Endophytic fungi from two isolated <i>Bethencourtia palmensis</i> populations <i>:</i> metabolomic and bioactivity fingerprinting

BACKGROUND: Bethencourtia palmensis (Nees) Choisy is an endemic plant of the Canary Islands, with different populations on La Palma and Tenerife, that contains biopesticidal compounds and whose endophytic fungi have also shown potential for biopesticide production. This study explores the metabolic and biopesticide potential of endophytic culturable fungi isolated from two island populations of Bethencourtia palmensis [Tenerife (T) and La Palma (P)]. RESULTS: The two plant populations showed distinct chemical profiles: 11β-acetoxy-5α-(angeloyloxy)silphinen-3-one and tetratriacontane were major components in T, while 5α-senecioyloxy-silphinen-3-one, tetratriacontane, and jacaranone were predominant in P. From potato dextrose agar (PDA) medium, 21 and 16 fungal isolates were obtained from T and P, respectively. Ethyl acetate extracts were tested against Myzus persicae, Meloidogyne javanica, Botrytis cinerea, and Fusarium verticillioides. Three isolates from T (14%), belonging to Aspergillus and Penicillium, showed bioactivity. In contrast, 13 isolates from the P population (81%) were bioactive and belonged to Alternaria, Aureobasidium, Aspergillus, Penicillium, and Stemphylium. Additional isolation from P using YES medium (2% yeast extract, 15% sucrose, 1.5% agar) yielded 31 new isolates, 20 of which (65%) were bioactive, including genera not recovered on PDA. Gas chromatography-mass spectrometry-based metabolite fingerprinting revealed distinctive patterns associated with specific genera. CONCLUSION: The findings highlight significant differences in the plant chemistry and bioactive endophytes between two island populations of B. palmensis. Furthermore, these strains are a promising source of bioactive compounds. The diverse range of bioactivities observed suggests high potential for the discovery of novel biopesticides with applications in sustainable agriculture. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.