| The antagonistic strains of Rhizoctonia solani causing Rhizoctonia solani were selected from buckwheat soil to enrich the antagonistic Seed Bank of Rhizoctonia solani,and provide strain resources for the follow-up inhibition mechanism research and the development of related biological control agents.PDA and LB culture medium were used to screen soil single colony.Using Rhizoctonia solani as antagonistic target strain,antagonistic strains were selected by antagonistic culture;morphological,physiological and biochemical characteristics were used for strain identification,Further use of molecular biology.16 S r DNA sequence was determined.Through blast comparison.The antagonistic strains were selected.The prevention and control effect of buckwheat was observed and the inhibition rate was calculated indoor.Through the detection of fermentation metabolites of antagonistic strains,the antagonistic substances were speculated and analyzed.The results showed that: six strains(named LKSFJ1,LKSFJ2,LKSFJ3,LKSFJ4,LKSFJ5,LKSFJ6)with antagonistic activity against Rhizoctonia solani were screened from buckwheat rhizosphere soil,and their inhibition rates were 49.00%,47.91%,63.68%,59.35%,56.72%,61.81% respectively.According to morphological characteristics,physiological and biochemical identification and 16 S r DNA identification,strains LKSFJ1 and LKSFJ2 were Paenibacillus polymyxa strain;strains LKSFJ4 and LKSFJ6 were Bacillus subtilis strain;strains LKSFJ3 and LKSFJ5 were Bacillus amyloliquefaciens strain The control effect test showed that strain lksfj3 could antagonize 76.87% of Rhizoctonia solani infection of buckwheat and promote the growth of buckwheat seedling roots.The measurement results of the fermentation metabolites of the strain LKSFJ3 showed that the metabolites of the antagonistic strain consisted of polypeptides,organic acids,nucleic acids,vitamins and coenzyme factors,steroids,lipids,carbohydrates,hormones,transmitters,and antibiotics. |
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