Comprehensive volatile organic compounds profiling of Bacillus species with biocontrol properties by head space solid phase microextraction with gas chromatography-mass spectrometry
The eight Bacillus strains, used as biocontrol agents with proven antagonistic effect against plant pathogens, produced antifungal volatile organic compounds (VOCs). Bioassay in sealed dishes revealed that the VOCs from each Bacillus strain significantly inhibited the mycelial growth (56–82%) of Fusarium solani. The effective antifungal VOCs were extracted using headspace solid phase microextraction and further identified by gas chromatography-mass spectrometry technique. The detected volatile compounds could be chemically grouped into ketones, alcohols, aldehydes, pyrazines, acids, esters, pyridines and benzene compounds. The ketones and alcohols were predominant in the VOCs from eight Bacillus strains whereas the ketones, including 3-methyl-2-pentanone, 2-heptanone, 2-octanone, 2-decanone, 5-methyl-2-hexanone, 2-nonanone, 2-dodecanone, 2-undecanone, 5-methyl-2-heptanoneand2-pentanone, were the most common and principal components in all strains. Present results showed that the eight Bacillus strains are rich resources of bioactive volatiles, which may play an important role in the inhibition on F. solani. Studies are under the way to determine effects of those compounds against plant pathogens and to find the possible action mechanisms.