The biocontrol potential of endophyte Bacillus velezensis to reduce post-harvest tomato infection caused by Rhizopus microsporus

Abstract

Rhizopus microsporus is a necrotrophic post-harvest pathogen that causes significant economic losses in the agricultural sector. To explore alternatives to conventional management strategies for the mitigation of post-harvest infections, we investigated the potential of two previously identified endophytic Bacillus velezensis strains as biological control agents. Through in vitro and in vivo experiments, we examined the mechanisms of biocontrol displayed by two B. velezensis strains (KV10 and KV15) against three R. microsporus strains (W2-50, W2-51, and W2-58). In vitro assays assessed co-cultivability and the inhibitory effects of B. velezensis against R. microsporus. The results demonstrated strain-specific antifungal activity with a reduction in fungal growth across treatments. Further analysis revealed that volatile organic compounds produced by B. velezensis contributed to its antifungal properties. To evaluate the biocontrol efficacy in vivo, tomato fruits were inoculated with R. microsporus and subsequently treated with B. velezensis. The results support the strain-specific reduction in tomato spoilage, yielding various spoilage rates observed across treatments. Our findings highlight the potential of B. velezensis as a promising biocontrol agent for the management of R. microsporus post-harvest infections in tomatoes. Further research is warranted to optimize the application of B. velezensis as a sustainable and environmentally friendly approach for controlling post-harvest diseases in tomatoes.