The endophytic fungus Aspergillus sp. SPH2 was isolated from the stems of the endemic plant Bethencourtia palmensis and its extracts were found to have strong fungicidal effects against Botrytis cinerea and ixodicidal effects against Hyalomma lusitanicum at different fermentation times. In this study, the fungus was grown using three different culture media and two methodologies, Microparticulate Enhancement Cultivation (MPEC) and Semi-Solid Fermentation (SSF), to increase the production of secondary metabolites in submerged fermentation. The addition of an inert support to the culture medium (SSF) resulted in a significant increase in extract production. However, when talcum powder was added to different culture media, unexpected results were observed, with a decrease in the production of the biocompounds of interest. Metabolomic analyses showed that the production of aspergillic, neoaspergillic, and neohydroxyaspergillic acids peaked in the first few days of fermentation, with notable differences observed among the methodologies and culture media. Mellein production was particularly affected by the addition of an inert support to the culture medium. These results highlight the importance of surface properties and morphology of spores and mycelia during fermentation by this fungal species.

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 Persea indica, along with compounds present in the extract and the identification of the insect antifeedant and nematicidal ones. The endophyte YCC4 was identified as Phyllosticta capitalensis by molecular analysis. The insect antifeedant activity was tested by choice bioassays against Spodoptera littoralis, Myzus persicae and Rhopalosiphum padi and the in vitro and in vivo mortality was tested against the root-knot nematode Meloiydogyne javanica. Since the extract resulted an effective insect antifeedant, a strong nematicidal and lacked phytotoxicity on tomato plants, a comprehensive phytochemical study was carried out. The chemical study resulted in the identification of two new metabolites, metguignardic acid (4) and (-)-epi-guignardone I (14), along the known dioxolanones guignardic acid (1), ethyl guignardate (3), guignardianones A (5), C (2), D (7) and E (6), phenguignardic acid methyl ester (8), and the meroterpenes guignardone A (9) and B (10) and guignarenone C (12), (-)-guignardone I (13) and the phyllomeroterpenoid B (15). Among these compounds, 1 and 4 were effective antifeedants against both insect species, while 2 was only active on the aphid M. persicae. The nematicidal compounds were 4, 7 and 8. 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 P. capitalensis extract depends on the presence of dioxolanone components, future fermentation optimizations are needed to promote the biosynthesis of these compounds instead of the meroterpenes.