The transcription factor PHR1 plays a key role in the regulation of sulfate shoot-to-root flux upon phosphate starvation in Arabidopsis

Background: Sulfate and phosphate are both vital macronutrients required for plant growth and development. Despite evidence for interaction between sulfate and phosphate homeostasis, no transcriptional factor has yet been identified in higher plants that affects, at the gene expression and physiological levels, the response to both elements. This work was aimed at examining whether PHR1, a transcription factor previously shown to participate in the regulation of genes involved in phosphate homeostasis, also contributed to the regulation and activity of genes involved in sulfate inter-organ transport. Results: Among the genes implicated in sulfate transport in Arabidopsis thaliana, SULTR1;3 and SULTR3;4 showed up-regulation of transcripts in plants grown under phosphate-deficient conditions. The promoter of SULTR1;3 contains a motif that is potentially recognizable by PHR1. Using the phr1 mutant, we showed that SULTR1;3 up regulation following phosphate deficiency was dependent on PHR1. Furthermore, transcript up regulation was found in phosphate-deficient shoots of the phr1 mutant for SULTR2;1 and SULTR3;4, indicating that PHR1 played both a positive and negative role on the expression of genes encoding sulfate transporters. Importantly, both phr1 and sultr1;3 mutants displayed a reduction in their sulfate shoot-to-root transfer capacity compared to wild-type plants under phosphate-deficient conditions. Conclusions: This study reveals that PHR1 plays an important role in sulfate inter-organ transport, in particular on the regulation of the SULTR1;3 gene and its impact on shoot-to-root sulfate transport in phosphate-deficient plants. PHR1 thus contributes to the homeostasis of both sulfate and phosphate in plants under phosphate deficiency. Such a function is also conserved in Chlamydomonas reinhardtii via the PHR1 ortholog PSR1

Phosphate and zinc transport and signalling in plants: toward a better understanding of their homeostasis interaction

Zn and Pi are essential elements for plant growth. Current understanding of the regulation of their homeostasis interaction and signalling cross-talk is presente

Coordination between zinc and phosphate homeostasis involves the transcription factor PHR1, the phosphate exporter PHO1, and its homologue PHO1;H3 in Arabidopsis

Phosphate over-accumulates in shoots in response to Zn deprivation. Results shown in this article suggest key roles of PHR1 and PHO1 and a counteractive function of PHO1;H3 in controlling root-to-shoot phosphate translocation in Arabidopsi

Identification of molecular integrators shows that nitrogen activelycontrolsthephosphatestarvationresponseinplants

Nitrogen (N) and phosphorus (P) are key macronutrients sustaining plant growth and crop yield and ensuring food security worldwide. Understanding how plants perceive and interpret the combinatorial nature of these signals thus has important agricultural implications within the context of (1) increased food demand, (2) limited P supply, and (3) environmental pollution due to N fertilizer usage. Here, we report the discovery of an active control of P starvation response (PSR) by a combination of local and long-distance N signaling pathways in plants. We show that, in Arabidopsis (Arabidopsis thaliana), the nitrate transceptor CHLORINA1/NITRATE TRANSPORTER1.1 (CHL1/NRT1.1) is a component of this signaling crosstalk. We also demonstrate that this crosstalk is dependent on the control of the accumulation and turnover by N of the transcription factor PHOSPHATE STARVATION RESPONSE1 (PHR1), a master regulator of P sensing and signaling. We further show an important role of PHOSPHATE2 (PHO2) as an integrator of the N availability into the PSR since the effect of N on PSR is strongly affected in pho2 mutants. We finally show that PHO2 and NRT1.1 influence each other’s transcript levels. These observations are summarized in a model representing a framework with several entry points where N signal influence PSR. Finally, we demonstrate that this phenomenon is conserved in rice (Oryza sativa) and wheat (Triticum aestivum), opening biotechnological perspectives in crop plants.This work was supported in the Honude group (Biochemistry & Plant Molecular Physiology) by Agence Nationale de la Recherche (IMANA ANR-14-CE19-0008 with a doctoral fellowship to A.S.), by the Centre National de la Recherche Scientifique (CNRS LIA-CoopNet to G.K.), and by the National Science Foundation (NSF IOS 1339362-NutriNet). Research in V.R.’s laboratory was funded by the Ministry of Economy and Competitiveness and AEI/FEDER/European (grants BIO2013-46539-R and BIO2016-80551-R)

Regulation of phosphate starvation responses in plants: The emergence of a new signaling player

International audienc

Can we maintain plant growth capacity while decreasing nutrient accumulation? Case of phosphorus

Can we maintain plant growth capacity while decreasing nutrient accumulation? Case of phosphorus. SEB Annual Main Meeting 201

Uncoupling phosphate deficiency from its effects on growth and gene expression in plants

Uncoupling phosphate deficiency from its effects on growth and gene expression in plants. 17th International Plant Nutrition Colloquium (IPNC

Étude de la régulation de l'expression différentielle des transporteurs du sulfate SULTR1.1 et SULTR1.2 d'Arabidopsis thaliana et analyse structure-fonction du domaine STAS de SULTR1.2

Equipe Physiologie Moléculaire des PlantesNous avons étudié la régulation différentielle de l'expression de deux transporteurs à haute affinité pour le sulfate, SULTR1.1 et SULTR1.2, chez A. thaliana. Nous avons cherché à mettre en évidence des relations entre l'accumulation des transcrits SULTR1.1 et de SULTR1.2 et la teneur en sulfate et en glutathion dans les racines. Le niveau d'accumulation des transcrits SULTR1.1 et SULTR1.2 a été quantifié par une approche de Q.RT-PCR. Nos résultats montrent que i) le niveau d'accumulation des transcrits SULTR1.2 est largement superieur à celui de SULTR1.1 ii) l'expression de deux transporteurs est corrélée positivement entre eux iii) l'expression du gène SULTR1.1 est corrélée positivement à la teneur en sulfate et négativement à la teneur en glutathion dans la racine. iiii) Par contre, aucune corrélation n'a été établie entre l'accumulation des transcrits SULTR1.2 et la teneur en sulfate et en glutathion. Nous suggérons que la voie de la régulation de l'expression de SULTR1.2 est d'un type nouveau, différent de celui impliqué dans l'expression de SULTR1.1. Nous avons étudié la structure et l'importance fonctionnelle du domaine STAS(Sulfate Transporter and AntiSigma antagonist) de SULTR1.2. Le rôle du domaine STAS chez les transporteurs de sulfate est encore inconnu. La modélisation du domaine STAS de SULTR1.2 qui a été effectuée sur la base de la structure de SpoIIAA de B. subtilis, nous a permis de mettre en évidence une quasi-identité de structure entre le domaine STAS de SULTR1.2 et SpoIIAA. En s'appuyant sur ce modèle, nous avons généré des modifications structurales par mutagenèses dirigées, et analysé leurs incidences fonctionnelles en utilisant un mutant de levure comme système d'expression hétérologue. Nous avons montré que l'extension C-terminale du domaine STAS et son site potentiel de phosphorylation, sont indispensables pour la fonctionnalité de SULTR1.2. Ce travail nous a aussi permis d'émettre l'hypothèse que la régulation de la fonction de SULTR1.2 pourrait dépendre du statut de phosphorylation du domaine STAS