Plant-Microbe Interactions in Sorghum Nutrient Acquisition: Roles of Rhizosphere Microbes and N, P, and K Transporters.

Sorghum bicolor is an important cereal crop because of its tolerance to drought, high temperature, and low input requirements. However, the low productivity of sorghum is still due to the inadequate nutrient status and inappropriate use of nitrogen (N), phosphorus (P), and potassium (K). These nutrients are essential for plant growth, metabolism, abiotic stress tolerance, and yield development. Nutrient uptake in sorghum is regulated by the plant, the rhizosphere microbiome, and close interactions between the root system and membrane-localized transporter systems. This review summarizes the molecular interaction between the root and microbes that control the N, P, and K transporter genes in sorghum. It initially describes the architecture of sorghum roots, root exudation, and the key elements that govern rhizosphere microbiome assembly. It goes on to explain the molecular structure of significant nutrient transport systems, such as nitrate, ammonium, phosphate, and potassium transporters. Other important microbial groups related to nutrient uptake identified include diazotrophs, phosphate-solubilizing, potassium-mobilizing, and arbuscular mycorrhizal fungi. The focus is specifically on the interaction of plants and microbes that affect transporter gene expression and symbiotic acquisition of nutrients. In general, the review highlights an integrated framework of the interaction of root characteristics, microbial communities, and transporter networks in the process of controlling nutrient uptake in sorghum, and it determines valuable directions for future studies and crop enhancement.