Volatile organic compounds from Bacillus spp. reduce egg hatching, motility, infectivity and reproduction of Meloidogyne incognita

Abstract Volatile organic compounds (VOCs) produced by microorganisms have several roles, such as communication and antimicrobial defence. Soil and endophytic bacteria employ VOCs in their interactions with plants, other bacteria, fungi and nematodes. In this study, the VOCs produced by 36 endophytic bacterial strains from pepper and tomato plants were tested for their antagonism to the nematode Meloidogyne incognita. The VOCs produced by most bacterial strains (94%) caused a strong decrease in motility, while 69% of the strains caused high mortality rates in second-stage juveniles (J2s) of M. incognita. Among the strains that simultaneously caused a strong decrease in motility and high mortality, Bacillus pumilus strains 51 and 52 and B. sphaericus strain 43 were selected for further studies. These three strains produced VOCs that decreased egg hatching, infectivity and reproduction on tomato plants. Gas chromatography revealed a diverse VOC profile in the three studied strains, with 36% of compounds not previously reported in bacteria. Only decan-2-one and 2-ethylhexanol out of the eight VOCs produced by the bacterial strains significantly reduced motility (3%) and increased mortality (82%) of M. incognita J2s when tested in their purified form. These findings highlight both the potential of VOCs as templates for new nematicides and the bacterial strains as biocontrol agents against M. incognita.