Elevated CO₂ reinforces PT11-dependent symbiotic phosphate uptake to reprogram root nutrient acquisition in rice

Using split-root systems, dual radioisotope tracing, and transcriptomic profiling in wild-type and pt11 plants, we demonstrate that suppression of the direct phosphate uptake pathway occurs locally in colonized roots and requires functional symbiotic phosphate transport. In contrast, changes in root architecture — including reduced fine lateral root development — are governed by both systemic and local signals, with local regulation dependent on processes downstream of PT11.

Transcriptomic analyses identify symbiotic phosphate transport as a regulatory checkpoint that stabilizes the mycorrhizal transcriptional program and coordinates the selection of nutrient acquisition pathways under elevated CO₂. Together, these findings reveal that rising CO₂ reinforces symbiotic phosphate uptake through carbon-driven regulation, reshaping root nutrient acquisition. This work provides a mechanistic framework for integrating plant–microbe interactions into strategies aimed at sustaining crop productivity and managing carbon in a high-CO₂ world.