Coating Seeds with Paenibacillus polymyxa ZF129 Microcapsule Suspension Enhanced Control Effect on Fusarium Root Rot and Promoted Seedling Growth in Cucumber

In this study, a Paenibacillus polymyxa ZF129 microcapsule suspension (CS-ZF129) was prepared. P. polymyxa ZF129 was microencapsulated by gum arabic via the spray-drying method. Coating seeds with the CS-ZF129 not only increased the control efficacy against cucumber root rot to 46.30 ± 0.02%, but also promoted the growth of the cucumber roots and other aspects, effectively improving the colonization ability of polymyxa ZF129 in the cucumber root system, which was analyzed to clarify the biological control mechanism of the cucumber Fusarium root rot disease through the enzyme activity. This study provides an efficient means based on seed coating for the biological control of cucumber Fusarium root rot. Fusarium root rot, a destructive soil-borne fungal disease, necessitates eco-friendly biocontrol strategies. This study developed a microbial seed-coating approach using the antagonistic strain Paenibacillus polymyxa ZF129, formulated into a microencapsulated powder (10 8 CFU/g) and a suspension (CS-ZF129). CS-ZF129 application enhanced cucumber resistance, achieving 46.30 ± 0.02% disease suppression while promoting root growth. The maximum increase in the fresh weight of the root in the promotion of rectangular growth was 47.16%. The colonization dynamics of ZF129 in the rhizosphere were systematically tracked, revealing its antagonistic correlation with Fusarium proliferation. An enzymatic activity analysis further uncovered the underlying regulatory mechanisms, demonstrating induced defense responses through pathogenesis-related protein activation. These findings highlight ZF129’s dual functionality as a biocontrol agent and a plant growth promoter, offering a sustainable strategy against soil-borne pathogens.