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

Abstract:

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.