ER-resident proteins PDR2 and LPR1 mediate the developmental response of root meristems to phosphate availability.
Inadequate availability of inorganic phosphate (Pi) in the rhizosphere is a common challenge to plants, which activate metabolic and developmental responses to maximize Pi acquisition. The sensory mechanisms that monitor environmental Pi status and regulate root growth via altered meristem activity are unknown. Here, we show that PHOSPHATE DEFICIENCY RESPONSE 2 (PDR2) encodes the single P(5)-type ATPase of Arabidopsis thaliana. PDR2 functions in the endoplasmic reticulum (ER) and is required for proper expression of SCARECROW (SCR), a key regulator of root patterning, and for stem-cell maintenance in Pi-deprived roots. We further show that the multicopper oxidase encoded by LOW PHOSPHATE ROOT 1 (LPR1) is targeted to the ER and that LPR1 and PDR2 interact genetically. Because the expression domains of both genes overlap in the stem-cell niche and distal root meristem, we propose that PDR2 and LPR1 function together in an ER-resident pathway that adjusts root meristem activity to external Pi. Our data indicate that the Pi-conditional root phenotype of pdr2 is not caused by increased Fe availability in low Pi; however, Fe homeostasis modifies the developmental response of root meristems to Pi availability.
Ticconi
Carla A
CA
Department of Plant Sciences, University of California, One Shields Avenue, Davis, CA 95616, USA.
Lucero
Rocco D
RD
Sakhonwasee
Siriwat
S
Adamson
Aaron W
AW
Creff
Audrey
A
Nussaume
Laurent
L
Desnos
Thierry
T
Abel
Steffen
S
D000251:Adenosine Triphosphatases / Q000096:biosynthesis / Q000502:physiology*; D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000096:biosynthesis / Q000378:metabolism* / Q000502:physiology; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D047468:Immunoprecipitation; D018519:Meristem / Q000502:physiology*; D018613:Microscopy, Confocal / Q000379:methods; D008954:Models, Biological; D008957:Models, Genetic; D010088:Oxidoreductases / Q000096:biosynthesis / Q000378:metabolism / Q000502:physiology*; D010641:Phenotype; D010710:Phosphates / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000378:metabolism
D029681:Arabidopsis Proteins; D010710:Phosphates; C543910:LPR1 protein, Arabidopsis; D010088:Oxidoreductases; C024748:copper oxidase; D000251:Adenosine Triphosphatases; C543909:PDR2 protein, Arabidopsis