Screening, Identification And Application Of Biocontrol Strains Against Solanaceae Bacterial Wilt Caused By By Ralstonia Solanacarum

Solanaceae plants bacterial wilt, caused by Ralstonia solanacarum, is a disaster plant disease. To effectively develop biocontrol microorganism resources against this disease, the main biological characteristics of the endophytic bacterial strains isolated from the stems of the different health solanaceae plants in endemic areas of solanaceae plants bacterial wilt and their antagonistic activity and performance against R. solanacarum were systematically studied in the paper.The main result of this research as follows:(1) Isolation, purification and identification of endophytic antagonistic bacteria156endophytic bacterial strains were isolated from some healthy stems in seriously R. solanacarum-infected fields at Yongzhou, Chenzhou and Yongshun regions of Hunan by the dilution method.29strains among the above346ones against R. solanacarum were screened by the antagonistic test, which the strains with antagonistic effect accounted for8.38%. Further, B09、C27、F1among29strains with antagonistic effect were best, which their radii of inhibtion zone against R. solanacarum for24hours were6.5mm,7.0mm and6.5mm, respectively. Based on analysis of morphological, physiological, biochemical characteristics and16S rDNA phylogeny, strain B09, C27and F1were identified as Klebsiella oxytoca, Bacillus amyloliquefaciens and Bacillus mojavensis, respectively. The accessions of them in GenBank were JF901758、JF901759and JF901760,respectively.(2) Biological character and antimicrobial spectrum of three srtainsThe growth of B09strain required strict temperature. And its optimal growth temperature was28℃. But the optimal growth temperature of strain C27and F1were30℃The growth of three strains were affected on pH. The optimal growth pH of strain B09、 C27and F1were7.5,7.0and7.5, respectively.Strains B09and F1could grow with carbonic sources of glucose, mannitol, arabinose, sucrose and rice flour. Also they could grow with five kinds of organic nitrogen, and inorganic nitrogen contained in KNO3, casein and ammonium chloride could not be used for them. However, the carbon and nitrogen utilization capacity of C27were different from B09and F1strains. Strain C27could grow with carbonic sources of sucrose, D-fructose, D-galactose, α-lactose, glucose, maltose, mannitol, citrate and rice flour. It could also grow with nitrogen sources of beef extract, peptone, soybean powder, tryptone, yeast extract and potassium nitrate. The nitrogen of casein and ammonium chloride could...