Microbial volatile compounds alter the soil microbial community.

Volatile organic compounds (VOCs) from soil bacteria are likely to have an important role in the interactions among soil microorganisms. However, their effects on the soil microbial community have not been extensively studied. In this study, the effect of bacterial VOCs generated by growing Bacillus amyloliquefaciens NJN-6 on modified MS medium on soil microbial community was evaluated. B. amyloliquefaciens NJN-6 was able to produce 48 volatile compounds as determined by solid-phase microextraction-GC/MS. MiSeq sequencing data showed that bacterial VOCs could alter the composition of both soil bacterial and soil fungal communities and could decrease the alpha-diversity of the soil microbial community. Taxonomic analysis revealed that bacterial VOCs significantly increased the relative abundance of Proteobacteria, Bacteroidetes, and Firmicutes. Moreover, bacterial VOCs significantly increased the relative abundance of Ascomycota. The qPCR data showed that bacterial VOCs of strain NJN-6 decreased the soil fungal biomass and increased the soil bacterial biomass. Further evaluation of the effect of bacterial VOCs on functional genes revealed that VOCs could reduce the copies of nifH, nirS, and a gene encoding nonribosomal peptide synthase, while increasing the copy number of the ammonium-oxidizing bacteria gene. The effect on gene encoding polyketide synthase was insignificant. Results from this study indicated that bacterial VOCs could influence the soil microbial community as well as functional gene abundance.