Antagonistic activity of Bacillus subtilis CW14 and its β-glucanase against Aspergillus ochraceus

Bacillus subtilis CW14 and β-glucanase produced were used to inhibit Aspergillus ochraceus, for detecting its antifungal activity and exploring the mechanism. Results showed that CW14 supernatants with molecular weights (Mw) >10 kDa had the best antifungal activity, increased the contents of chitin and active oxygen (ROS), inhibited mycelial growth and spores germination of A. ochraceus, and increased the production of OTA. Besides, it might activate the CWI signaling pathway at the molecular level, and affect its secondary metabolism of A. ochraceus. After LC-MS/MS analysis, the proteins with the antifungal effect of Mw > 10 kDa might be a series of glycoside hydrolase or ribonuclease which inhibit cell wall growth. The antifungal protein β-glucanase in the CW14 genome was found and was heterogeneously expressed in Pichia pastoris. Its stability and antifungal activity were evaluated, and the antifungal rate reached 97.1%. •The supernatant (Mw > 10 kDa) of B. subtilis CW14 had the highest antifungal activity.•Antifungal substances could inhibit mycelial extension and spore germination.•The mechanism might be related to the activation of the CWI pathway on A. ochraceus.•The recombinant β-glucanase showed significant protection on Soybean against fungi.•OTA might exist as a self-defense substance of fungi against a sublethal state.