ZmPT7 Regulates Nitrate Utilization in Maize by Interacting With ZmNRT2.2

Nitrogen and phosphorus constitute essential elements that play pivotal roles in plant growth and development. Nevertheless, the molecular mechanisms that underpin the intricate cross-talk between nitrogen and phosphorus in maize have not been fully deciphered. In the present study, the phosphate transporter ZmPT7 gene was identified and isolated through a reverse genetic screening approach, specifically targeting mutants that exhibited sensitivity to low nitrate (NO₃ ^-). Subsequently, the functions of ZmPT7 were probed and analyzed in-depth using data-independent acquisition (DIA)-based quantitative proteomics, followed by a series of comprehensive validation experiments. It was revealed that, although ZmPT7 does not independently act as a NO₃ ^- transporter, it actively participates in an interaction with ZmNRT2.2. This interaction leads to the enhancement of the protein abundance of ZmNRT2.2, thereby effectively modulating NO₃ ^- uptake under conditions of limited NO₃ ^- availability. This significant discovery substantially contributes to the elucidation and clarification of the molecular mechanisms that govern the coordinated cross-talk between nitrogen and phosphorus in maize during its adaptation to NO₃ ^- deficiency. Consequently, it enriches our understanding of the survival strategies and adaptive mechanisms employed by this important crop species, providing valuable insights for further research and agricultural applications.