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.

本研究探究了细菌联合体在防治辣椒疫霉（Phytophthora capsici）以及促进辣椒（Capsicum annuum L.）生长方面的应用。该联合体包含5株从健康辣椒根际分离得到的细菌菌株，分别为芽孢杆菌属（Bacillus sp.）T3、安徽黄杆菌（Flavobacterium anhuiense）T4、坚硬细胞杆菌（Cytobacillus firmus）T8、玫瑰色链霉菌（Streptomyces roseicoloratus）T14以及弗雷德里克堡假单胞菌（Pseudomonas frederiksbergensis）A6。对这些菌株的生化特性表征结果显示，它们具备溶解磷酸盐、产生过氧化氢酶与吲哚-3-乙酸（IAA）以及合成铁载体的能力，表明其作为植物促生根际细菌（PGPR）的应用潜力。体外抗真菌试验表明，该联合体对辣椒疫霉（P. capsici）——一种引发辣椒根腐与茎腐病的主要病原菌——具有较强的拮抗活性。为验证上述试验结果，本研究开展了受控生长室试验，设置仅接种病原菌的对照组与接种病原菌+细菌联合体的处理组进行对比。培养60天后，处理组植株的生长参数得到显著改善，病害得到有效抑制；而对照组植株则出现病害症状，包括叶片产生淡黄色至黑色病斑。