Pepper Bacterial Spot Control by Bacillus velezensis: Bioprocess Solution

Area of Science:

• Plant Pathology
• Microbial Biocontrol
• Food Microbiology

Background:

• Pepper bacterial spot, caused by Xanthomonas euvesicatoria, poses significant economic threats to pepper production.
• Biocontrol agents offer a sustainable alternative to chemical treatments for plant diseases.
• Bacillus velezensis, a bacterium found in food products, shows potential for agricultural applications.

Purpose of the Study:

• To evaluate Bacillus velezensis IP22, isolated from cheese, as a biocontrol agent against pepper bacterial spot.
• To optimize the cultivation medium for maximizing antimicrobial activity against Xanthomonas euvesicatoria.
• To assess the efficacy of B. velezensis IP22 in planta and identify its antimicrobial metabolites.

Main Methods:

• Optimization of Bacillus velezensis IP22 culture medium for enhanced antimicrobial activity.
• Laboratory-scale bioreactor validation of the optimized medium.
• In planta testing on pepper plants to evaluate disease suppression.
• High-pressure liquid chromatography-mass spectrometry (HPLC-MS) for metabolite analysis.

Main Results:

• Optimized medium significantly enhanced B. velezensis IP22's antimicrobial activity against X. euvesicatoria.
• In planta tests demonstrated substantial suppression of bacterial spot symptoms on pepper plants.
• Reduced disease spread to healthy, uninoculated pepper leaves was observed.
• HPLC-MS analysis identified lipopeptides similar to fengycin and locillomycin families.

Conclusions:

• Bacillus velezensis IP22 is a promising biocontrol agent for pepper bacterial spot.
• The developed bioprocess offers a scalable strategy for producing this food-grade biocontrol agent.
• This approach provides a sustainable solution for plant protection in agriculture.