Integrated microbiome and metabolome profiling reveals rhizosphere responses to chitosan application in tobacco

ABSTRACT: Chitosan is widely investigated as a plant biostimulant, but its effects on the rhizosphere microbiome and metabolome under field conditions remain poorly understood. Here, we evaluated the response of the tobacco (Nicotiana tabacum L.) rhizosphere to chitosan root-drench treatment by integrating bacterial 16S rRNA and fungal ITS amplicon sequencing with untargeted LC–MS/MS metabolomics. Chitosan had limited effects on the overall structure of rhizosphere bacterial and fungal communities, as indicated by Bray–Curtis-based community analyses, but was associated with selective changes in specific microbial taxa. Several bacterial biomarkers differed between treatments, while fungal community richness and predicted trophic profiles also showed treatment-associated changes. In contrast to the relatively modest changes in overall microbial community structure, rhizosphere metabolite profiles showed clear treatment-associated differences. Differential metabolites were mainly related to carbon metabolism, amino acid metabolism, phenylpropanoid biosynthesis, vitamin metabolism, alkaloid biosynthesis, and other secondary metabolic pathways. Functional prediction further suggested changes in the metabolic and ecological potential of bacterial and fungal communities following chitosan application. Correlation analysis identified associations between differential metabolites and specific bacterial and fungal taxa, providing candidate links between microbial community composition and rhizosphere chemical variation. Together, our results suggest that chitosan acts primarily as a selective modulator of the rhizosphere microbiome and chemical environment rather than as a broad-spectrum driver of microbial community restructuring. The integrated microbiome–metabolome framework used here provides a basis for understanding how chitosan application may influence plant–soil–microbe interactions under field conditions.

INSTRUMENT(S): Liquid Chromatography MS - negative - reverse-phase, Liquid Chromatography MS - positive - reverse-phase

PROVIDER: MTBLS15706 | MetaboLights | 2026-09-17

REPOSITORIES: MetaboLights