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ARS Home » Northeast Area » Ithaca, New York » Robert W. Holley Center for Agriculture & Health » Plant, Soil and Nutrition Research » Research » Publications at this Location » Publication #319636
Title: Plant vasculature-mediated signaling involved in early phosphate stress response

Author
item ZHANG, ZHAOLIANG - University Of California
item ZHENG, YI - Boyce Thompson Institute
item HAM, BYUNG-KOOK - University Of California
item CHEN, JIEYU - University Of California
item YOSHIDA, AKIKO - University Of California
item Kochian, Leon
item FEI, ZHANGJUN - Boyce Thompson Institute
item LUCAS, BILL - University Of California

Submitted to: Nature Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/4/2016
Publication Date: 4/6/2016
Citation: Zhang, Z., Zheng, Y., Ham, B., Chen, J., Yoshida, A., Kochian, L.V., Fei, Z., Lucas, B. 2016. Plant vasculature-mediated signaling involved in early phosphate stress response. Nature Plants. doi: 10.1038/nplants.2016.33.

Interpretive Summary: Phosphorus (P) is probably the most limiting mineral nutrient for plants. Many of our planet’s soils are low in phosphorus, and this includes approximately half of the world’s agricultural lands. Hence, there is considerable interest in developing plant varieties that are more phosphorus efficient - that is, crops that can produce higher yields while using less soil phosphorus. Furthermore, in developed country agriculture P fertilizer not taken up by crop plants ends up polluting ground and surface waters and this is a growing problem in the US. Research on plant response to low P suggest there are sophisticated systemic signaling systems between the plant shoot and root that controls phosphate (Pi) stress responses and Pi homeostasis. In this study, we have identified both the nature of the phosphate (Pi) stress related root-to-shoot signaling agents and the shoot vascular system as the tissue that perceives and responds to these signals through the delivery of thousands of mRNAs that are targeted to specific sinks. These results provide important insights into the systemic signaling systems, employed by plants, to facilitate an interactive response between the soil solution the root and shoot organs to optimize Pi acquisition and allocation to support growth in the presence of limited Pi availability within the soil. These discoveries will set the stage for future discoveries that will ultimately provide plant breeders with the molecular targets for improving crop P efficiency via molecular-assisted breeding.

Technical Abstract: Depletion of finite global rock phosphate (Pi) reserves will impose major limitations on future agricultural productivity and food security. Hence, modern breeding programs seek to develop Pi-efficient crops with sustainable yields under reduced Pi fertilizer inputs. In this regard, although the long-term responses of plants to Pi stress are well documented, the early signaling events have yet to be elucidated. Here, we show that Pi and the phytohormones, cytokinin and gibberellin, function as root-to-shoot Pi stress signals that are perceived in the shoot by vascular cells. We further show that Pi stress induces rapid and major changes in the phloem mRNA population, and grafting studies revealed that thousands of these mRNAs are delivered to specific sink tissues. Thus, the shoot vascular system acts as the site of root-derived Pi stress perception, and the phloem serves to deliver a cascade of signals to various sinks, presumably to coordinate whole-plant Pi homeostasis.