Low phosphate activates STOP1-ALMT1 to rapidly inhibit root cell elongation

Coline Balzergue (1, 2) , Thibault Dartevelle (1, 2) , Christian Godon (1, 3) , Edith Laugier (4) , Claudia Meisrimler (1) , Jean-Marie Teulon (5) , Audrey Creff (1) , Marie Bissler (1) , Corinne Brouchoud (1, 2) , Agnès Hagège , Jens Müller (6) , Serge Chiarenza (1, 2) , Hélène Javot (3, 1) , Noëlle Becuwe-Linka (1, 2) , Pascale David (1, 2) , Benjamin Peret (4, 4) , Etienne Delannoy (1) , Marie-Christine Thibaud (1, 2) , J. Armengaud (7) , Steffen Abel (6) , Jean-Luc Pellequer (5) , Laurent Nussaume (2, 1, 3) , Thierry Desnos (1, 2)

1 BIAM - Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB)
2 BVME - Biologie végétale et microbiologie environnementale - UMR7265
3 PEPSS - Plant Environmental Physiology and Stress Signaling
4 BPMP - Biochimie et Physiologie Moléculaire des Plantes
5 IBS - UMR 5075 - Institut de biologie structurale
6 Leibniz-Institut für Pflanzenbiochemie
7 LI2D - Laboratoire Innovations technologiques pour la Détection et le Diagnostic

Environmental cues profoundly modulate cell proliferation and cell elongation to inform and direct plant growth and development. External phosphate (Pi) limitation inhibits primary root growth in many plant species. However, the underlying Pi sensory mechanisms are unknown. Here we genetically uncouple two Pi sensing pathways in the root apex of Arabidopsis thaliana. First, the rapid inhibition of cell elongation in the transition zone is controlled by transcription factor STOP1, by its direct target, ALMT1, encoding a malate channel, and by ferroxidase LPR1, which together mediate Fe and peroxidase-dependent cell wall stiffening. Second, during the subsequent slow inhibition of cell proliferation in the apical meristem, which is mediated by LPR1-dependent, but largely STOP1–ALMT1-independent, Fe and callose accumulate in the stem cell niche, leading to meristem reduction. Our work uncovers STOP1 and ALMT1 as a signalling pathway of low Pi availability and exuded malate as an unexpected apoplastic inhibitor of root cell wall expansion.

Domains: Life Sciences [q-bio]; Vegetal Biology; Botanics

Coline Balzergue, Thibault Dartevelle, Christian Godon, Edith Laugier, Claudia Meisrimler, et al.. Low phosphate activates STOP1-ALMT1 to rapidly inhibit root cell elongation. Nature Communications, 2017, 8, pp.15300. ⟨10.1038/ncomms15300⟩. ⟨hal-01670684⟩