Exploring the Biocontrol Potential of Pochonia chlamydosporia : Antifungal and Nematicidal Activities of Culture Filtrates and Secondary Metabolites

This study investigated the biocontrol potential of culture filtrates and secondary metabolites (SMs) from the nematophagous fungus Pochonia chlamydosporia. The fungus exhibited antifungal activity against pathogens such as Pythium myriotylum, Macrophomina sp., Colletotrichum sp., Phytophthora sp., Fusarium sp., and Exerohilum rostratum. The highest percentage inhibition of radial growth values was observed with P. myriotylum (81.42%) and Phytophthora sp. (82.71%), while Macrophomina sp. showed the lowest inhibition (40%). The study also aimed to identify the SMs responsible for the biocontrol activity of P. chlamydosporia. Secondary metabolites were extracted using ethyl acetate, and their activity profiles were assessed via thin-layer chromatography. The ethyl acetate extracts fully inhibited the mycelial growth of P. myriotylum (99.54%) and Phytophthora sp. (99.99%). Moreover, the extract demonstrated significant nematicidal activity against the plant-parasitic nematode (PPN) Radopholus similis, with the crude extract showing the highest efficacy among various concentrations tested. High-resolution ultra-performance liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry analysis of the extract revealed a diverse array of bioactive compounds, including antifungal, antibacterial, antiviral, antitumor, cytotoxic, antimalarial, antitrypanosomal, and nematicidal agents. An in-silico screening approach was employed to identify potential lead compounds for nematicidal activity, targeting glutathione S-transferases and venom allergen-like proteins. The results highlighted three compounds, bisevertinol, enniatin I, and enniatin H, that exhibited strong binding affinities to multiple pharmacological targets, suggesting their potential as lead candidates for developing nematicidal agents against PPNs.