Unveiling the Antagonistic Mechanism of Pseudomonas aeruginosa Y010 Directs Targeted Genetic Screening for Enhanced Biocontrol Efficacy

Bacterial soft rot, mainly caused by Dickeya and Pectobacterium pathogens, leads to severe economic losses in agriculture. Recently, we isolated a rhizosphere strain Pseudomonas aeruginosa Y010, which is a potential biocontrol agent for bacterial soft rot. However, the underlying antagonistic mechanisms remain unknown. In this study, we explored the antagonistic mechanism of P. aeruginosa Y010 against two important pathogens, P. aroidearum ZL1 and D. fangzhongdai CL3, and found that pyocyanin (PYO) is the key component exhibiting antagonistic activity. Using the green-blue color PYO production as a rapid readout, genome-wide transposon mutagenesis successfully generated a mutant (26330::Tn) with elevated PYO production and biocontrol efficacy. Both Y010 and its genetically modified mutant 26330::Tn exhibited no phytotoxicity to plants, highlighting their biosafety as biocontrol agents. This study elucidates the antagonistic mechanism of Y010 and provides a strategy of rapid genetic modification for biocontrol agents to manage plant diseases.