Study on the Biocontrol Potential of Antifungal Peptides Produced by Bacillus velezensis against Fusarium solani That Infects the Passion Fruit Passiflora edulis

A bacterium identified as Bacillus velezensis with a growth inhibitory effect against Fusarium solani, a pathogen that caused basal stem rot in the passion fruit Passiflora edulis, was isolated in this study. From the fermentation broth of B. velezensis, a type of antifungal peptide (named BVAP) with a molecular weight of ca. 1.5 kDa was purified and found to be fengycin. BVAP suppressed mycelial growth in F. solani with an IC50 of 5.58 mu g/mL, which was superior to those of the chemical fungicides thiram (41.24 mu g/mL) and hymexazol (343.31 mu g/mL). The antifungal activity remained stable after exposure to 50-100 degrees C or following incubation with solutions at pH 1-3. Further research revealed that BVAP increased the permeability of the F. solani mycelial membrane, brought about swelling at the tips of hyphae, and elicited abnormal accumulation of nucleic acids and chitin at the sites of swelling. These findings indicate that BVAP possessed a remarkable biocontrol potential toward F. solani.

Automated summary

The study isolated a bacterium identified as Bacillus velezensis, which produced an antifungal peptide (BVAP) with inhibitory effects against Fusarium solani, the pathogen causing basal stem rot in passion fruit. BVAP showed superior antifungal activity compared to chemical fungicides, potentially by increasing mycelial membrane permeability and inducing abnormal cellular accumulation to achieve biocontrol against the pathogen.