Control of plant phosphate homeostasis by inositol pyrophosphates and the SPX domain.

Ji-Yul Jung, Martina K Ried, Michael Hothorn, Yves Poirier

Journal: Current opinion in biotechnology 2018;49():156-162

PMID: 28889038

Abstract

Proteins containing a SPX domain are involved in phosphate (Pi) homeostasis, including Pi transport and adaptation to Pi deficiency. The SPX domain harbors a basic surface binding Pi at low affinity and inositol pyrophosphates (PP-InsPs) at high affinity. Genetic and biochemical studies revealed that PP-InsPs serve as ligands for the SPX domain. Residues in the PHO1 SPX domain involved in PP-InsPs binding are critical for its Pi export activity, and the interaction between SPX proteins and the PHR1 transcription factor, which results in PHR1 inactivation, is promoted by PP-InsPs. Changes in PP-InsPs levels in response to Pi deficiency may thus contribute to the adaptation of plants to stress via the modulation of the activity of SPX-containing proteins and their interactors. Modulating PP-InsP levels or the affinity/specificity of the SPX domain for PP-InsP could potentially be used to engineer crops to maintain high yield under reduced Pi fertilizer input.

Address: Department of Plant Molecular Biology, University of Lausanne, Lausanne, Switzerland.; Structural Plant Biology Laboratory, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland.; Structural Plant Biology Laboratory, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland. Electronic address: [email protected].; Department of Plant Molecular Biology, University of Lausanne, Lausanne, Switzerland. Electronic address: [email protected].

DOI: 10.1016/j.copbio.2017.08.012