Role of Volatiles from the Endophytic Fungus PSU-P1 in Biocontrol Potential and in Promoting the Plant Growth of .

Fungal volatile organic compounds (VOCs) emitted by species interact with a plant host and display multifaceted mechanisms. In this study, we investigated the antifungal activity of VOCs emitted by PSU-P1 against fungal pathogens, as well as the ability of VOCs to activate defense responses and to promote plant growth in . The strain's VOCs had remarkable antifungal activity against fungal pathogens, with an inhibition range of 15.92-84.95% in a volatile antifungal bioassay. The VOCs of PSU-P1 promoted the plant growth of , thereby increasing the fresh weight, root length, and chlorophyll content in the VOC-treated relative to those of the control. High expression levels of the chitinase () and β-1,3-glucanase () genes were found in the VOC-treated by quantitative reverse transcription polymerase chain reaction (RT-PCR). The VOC-treated had higher defense-related enzyme (peroxidase ()) and cell wall-degrading enzyme (chitinase and β-1,3-glucanase) activity than in the control. The headspace VOCs produced by PSU-P1, trapped with solid phase microextraction, and tentatively identified by gas chromatography-mass spectrometry, included 2-methyl-1-butanol, 2-pentylfuran, acetic acid, and 6-pentyl-2H-pyran-2-one (6-PP). The results suggest that PSU-P1 emits VOCs responsible for antifungal activity, for promoting plant growth, and for inducing defense responses in .