Progress on mechanism on the phosphorus-efficient absorption and utilization in wheat (Triticum aestivum L.)

Wheat is a high phosphorus (P)-demanding cereal crop, and its stable and high yield relies heavily on substantial phosphorus fertilizer input. However, the seasonal utilization efficiency of phosphorus fertilizer in Chinese wheat production is only 19%, making the improvement of phosphorus absorption and use efficiency a critical scientific issue in wheat nutrient management research. Based on our previous research on wheat P use efficiency, in this review, we first analyze the reasons for the low P efficiency in soil and summarize five main pathways for uptake and utilizing P in wheat and other crops: root morphological remodeling, organic acid secretion, internal P redistribution and gene expression. Among the P-efficient genes, we emphasize the categories and functions of wheat high affinity P transporter genes (TaPHT1s). Subsequently, we introduce the calculation formulas for P absorption efficiency and utilization efficiencies, explain the main reasons for the slow progress in mapping and cloning P-efficient genes via forward genetics, and summarize the identified Pi-efficient candidate genes via reverse genetics approaches. On the wheat P-efficient molecular regulatory signaling pathway, we describe the functions and mechanisms of several transcription factors including TaPHR1, TaMYB4. Finally, we propose future directions to accelerate the cloning of P-efficient genes in wheat, including developing high-throughput phenotyping platforms for P efficiency; identifying key PHT genes involved in P utilization efficiency among tissues after anthesis; and leveraging wheat genome sequencing data and high-throughput microarrays