USA and Germany,even is fatal.In recent years,the large scale cultivation of flue-cured tobacco without the characteristics of resistance to wildfire disease,single plant variety and other reasons,making the tobacco wildfire disease has become increasingly serious and gradually become a major obstacle to the development of tobacco production in China.To definating occurrence,distribution and damage condition,explore the happened rule of disease and study effective control technology,author carried out the systematic studies of constructing the forecasting model,identifying the pathogen,screening the bio-control bacteria of tobacco wildfire disease in Hunan Guiyang tobacco area.The results are as follows:1.Constructing the prediction model of tobacco wildfire disease in tobacco-growing area of Guiyang,Chenzhou.Using nonlinear SVR and linear SLR methods,we constructed the effectively meteorological forecasting model of the wildfire disease in tobacco area of Guiyang based on the smoky disease index and the corresponding meteorological data from 2012 to 2015.Mainly through the 5 data of relative humidity,maximum and minimum of relative humidity whole point,relative humidity extreme difference and the minimum daily humidity,the cause for the occurrence and prevalence of wildfire could be reflected in Guiyang,and the results supported high temperature and humidity weather is the important condition for the occurrence and prevalence of wildfire in this area.2.Identifying initially the wildfire pathogens in Guiyang as Pseudomonas syringae pv.Tabaci.By indoor separation and purification,the suspected pathogens were screened from the samples of wild smoke from tobacco area in Guiyang.16 S rDNA of the suspected pathogens were blasted in NCBI database,there were 5 strains shared more than 99% similarity with Pseudomonas syringae pv.tabaci.The sample 16GY8-1 had the highest similarity with the standard sample of wildfire,reaching 99.65%,and it was judged that the sample was the pathogen of wildfire in Guiyang tobacco area of Chenzhou.3.Screening bio-control bacteria of the wildfire.The preliminary identification of the antagonism of the selected strains by paper disc method was carried out.The results showed that the 16SF21,16SF33 and 16SF34 from the stem and leaf of the healthy tobacco from the Wulong Village,Aoquan Town,Guiyang County,Chenzhou County,Hunan Province,all formed an inhibition zone on the culture dish.The diameter of the inhibition zone was 6.00 mm,5.50 mm,7.25 mm,respectively.Compared with the other strains with inhibition zone,the antagonistic effect of 16SF34 was the most obvious,therefore and the effect of 16SF34 was the best,the homology of 16SF21 and Bacillus licheniformis,Bacillus subtilis reaches 100%,the homology of 16SF33 and Stenotrophomonas maltophilia reaches 99%,the homology of 16SF34 and Bacillus subtilis also reaches 99%.The results of this paper could provide new idea and reference for predicting tobacco wildfire,identifying pathogens and screening bio-control bacteria in Chenzhou.