Antifungal, anti‐oomycete and phytotoxic effects of volatile organic compounds from the endophytic fungus Xylaria sp. strain PB 3f3 isolated from Haematoxylon brasiletto

Aims To determine the antifungal, anti‐oomycete and phytotoxic activity; and chemical composition of the volatile organic compounds ( VOC s) produced by endophytic fungus Xylaria sp. PB 3f3 isolated from Haematoxylon brasiletto Karst. Methods and Results Bioactivity and chemical composition of the VOC s from Xylaria sp. PB 3f3 were established by using simple and multiple antagonism bioassays, and gas chromatography/mass spectrometry, respectively. The results showed that Xylaria sp. PB 3f3 inhibited the growth of the oomycetes Pythium aphanidermatum (78·3%), Phytophthora capsici (48·3%), and the fungi Alternaria solani (24·5%) and Fusarium oxysporum (24·2%), in multiple antagonism bioassays. Volatile organic compounds, produced at 20 and 30 days of fungal growth, inhibited root elongation on Amaranthus hypochondriacus (27·6%) and on Solanum lycopersicum (53·2%). Forty VOC s were identified at 10, 20 and 30 days in Xylaria sp. PB 3f3 cultures. The compounds with the highest fibre affinity were: 3‐methyl‐1‐butanol and thujopsene, at 10 days of fungal growth; an unidentified amine and 2‐methyl‐1‐butanol at 20 days; and 2‐methyl‐1‐propanol at 30 days. In the gas phase assay method 2‐methyl‐1‐propanol and 2‐methyl‐1‐butanol showed significant inhibitory effects on root elongation and germination of Am. hypochondriacus and S. lycopersicum . Conclusions Xylaria sp. PB 3f3 and its VOC s showed significant phytotoxic effects on root elongation and germination of Am. hypochondriacus and S. lycopersicum . Significance and Impact of the Study The genus Xylaria produces a great variety of secondary metabolites, but, up date, there are no reports of the identification of bioactive volatile compounds. Thus, Xylaria sp. PB 3f3 and its VOC s are a possible candidate for the biological control of weeds.