A plasma membrane transporter coordinates phosphate reallocation and grain filling in cereals

Nat Genet. 2021 Jun;53(6):906-915. doi: 10.1038/s41588-021-00855-6. Epub 2021 Apr 29.

Abstract

Phosphate (Pi) is essential to plant growth and crop yield. However, it remains unknown how Pi homeostasis is maintained during cereal grain filling. Here, we identified a rice grain-filling-controlling PHO1-type Pi transporter, OsPHO1;2, through map-based cloning. Pi efflux activity and its localization to the plasma membrane of seed tissues implicated a specific role for OsPHO1;2 in Pi reallocation during grain filling. Indeed, Pi over-accumulated in developing seeds of the Ospho1;2 mutant, which inhibited the activity of ADP-glucose pyrophosphorylase (AGPase), important for starch synthesis, and the grain-filling defect was alleviated by overexpression of AGPase in Ospho1;2-mutant plants. A conserved function was recognized for the maize transporter ZmPHO1;2. Importantly, ectopic overexpression of OsPHO1;2 enhanced grain yield, especially under low-Pi conditions. Collectively, we discovered a mechanism underlying Pi transport, grain filling and P-use efficiency, providing an efficient strategy for improving grain yield with minimal P-fertilizer input in cereals.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Cell Membrane / metabolism*
  • Cell Membrane / ultrastructure
  • Chromosome Mapping
  • Edible Grain / metabolism*
  • Edible Grain / ultrastructure
  • Gene Expression Regulation, Plant
  • HEK293 Cells
  • Humans
  • Membrane Transport Proteins / metabolism*
  • Mutation / genetics
  • Oryza / enzymology
  • Oryza / genetics
  • Phenotype
  • Phosphates / metabolism*
  • Plant Proteins / genetics
  • Plant Proteins / metabolism
  • Plants, Genetically Modified
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Seeds / genetics
  • Seeds / ultrastructure
  • Starch / biosynthesis
  • Xenopus
  • Zea mays / genetics

Substances

  • Membrane Transport Proteins
  • Phosphates
  • Plant Proteins
  • RNA, Messenger
  • Starch