Evaluation of Pseudomonas chlororaphis JK77 as a biocontrol agent for Fusarium graminearum in maize stalk rot management

Maize stalk rot, predominantly caused by Fusarium graminearum, poses a serious threat to maize production in China. Biological control represents a viable and sustainable strategy for its suppression.In vitro and pot experiments confirmed that Pseudomonas chlororaphis isolate JK77 could effectively control the occurrence of maize stalk rot caused by F. graminearum, with 1 × 10⁹ CFU (Colony-Forming Unit) mL⁻¹ achieving 73.5% inhibition. Identified by MALDI-TOF MS, the antifungal activity was attributed to a synergistic blend of C19 fengycin A, viscosin, and pseudophomin A that collectively compromised membrane integrity, caused hyphal deformation, protoplasm aggregation, and swelling, and strongly inhibited key fungal developmental stages. Our findings highlight the utility of P.chlororaphis JK77 as a promising biocontrol agent against maize stalk rot, elucidate its mechanism underlying the inhibition of Fusarium graminearum growth, aiding biocontrol agent development.