Microbial Influence on Plant Volatile Organic Compound Emission and Its Ecological Impact

Abstract

Plant volatile organic compounds (VOCs) are low-molecular-weight, high-vapour-pressure metabolites that mediate a large fraction of the chemical communication occurring above and below ground. plant growth-promoting rhizobacteria (PGPR), arbuscular mycorrhizal fungi (AMF), endophytes and the wider soil microbiome—reshape the composition, quantity and ecological function of plant volatilomes. Across the collated evidence, microbial colonisation rarely leaves the volatilome unchanged. Bacterial inoculants such as Bacillus and Pseudomonas spp. prime the emission of green-leaf volatiles, terpenoids and methyl salicylate through induced systemic resistance (ISR) linked to jasmonic-acid, salicylic-acid and ethylene signalling. AMF symbioses (e.g. Funneliformis mosseae) elevated leaf VOC pools by as much as 85% and increased terpenoid content by roughly half in quantitative meta-analyses, while reductions in soil microbial diversity paradoxically raised total VOC flux but narrowed its chemical richness. The ecological consequences are multi-trophic: microbially reprogrammed blends alter herbivore performance, recruit parasitoids and predators, suppress phytopathogens, structure neighbouring microbial communities and feed back onto atmospheric chemistry through biogenic emissions. Five secondary-data tables summarise emission shifts, functional mechanisms and trophic outcomes. The synthesis argues that the plant volatilome is best understood as a holobiont trait, jointly encoded by host and microbiome, with direct relevance for sustainable pest management, biocontrol and climate-linked emission modelling.