An endophytic Gliocladium sp. of Eucryphia cordifolia producing selective volatile antimicrobial compounds

Abstract

An endophytic isolate of Gliocladium sp. was obtained from the Patagonian Eucryphiacean tree— Eucryphia cordifolia, known locally as “ulmo”. The fungus was identified on the basis of its morphology and aspects of its molecular biology. This fungus produces a mixture of volatile organic compounds (VOC's) lethal to such plant pathogenic fungi as Pythium ultimum and Verticillum dahliae, while other pathogens were only inhibited by its volatiles. Some of the same volatile bioactive compounds exuded by Gliocladium sp. such as 1-butanol, 3-methyl-, phenylethyl alcohol and acetic acid, 2-phenylethyl ester, as well as various propanoic acid esters, are also produced by Muscodor albus, a well known volatile antimicrobial producer. In fact, M. albus was used as a selection tool to effectively isolate Gliocladium sp. since it is resistant to VOC's produced by M. albus. However, the primary volatile compound produced by Gliocladium sp. is 1,3,5,7-cyclooctatetraene or [8]annulene, which by itself, was an effective inhibitor of fungal growth. The authenticated VOC's of Gliocladium sp. were inhibitory to all, and lethal to some test fungi in a manner that nearly mimicked the gases of Gliocladium sp. itself. This report shows that the production of selective volatile antibiotics by endophytic fungi is not exclusively confined to the Muscodor spp.