C17-fengycin B, produced by deep-sea-derived Bacillus subtilis, possessing a strong antifungal activity against Fusarium solani

Root rot disease caused by Fusarium solani is the most devastating disease of the tomato and legume crops in China. The metabolites of Bacillus species can inhibit many fungal diseases. In this study, the metabolites of deep-sea-derived bacterium Bacillus subtilis 2H11 can significantly inhibit the growth of F. solani. The metabolite C-17-fengycin B, one of the cyclic lipopeptides, was identified by the combination of silica column chromatography, high-performance liquid chromatography (HPLC), high-energy collision induced dissociation mass spectrometry (HCD-MS) and tandem mass spectrometry (HCD-MS/MS). The results of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that C-17-fengycin B could destroy the structure of the hyphae and spores of F. solani. The antifungal activities of C-17-fengycin B against F. solani were tested at concentrations ranging from 0.05 mg/mL to 0.20 mg/mL. The results indicated that C-17-fengycin B inhibited the growth of F. solani with antifungal index of 89.80% at 0.20 mg/mL, and the antifungal activity of C-17-fengycin B was further verified by the pot experiment. In addition, the cytotoxicity experiment showed that C-17-fengycin B had good biocompatibility and was a potential candidate for the development of biocontrol pesticide in the future.

Automated summary

The metabolites of Bacillus subtilis 2H11 from deep-sea sources, especially C-17-fengycin B, showed significant inhibitory effects on the growth of fungal pathogen Fusarium solani in tomato and legume crops. The study used various methods to confirm the antifungal activity of C-17-fengycin B, which also demonstrated good biocompatibility, making it a potential candidate for the development of biocontrol pesticides in the future.