Interactions between soil properties, agricultural management and cultivar type drive structural and functional adaptations of the wheat rhizosphere microbiome to drought

Summary

This field study demonstrates that rhizosphere bacterial communities undergo coordinated structural and functional shifts in response to drought, with these adaptations shaped interactively by soil type, agricultural management practice, and wheat cultivar selection. Under drought, Gram-positive bacteria increased in relative abundance, with differential effects on diversity between soil types; notably, enzyme activity and carbon-degradation genes were elevated in the rhizosphere of drought-demanding cultivars managed under organic systems, suggesting potential for microbial-mediated drought mitigation. The findings highlight that unlocking the protective potential of rhizosphere microbiota requires understanding their multi-factor ecological drivers.

Regional applicability

The study used European soil types (German Chernozem and Luvisol) and winter wheat under temperate conditions, making findings potentially applicable to United Kingdom arable systems, particularly for loamy and sandy soils under both conventional and organic management. Transferability to UK conditions is plausible given similar climates and soil types, though local soil microbial communities and cultivar-by-environment interactions may differ.

Key measures

16S amplicon sequencing of rhizosphere bacterial communities; Tax4Fun-predicted functional gene abundance related to drought stress; extracellular enzyme activity potentials (carbon cycle enzymes); bacterial diversity metrics; relative abundance of Gram-positive phyla

Outcomes reported

The study assessed structural and functional adaptations of rhizosphere bacterial communities in wheat under drought stress, measured via 16S amplicon sequencing, predicted drought-related functional gene abundances (Tax4Fun), and extracellular enzyme activities. Findings demonstrated that soil type, farming system (conventional vs. organic), and wheat cultivar all influenced bacterial community composition and functional responses to water scarcity.

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