Studies of microbial diversity on Pepper's rhizosphere under disease pressure

This study investigates the application of a bacterial consortium for the biological control of Phytophthora capsici and the growth promotion of pepper (Capsicum annuum L.). The consortium comprised five bacterial strains isolated from the rhizosphere of healthy pepper plants: Bacillus sp. T3, Flavobacterium anhuiense T4, Cytobacillus firmus T8, Streptomyces roseicoloratus T14, and Pseudomonas frederiksbergensis A6. Biochemical characterization of these strains revealed their ability to solubilize phosphate, produce catalase and indole-3-acetic acid (IAA), and synthesize siderophores, suggesting their potential as plant growth-promoting rhizobacteria (PGPR).In vitro antifungal assays demonstrated strong antagonistic activity of the consortium against P. capsici, a major pathogen causing root and crown rot in peppers. To validate these findings, a controlled growth chamber experiment was conducted, comparing a control group (pathogen only) with a treated group (pathogen + bacterial consortium). After 60 days, the treated plants exhibited improved growth parameters and significant disease suppression, whereas the control plants showed disease symptoms, including yellowish and black leaf spots.