Abstract
Background
Bacterial strains in the rhizosphere may secrete an array of volatile organic compounds (VOCs), many of which are vital for inter- and intra-kingdom signaling, modulating microbe-microbe and microbe-plant interactions. In this study, we tested the plant growth promoting effect of VOCs emitted by Bacillus sp. NYG5 on several plants, focusing on VOC-induced changes in plant metabolic pathways, soil chemical properties and rhizo-microbiome.
Results
NYG5 emitted VOCs were found to promote growth of Arabidopsis thaliana, Nicotiana tabacum and Cucumis sativus, while also altering the community composition of the rhizosphere microbiome. Furthermore, fluorescent spectral analysis of the soil showed a significant decrease in concentration of humic substances following exposure to NYG5-emitted VOCs. Utilizing SPME-GC-MS analysis, several novel VOCs were identified, some of which were shown to promote plant growth. Transcriptomic analysis of N. tabacum plants exposed to NYG5-emitted VOCs revealed the induction of several plant growth related pathways such as phenylpropanoid biosynthesis, metabolism of sugars, and signal transduction of plant hormones.
Conclusions
Exposure to NYG5-emitted VOCs significantly impacted several plant growth related pathways, increasing plant biomass. Additionally, these VOCs altered the community composition of the rhizosphere microbiome, and decreased the concentration of humic substances in the soil. These findings may suggest that bacterial VOCs significantly impact plant growth via various mechanisms.