Nematicidal and Insecticidal Compounds from the Laurel Forest Endophytic Fungus sp.

The search for natural product-based biopesticides from endophytic fungi is an effective tool to find new solutions. In this study, we studied a pre-selected fungal endophyte, isolate YCC4, from the paleoendemism , along with compounds present in the extract and the identification of the insect antifeedant and nematicidal ones. The endophyte YCC4 was identified as sp. by molecular analysis. The insect antifeedant activity was tested by choice bioassays against , and and the in vitro and in vivo mortality was tested against the root-knot nematode . Since the extract was an effective insect antifeedant, a strong nematicidal, and lacked phytotoxicity on tomato plants, a comprehensive chemical study was carried out. Two new metabolites, metguignardic acid () and (-)--guignardone I (), were identified along the known dioxolanones guignardic acid (), ethyl guignardate (), guignardianones A (), C (), D (), and E (), phenguignardic acid methyl ester (), the meroterpenes guignardone A () and B (), guignarenone B () and C (), (-)-guignardone I (), and phyllomeroterpenoid B (). Among these compounds, and were effective antifeedants against and , while was only active on the aphid . The nematicidal compounds were , , and . This is the first report on the insect antifeedant or nematicidal effects of these dioxolanone-type compounds. Since the insect antifeedant and nematicidal activity of the sp. extract depend on the presence of dioxolanone components, future fermentation optimizations are needed to promote the biosynthesis of these compounds instead of meroterpenes.