Integrated multi-omics analysis reveals coordinated root and rhizosphere responses underlying AMF-mediated drought tolerance in kiwifruit.

Abstract

Drought stress substantially restricts kiwifruit (Actinidia spp.) growth and productivity, yet the mechanisms through which arbuscular mycorrhizal fungi (AMF) promote drought tolerance remain insufficiently understood. To address this gap, root physiological and molecular analyses were integrated with multi-omics profiling of the rhizosphere microbiome to investigate AMF-mediated drought responses under well-watered and drought-stress conditions. Under drought stress, AMF inoculation improved plant growth, root development, cellular ultrastructure, and physiological performance. More importantly, root omics analysis revealed coordinated regulation of drought-responsive pathways involving glutathione metabolism, amino acid biosynthesis, phytohormone regulation, and energy metabolism. Beyond these plant responses, AMF inoculation altered bacterial and fungal community composition, enriched potentially beneficial taxa, and increased rhizosphere network connectivity under drought stress. Within the restructured microbiome, we identified an AMF-specific drought-responsive amplicon sequence variant (ASV) module composed primarily of bacterial taxa and associated with cross-kingdom microbial interactions. Integrated microbial-metabolite network analysis further identified a metabolite feature annotated as 1-piperideine as a candidate associated with selective microbial recruitment in AMF-colonized rhizospheres. Together, these findings suggest that AMF-associated drought tolerance in kiwifruit involves complementary changes in plant physiology, root molecular responses, and rhizosphere microbiome assembly. A mechanistic basis is thereby provided for developing AMF-based strategies to improve kiwifruit production under increasing water limitation.