Isolation and characterization of new antagonistic bacteria P10-7 and evaluation of its biocontrol potential against tomato gray moldIsolation, biocontrol and whole-genome sequence analysis of new antagonistic bacteria on Botrytis cinerea

Denghui ChenDandan YueGuanjie LiZongyuan ZhangLiuzhu ZhouHongguang XuDehai LiuXueyan Wang^*

• HE NAN ACADEMY OF SCIENCE, Zheng Zhou, China

Gray mold, caused by Botrytis cinerea, is one of the most destructive fungal diseases, causing significant losses in cash crops, especially tomatoes, worldwide. To address this challenge, we isolated and characterized a novel bacterial strain, P10-7, from tomato rhizosphere soil. Identification was performed using morphological, physiological, biochemical, and whole-genome sequencing analyses. The biocontrol potential of P10-7 was assessed through in vitro antagonism assays, analysis of secondary metabolites and lytic enzymes, and greenhouse pot experiments.In this study, we isolated a bacterium called P10-7, identified and analyzed it through morphology, physiology, biochemistry, and whole genome sequencing; its antagonistic properties, secondary metabolites, bioprophylaxis, and biocontrol capabilities were evaluated using plate antagonism, biochemical assays, and pot experiments. Results showed that P10-7 was a strain of Bacillus amyloliquefaciens, with a total genome size of 3929792 bp, including 12 biosynthetic gene clusters. The antagonism test demonstrated broad-spectrum antifungal activity against seven fungal pathogens, including gray mold, with inhibition rates of 92.09% for mycelial growth and 98.03% for spore germination. Biochemical tests confirmed the strain's ability to produce amylase, protease, pectinase, and siderophores. Further experiments showed that the strain could produce secondary metabolites such as amylase, protease, pectinase, and glycosides. Furthermore, application of a P10-7 cell suspension at 1×10⁷ CFU/mL significantly promoted tomato seed germination and enhanced seedling growth (height, root length, fresh and dry weight). Critically, this treatment also markedly reduced disease incidence and effectively controlled tomato gray mold in greenhouse trials. Bioprevention trials indicated that a spore solution at 1×10⁷ cfu/mL could promote tomato seed germination, increase seedling height, root length, dry weight, and fresh weight, while effectively reducing disease incidence and controlling gray mold in tomatoes. Collectively, oOur study findings demonstrate suggests that Bacillus amyloliquefaciens P10-7 exhibits has significant potential as an effective biocontrol agent against Botrytis cinerea.