Identification And Separation Of Antifungal Protein From Bacteria Against Alternaria Brassicae

Black spot disease, a common disease seriously affecting Chinese cabbage growth, is caused by Alternaria brassicae which damages blades even the whole plant and spreading rapidly with seed transmission.Although there are abundant of studies on the pathogenic bacteria, disease resistance and control of black spot disease both at home and abroad, Disease-resistant varieties and chemical pest control are still the main ways for prevention. Following the thriving of environmentally friendly agriculture, biological control like screening the antagonistic microbe with the help of biotechnology is a new potential approach attracted great attention.This paper aims at screening a bacterial strain with the ability of interfering with Alternaria brassicae from the rhizosphere, offering clone theory by isolating, purifing and sequencing the antagonistic protein. This will provide a new biological strategy for the prevention of Black spot disease.LBC-1 is one that producing antimicrobial peptide screened from vegetable field. It was a producing bacteria Bacillus which had antagonistic activity and relatively small antibacterial range to some extent. The antagonistic protein it produces can highly interfer with Colletotrichum gloeosporioides,Fusarium oxysporum,Fusarium moniliforme Ceratosphaeria phyllostachydi.Physiological and biochemical test indicated that LBC-1 showed a great similarity with Bacillus amyloliquefaciens. Comparing the sequence of 16S rDNA with those in NCBI website and drawing phylogenetic tree with the help of Neighbor-Joining, it showed that sequence homology rate was as high as 99.03% between the sequence of LBC-1's 16S rDNA and that of AB325583 (Bacillus amyloliquefaciens) in the data bank.In order to enhance the amount of antagonistic protein and spore the Bacillus amyloliquefaciens LBC-1 produced in fermentation, we screened the carbon and nitrogen sources and inorganic salts the culture medium needed as well as optimizing the components and the fermentation condition by means of orthogonal test method. This will lay a basis for the follow-up industrialization.