Competitive phenotype and metabolite repertoire of the endophytic Diaporthe sp. PBS30-7

Endophytic fungi represent potential sources of antifungal agents, but the phenotypic and chemical basis of their interactions with competing fungi remains incompletely understood. Here, physiological characterization, time-resolved confrontation assays, cell-free culture-filtrate testing, untargeted chemical profiling, and molecular docking were integrated to characterize the competitive phenotype of the endophytic fungus Diaporthe sp. PBS30-7, isolated from the medicinal plant Pereskia bleo (Kunth) DC., and to prioritize candidate metabolites for subsequent investigation. Diaporthe sp. PBS30-7 exhibited condition-dependent growth and a temporally asymmetric competitive phenotype against two Penicillium species, characterized by sustained colony expansion, progressive restriction of target-fungal growth, and pronounced hyphal abnormalities. Cell-free culture filtrates retained antifungal activity against both target fungi, supporting a contribution of extracellular chemical factors to the overall antagonistic phenotype. Feature-based molecular networking of a culture-associated agar-mycelium extract resolved a chemically diverse repertoire that included putatively annotated beauvericin-type cyclodepsipeptides, diketopiperazines, and unresolved molecular families. Molecular docking further prioritized this candidate chemical space, with beauvericin derivatives displaying particularly favorable target-dependent docking profiles toward CYP51, Fks1, and the ABC transporter, whereas cyclo(L-Tyr-L-Tyr) emerged as a notable diketopiperazine candidate. Together, these findings prioritize candidate metabolites potentially associated with the competitive phenotype of Diaporthe sp. PBS30-7 and provide a foundation for future mechanistic studies of endophytic fungal antagonism.