Compostos orgânicos voláteis (COVs) emitidos por Bacillus sp. no controle biológico de fitopatógenos

Abstract

Bacteria of the genus Bacillus play an important role as biocontrol agents due to the production of volatile organic compounds (VOCs), commonly reported as mycelial growth inhibitors of different fungal pathogens. The objective of the present work was the structural identification and evaluation of the antifungal potential of volatile organic compounds (VOCs) emitted by a bacterial strain of Bacillus sp. (LPPC265), isolated from the banana rhizosphere, against the pathogens Fusarium oxysporum f. sp. cubense (LPPC130) and Colletotrichum sp. (LPPC388). The antagonism experiment was performed by the plate pairing method, containing the antagonist Bacillus sp. (LPPC265) and a pathogen (LPPC130 or LPPC388). The results revealed that the VOCs of Bacillus sp. (LPPC265) inhibited the fungi LPPC130 and LPPC388 by 44.8% and 55.8%, after 6 and 4 days of incubation, respectively. The VOCs were obtained by headspace mode solid-phase microextraction (HS-SPME), and the analysis was performed using a gas chromatograph coupled to a mass spectrometer (GC-MS). The use of the NIST data library, combined with a comparative analysis of Kovats indices and mass spectra, allowed the characterization of eleven volatile compounds emitted by the bacterium, of which we highlight 2-methyl-1,3-butadiene, 3-methyl-1-butanol, methylisobutylketone, butanoic acid, 3-methylbutanoic acid and 2-methylbutanoic acid, which are already reported in the literature as important substances in the biocontrol of phytopathogens.