| Pleurotus tuoliensis,is the only precious edible fungus with independent intellectual property rights and clear origin in China.Because of its clean white,fat,delicious nutrition and high health value,it has been industrialized and has great development potential.In Xinjiang,bacterial brown rot of P.tuoliensis occurs commonly in the main producing areas of P.tuoliensis,and the incidence rate reaches more than 90 % when it is serious,which brings great obstacles to the production of P.tuoliensis,seriously affects the economic benefits of mushroom farmers and hinders the healthy development of P.tuoliensis industry.Therefore,the occurrence of brown rot of P.tuoliensis in the main producing areas of Xinjiang from 2019 to 2020 was investigated.It was found that the brown rot of P.tuoliensis was serious in the field,which brought great challenges to the production of P.tuoliensis,and the disease had a trend of spread and aggravation.In this paper,pathogenic bacteria were isolated and identified,their biological characteristics were determined,and effective antibacterial chemicals and resistant varieties were screened,which provided scientific basis for accurate diagnosis and efficient prevention and control of diseases.The main research results are as follows :(1)Identification of brown rot pathogen of P.tuoliensis in Xinjiang.The investigation showed that the incidence of brown rot of P.tuoliensis in Xinjiang was 90 % in the late fruiting stage,and the incidence of individual serious diseases was 100 %,and the yield reduction was20 %-30 %.After investigation and isolation,61 strains of pathogenic bacteria were isolated.After molecular barcode amplification and pathogenicity test,five representative strains with pathogenicity were selected for morphological identification,16 S r DNA sequence amplification and phylogenetic analysis.The host range detection,physiological and biochemical properties determination,initial exploration of infection source and determination of infection site were carried out.The results showed that the pathogen of P.tuoliensis brown rot in Xinjiang was Pseudomonas tolaasii;and the physiological and biochemical reactions of the five representative strains were consistent;Artificial inoculation experiments showed that the strain could infect H.marmureus,A.bisporus,F.velutipes,P.ostreatus,L.edodes,H.marmureus.P.tolaasii can infect cap,fold and stipe of P.tuoliensis,causing brown rot.In addition,it was preliminarily determined that the brown rot infection source of P.tuoliensis was water for mushroom production management and rod culture material.(2)Study on biological characteristics of brown rot pathogen of P.tuoliensis.The results showed that the optimum medium for P.tuoliensis brown rot pathogen was LB,the optimum carbon source was mannitol,the optimum nitrogen source was potassium nitrate,the optimum temperature was 28°C,the lethal temperature range was 51°C～56°C,and the optimum p H range was 7～8.(3)Screening of bactericide for P.tolaasii,a brown rot pathogen of P.tuoliensis.The disease control effect of 20 bactericide was determined and screened by indoor plate antibacterial.The results showed that the antibacterial rate of 32 % zodone ethylicin was 41 %～50 % at the dilution concentration of 150 times,and the antibacterial rate of 46 % sodium dichloroisohydrourate was40 % ～ 62 % at the dilution concentration of 300 times.The bactericidal effect of the two bactericide was obvious.(4)Resistance of different P.tuoliensis varieties to brown rot pathogens.In order to identify the resistance of different P.tuoliensis varieties to brown rot pathogen and screen resistant varieties,20 mycelia of P.tuoliensis varieties and 10 fruiting bodies of P.tuoliensis varieties were selected for resistance identification to brown rot pathogen of P.tuoliensis.The test results showed that there was a certain correlation between mycelia resistance identification and fruiting body resistance identification of fruiting body resistance.A total of hypha resistance and 2 strains with immune fruiting body were obtained,which laid a foundation for the resistance breeding of P.tuoliensis to brown rot pathogen. |
