Red soil occupies an important position in China's agriculturally cultivated land resources. However, its low pH value, high aluminum concentration, and inefficient phosphorus utilization limit the productivity of acidic red soil farmland. Plant roots exhibit remarkable plasticity, capable of absorbing water and nutrients and modulating root system architecture in response to biotic and abiotic stresses, either autonomously or through rhizosphere microorganisms. This study primarily investigates the regulatory effects of rhizosphere microorganisms, including plant growth-promoting rhizobacteria, such as arbuscular mycorrhizal fungi and rhizobia, and synthetic microbial consortia, on plant root system architecture. These regulatory mechanisms encompass the production of hormones, the release of volatile organic compounds, nitrogen fixation, phosphorus solubilization, and the improvement of rhizospheric soil structure. Such mechanisms can influence root biomass, branching, lateral roots, and root hair growth. Furthermore, we summarize new visualization methods for plant root system architecture and rhizosphere microorganisms, providing technical support for studying the regulation of root system architecture by rhizosphere microbes. Under acidic soil conditions, rhizosphere microorganisms serve as a crucial regulatory strategy. By adjusting plant root system architecture, they can enhance the productivity of acidic soils, representing a potential solution for ameliorating the constraints of acidic soils.
Keywords: X-ray CT; acidic soil; aluminum toxicity; rhizosphere microorganisms; root system architecture（RSA）.