Abstract

The increasing demand for sustainable crop protection strategies has intensified interest in plant-beneficial bacteria as alternatives to synthetic agrochemicals. In this study, the soil-derived bacterium Pseudomonas putida V01 was isolated and characterized for its antifungal and plant growth-promoting potential through an integrated approach combining biological assays, untargeted metabolomics, and in vivo plant experiments. Cell-free culture filtrates exhibited strong antifungal activity against major phytopathogenic fungi, completely inhibiting the growth of Sclerotium rolfsii and significantly reducing mycelial development of Alternaria alternata and Fusarium proliferatum by 40% and 20%, respectively. Volatile organic compounds (VOCs) selectively inhibited Botrytis cinerea and A. alternata by 28% and 10%, respectively, and affected sporulation of F. proliferatum. Metabolomic profiling through LC-qTOF-MS and GC-MS analyses revealed a chemically diverse metabolome, including putatively annotated diketopiperazines, cyclic peptides, phenolic compounds, and fatty acids. VOC profiling indicated ketones and alcohols as the predominant volatile classes, with 2-undecanone and 2-undecanol among the most abundant compounds detected. In vivo assays on wheat seedlings showed significant increases in shoot growth, biomass accumulation, and chlorophyll content compared with untreated controls. These findings indicate that P. putida V01 combines complementary antifungal and plant growth-promoting activities associated with a diverse repertoire of diffusible and volatile metabolites. The integrated biological and metabolomic characterization highlights its potential as a multifunctional microbial inoculant for sustainable crop production and disease management.

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