Antagonism of volatile organic compounds of the Bacillus sp. against Fusarium kalimantanense.

Fusarium kalimantanense is a genetic lineage of Fusarium oxysporum f. sp. cubense (Foc) and belongs to the Fusarium oxysporum species complex (FOSC). This pathogen is a causative agent of Panama disease, an infection that has caused damage to the banana crop worldwide. Bacillus sp. (LPPC170) showed preliminary antagonist activity against F. kalimantanense (LPPC130) in vitro tests from the cultivation of axenic culture and co-culture with inhibition of mycelial growth of phytopathogen of 41.23%. According to these findings, volatile organic compounds (VOCs) emitted from Bacillus sp. were obtained by solid-phase microextraction and identified by gas chromatography coupled with a mass spectrometer (GC-MS). The multivariate data analysis tool (PLS-DA and Heatmap) identified short-chain organic acids as the main antagonistic VOCs responsible for inhibiting the mycelial growth of LPPC130. Acetic acid, propanoic acid, butanoic acid, valeric acid, and isovaleric acid exhibited a strong inhibitory effect on the mycelial growth of LPPC130, with inhibition of 20.68%, 33.30%, 26.87%, 43.71%, and 53.10%, respectively. Scanning electron microscopy revealed that VOCs caused damage to the vegetative and reproductive structures of the fungus. These results suggest Bacillus LPPC170 as an excellent biocontrol tool against the phytopathogen causative agents of Panama disease.