Pseudomonas protegens as a biocontrol agent against phytopathogenic fungi - mini review.

Pseudomonas protegens, a member of the P. fluorescens complex, is an important biocontrol agent with high potential in sustainable agriculture. It produces diverse secondary metabolites, including 2,4-diacetylphloroglucinol (DAPG), pyoluteorin (PLT), orfamides, and protegenins, as well as hydrolytic enzymes such as chitinases, which contribute to antifungal activity, fungal cell wall degradation, and induction of systemic resistance (ISR) in plants. Despite these insights, gaps remain in understanding the regulation of metabolite biosynthesis, variability of ISR across crops, and the field efficacy of P. protegens. Future research should employ omics approaches (metagenomics, transcriptomics) to optimize biocontrol strategies, explore natural inducers of metabolite production, and evaluate colonization efficiency under field conditions. This review synthesizes current knowledge on P. protegens, highlighting its importance, mechanisms of action, existing knowledge gaps, and directions for future research.