The selective anti-fungal metabolites from Irpex lacteus and applications in the chemical interaction of Gastrodia elata, Armillaria sp., and endophytes

Abstract

The investigation of the metabolites from endophyte Irpex lacteus cultured in host “tian ma” (Gastrodia elata) revealed five new tremulane sesquiterpenes (1–5), and a new tetrahydrofuran derivative (6). Compound 1 was the first tremulane glucoside, and 6 possessed a rare tetrahydropyran-tetrahydrofuran scaffold. Main metabolite (2,3-dihydroxydodacane-4,7-dione, 14) from I. lacteus showed significant selectivity for antifungal activity against phytopathogen and endophytes associated with G. elata rather than against Armillaria sp. providing nutrition for the host G. elata. 14 accounted for 27.4% of isolated compounds from G. elata medium, and 69.3% by co-culturing with Armillaria sp. So the I. lacteus tended to promote the growth of Armillaria sp. in co-culture by producing 2,3-dihydroxydodacane-4,7-dione (14) to selective inhibit the phytopathogen and endophyte existed in host G. elata for the benefit of G. elata-Armillaria symbiosis. And the results were in accord with the real environment of G. elata depending on the nutrition of Armillaria. Some metabolites had anti-fungal activities against phytopathogens of G. elata with MICs ≤8 μg/mL.