Long-distance signal transduction of nitrogen and phosphorus in plants

In response to varied nutrient availability in soil, plants exhibit high physiological and developmental plasticity to integrate and coordinate the information of nutrient sensing between shoots and roots, and systematically regulate the whole-plant nutrient response and growth and development. This signal transduction process largely relies on the transportation of signal molecules via vascular systems, so-called long-distance signaling. Although plants require numerous mineral elements from the soil, the major nutrients that limit plant productivity are nitrogen (N) and phosphorus (P). Recent studies have elucidated that various mobile signals, such as small proteins, peptides, and microRNAs, are responsible for long-distance signaling of N and P. Here, we summarize the long-distance signal molecules identified in N and P nutrition and their related signal transduction mechanisms, provide an overview of the influence of light signals on the long-distance signal of N and P, and also discuss the future research direction of long-distance signals.