System Level Understanding of Zinc and Phosphate Signalling Crosstalk – PHLOWZ

Although some regulators have recently been identified, most of the molecular players involved early on in this pathway remain unknown. The PHLOWZ project proposes to elucidate the primary events of this pathway in Arabidopsis, using Zn and Pi homeostasis imaging and transcriptomics approaches. By combining this work with reverse genetics approaches, PHLOWZ aims to identify new regulators of Zn/Pi signaling and overcome the obstacles that limit Pi uptake in plants.

The expression of a large number of genes was found to be affected early on in response to low Zn availability, and we were able to identify certain genes whose induction correlated with increased Pi accumulation. The functional characterization of a selection of these genes is aimed at better understanding their role in Zn deficiency, in particular their possible involvement in stimulating Pi accumulation.
To advance our understanding of the response to this deficiency, the project partners have developed several innovative cellular imaging tools to visualize the regulation of genes or transporters linked to Zn, metal or Pi homeostasis.

PHLOWZ aims to identify new players and regulatory nodes in Zn/Pi signaling in plants, in a fundamental research perspective. In the longer term, this knowledge will be helpful in opening up new agronomic strategies, to better match the use of fertilizers to the diversity of soil compositions.

The technological developments associated with this project have already resulted in two publications (Hani 2021; Sadoine 2020). In addition, focusing on the link between metals (Zn in particular) and Pi has resulted in the publication of several review articles revues (Assunção 2022 ; Cho 2022 et 2021 ; Hanikenne 2020 ; Lešková 2022 ; Robe 2021), which will be followed by other publications describing the new mechanisms identified during this project.

Phosphate (Pi), a major cell component, is a strategically important plant resource due to the impending shortage of high-quality sources of this element. Diminishing the use of Pi in crop production requires a better understanding of the factors that stimulate Pi uptake. It has been widely observed that plants exposed to Pi and Zinc (Zn) deficiencies accumulate more Pi than when they are in more Zn-rich soils. Current data suggest that a specific signaling pathway is involved in the crosstalk between Pi and Zn homeostasis. Although some regulators have been identified recently, most of the early players involved in this pathway remain unknown. The PHLOWZ project aims to clarify the early events involved in this crosstalk, using live imaging of changes in Zn and Pi homeostasis and transcriptomics. PHLOWZ will combine these results with the power of GWAS studies and reverse genetics to identify new early players and regulatory nodes of the Zn/Pi pathway. The discovery of these regulators will have great significance for basic research and agronomical applications.