Existence of Muscodor vitigenus, M-equiseti and M-heveae sp nov in leaves of the rubber tree (Hevea brasiliensis Mull.Arg.), and their biocontrol potential

We isolated volatile metabolite-producing endophytic fungi from the leaves of the rubber tree (Hevea brasiliensis Mull.Arg.) and studied their antimicrobial competence. A total of three isolates was obtained, and their phenotypic and phylogenetic relationship with the genus Muscodor in the family Xylariaceae was studied. All isolates could produce volatile metabolites with apparent antimicrobial activity against diverse test microbes (bacteria, yeast and filamentous fungi). An isolate, RTM5IV3, with < 86 % similarity with the partial ITS-5.8S rDNA gene as compared to other species of the genus Muscodor, was proposed as a novel species with the name Muscodor heveae sp. nov. Its bioactive volatile metabolites included 3-methylbutan-1-ol as a major component, followed by 3-methylbutyl acetate and azulene derivatives. The volatile organic compounds (VOCs) produced by the Muscodor isolates have the potential for biological control of bacteria, yeast and filamentous fungi. Furthermore, the VOCs of M. heveae were active against the pathogenic fungi Phellinus noxius and Rigidoporus microporus that cause root disease in the rubber tree. We concluded that rubber trees could be an alternative source for discovery of fungi that produce volatile metabolites, and the genus Muscodor could be found abundantly in this habitat.