Antifungal activity of Burkholderia sensu lato metabolites against coffee phytopathogens: evidence of chemical diversity.

The environmental and health concerns associated with the widespread use of synthetic pesticides have intensified the search for sustainable alternatives to control phytopathogenic fungi. In this context, members of the Burkholderia sensu lato group have been recognized for their ability to produce diverse bioactive metabolites with antifungal properties. In this study, the antifungal activity of 36 rhizosphere-derived strains was evaluated against Hemileia vastatrix, Fusarium solani, Fusarium oxysporum, and Alternaria longissima. Approximately 80% of the strains inhibited the uredospore germination of H. vastatrix, while 37%, 50%, and 45% reduced radial growth of F. solani, F. oxysporum, and A. longissima, respectively. Selected strains (GB99, D335, and D416) produced heat-stable metabolites that retained activity across a wide pH range and showed partial resistance to hydrolytic enzymes. Metabolomic profiling by high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (HPLC-ESI-QTOF-MS), performed on metabolites produced by strain GB99, revealed multiple putative antifungal compounds, including burkholdine, occidiofungin and lagriamide related metabolites. Molecular docking, used as an exploratory approach, suggested potential interactions with multiple fungal protein targets. Overall, these findings highlight the chemical diversity and antifungal potential of Burkholderia sensu lato metabolites as promising candidates for sustainable biocontrol strategies.