Soil Microbiota Modulates Root Transcriptome With Divergent Effect on Maize Growth Under Low and High Phosphorus Inputs

Plant growth can be promoted by beneficial microorganisms, or inhibited by detrimental ones. Although the interaction process between a single microbial species and its host has been extensively studied, the growth and transcriptional response of the host to soil microbiota is poorly understood. We planted maize in natural or sterile soil collected from a long-term experimental site with two different soil phosphate (P) regimes. We examined the composition of microbial communities inhabiting root-associated niches in natural soil. In parallel, we determined the biomass, ionomes, and root transcriptome profiling of maize grown in natural or sterile soil. Soil microbiota could promote or inhibit different P starvation-responsive (PSR) genes, as well as induce several defense-related metabolic processes independently of external P levels. Soil microbiota accompanied by long-term application of P fertilizer induced lower intensity of PSR and defense responses, inhibiting maize growth. Under a low P regime, the PSR and defense responses were induced to a higher extent, promoting P absorption and growth. Our findings suggest a soil P-dependent effect of microbiota on maize growth by integrating PSR and defense responses and provide a more refined understanding of the interaction between root growth and soil microbiota.