New Analogs Produced by the Co-Culture of the Endophyte Xylaria sp. and Phytophthora

Species within the oomycete Phytophthora genus are very aggressive pathogens capable of producing enormous losses on host plants, including Rhododendron spp. Over 600 endophytic fungi were isolated from healthy leaves of Rhododendron from which 118 showed some inhibitory effect toward Phytophthora spp.; among those isolates a Xylaria sp. was selected for further studies. Biodirected purification of the Xylaria culture filtrate allowed us to isolate and identify a Phytophthora inhibitor. Co-cultures between the endophyte fungus Xylaria and Phytophthora showed increasing production of the active metabolite, as well as new metabolites with unusual substitution patterns..