Fengycin-producing Bacillus subtilis alleviate strawberry fusarium wilt disease by activating microbial community...

Fusarium wilt, caused by Fusarium spp., has become the most severe destructive fungal pathogen that limits strawberry crop production. Currently, biological control can effectively control the occurrence of Fusarium wilt, but the effectiveness mainly depends on the type of bacterial strain. In this paper, a Bacillus subtilis (SF17) was isolated from the rhizosphere soil of healthy strawberries, and its control effect on Fusarium wilt disease was reaching as high as 74.51 %. The SF17 can produce amylase, cellulase, siderophores. However, it is currently unknown how SF17 inoculation secretes antibacterial active substances and regulates soil microbial communities to achieve disease resistance. We used metabolite profiling combined with high-throughput sequencing to evaluate the effects of B subtilis (SF17) on infested soils. The SF17 can produce Fengycin (antibacterial substance), which has an inhibitory effect on Fusarium. Moreover, the SF17 treatment reduced the relative abundances of soil-borne pathogens of the genera Mortierella, Colletotrichum, Botryotrichum, Alternaria, and Fusarium and increased the relative abundances of the potentially beneficial microorganisms of the genera Sphingomonas, Bacillus, Sphingobium, Mesorhizobium, Lysobacter, Bradyrhizobium and Trichoderma in the soil. Particularly, SF17 can promote the growth of Streptomyces and Pseudomonas, which has an inhibitory effect on Fusarium. SF17 increased the relative abundance of functional genes involved in the carbon fixation and oxidative phosphorylation, carbohydrate metabolism and amino acid metabolism pathways, while reduced the relative abundance of genes related to glycan biosynthesis and metabolism associated with disease occurrence. In summary, SF17 enhances plant disease resistance by producing Fengycin antibacterial substances and recruiting beneficial microorganisms in the rhizosphere, providing important reference for the biological control of vegetable soil borne diseases.