芽胞杆菌BJ-6的鉴定及对甜瓜细菌性果斑病的防治

芽胞杆菌是目前植物病害生物防治研究最多的一类微生物,其在自然界中分布广泛,开发潜力大。【目的】为了探究从杏树根际土壤分离的芽胞杆菌BJ-6的分类地位及其防病促生作用。【方法】本研究测定了芽胞杆菌BJ-6的形态和生理生化特征,通过PCR扩增了该菌的16S rRNA、gyrA和gyrB基因并进行了序列测定,通过多基因聚类分析确定其分类地位,平板对峙法测定抗菌谱,盆栽幼苗实验验证其对甜瓜细菌性果斑病的防治效果和对甜瓜的促生作用。【结果】结合形态特征、生理生化特性及多基因序列分析建立的系统进化树,确定菌株BJ-6为解淀粉芽胞杆菌(B. amyloliquefaciens),抑菌实验发现该菌株对15种植物病原菌均有不同程度的抑菌活性,盆栽实验结果发现该菌株发酵液对甜瓜细菌性果斑病有很好的防治效果,并对甜瓜苗有很好的促生作用。【结论】BJ-6属于解淀粉芽胞杆菌,抑菌谱广,且具有防病促生作用,具有进一步开发为生防制剂的前景。

Identification of Bacillus sp. BJ-6 for biocontrol of bacterial fruit blotch of melon

Bacillus sp. is one of the most studied microorganisms in biological control of plant diseases. It is widely distributed in nature and has great potential in agriculture.Objective] To identify strain BJ-6 and explore its biological control function.Methods] We identified the strain BJ-6 by morphological characteristics, physiological and biochemical tests and 16S rRNA, gyrA and gyrB gene sequence analysis. We measured the antimicrobial spectrum of BJ-6 by antagonistic experiment and studied the biocontrol effects and growth promotion on melon seedlings by pot experiment. Results] We identified strain BJ-6 as B. amyloliquefaciens through the phylogenetic analysis of 16S rRNA, gyrA and gyrB sequences, and the characteristics of morphology, physiology and biochemistry. We found that BJ-6 strain had the bioactivity against 15 plant pathogens by the antagonistic experiment. The fermentation broth of BJ-6 had very good control efficiency to bacterial fruit blotch of melon seedlings in the pot experiment. Pot tests also showed that BJ-6 strain could promote the melon seedlings growth significantly. Conclusion] We identified BJ-6 strain as B. amyloliquefaciens. Due to its broad spectrum of inhibiting plant pathogens and plant growth promoting ability, this stain had a good development value as biocontrol agents in plant protection.