Membrane-associated Transcription Factor Peptidase, site-2 Protease, Antagonizes ABA Signaling in Arabidopsis

New Phytol. 2015 Oct;208(1):188-97. doi: 10.1111/nph.13436. Epub 2015 Apr 28.

Abstract

Abscisic acid plays important roles in maintaining seed dormancy while gibberellins (GA) and other phytohormones antagonize ABA to promote germination. However, how ABA signaling is desensitized during the transition from dormancy to germination is still poorly understood. We functionally characterized the role of membrane-associated transcription factor peptidase, site-2 protease (S2P), in ABA signaling during seed germination in Arabidopsis. Genetic analysis showed that loss-of-function of S2P conferred high ABA sensitivity during seed germination, and expression of the activated form of membrane-associated transcription factor bZIP17, in which the transmembrane domain and endoplasmic reticulum (ER) lumen-facing C-terminus were deleted, in the S2P mutant rescued its ABA-sensitive phenotype. MYC and green fluorescent protein (GFP)-tagged bZIP17 were processed and translocated from the ER to the nucleus in response to ABA treatment. Furthermore, genes encoding negative regulators of ABA signaling, such as the transcription factor ATHB7 and its target genes HAB1, HAB2, HAI1 and AHG3, were up-regulated in seeds of the wild-type upon ABA treatment; this up-regulation was impaired in seeds of S2P mutants. Our results suggest that S2P desensitizes ABA signaling during seed germination through regulating the activation of the membrane-associated transcription factor bZIP17 and therefore controlling the expression level of genes encoding negative regulators of ABA signaling.

Keywords: ABA response; Arabidopsis; membrane-associated transcription factor; regulated intramembrane proteolysis; seed germination; site-2 peptidase (S2P).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abscisic Acid / metabolism*
  • Arabidopsis / enzymology
  • Arabidopsis / genetics*
  • Arabidopsis / metabolism
  • Arabidopsis Proteins / metabolism
  • Base Sequence
  • Basic-Leucine Zipper Transcription Factors / metabolism
  • Biological Transport
  • Gene Expression Regulation, Developmental
  • Gene Expression Regulation, Plant*
  • Genes, Plant*
  • Germination / genetics
  • Membrane Proteins / metabolism
  • Molecular Sequence Data
  • Peptide Hydrolases / genetics
  • Peptide Hydrolases / metabolism*
  • Plant Development / genetics
  • Plant Dormancy / genetics
  • Plant Growth Regulators / metabolism
  • Seeds / growth & development*
  • Seeds / metabolism
  • Signal Transduction
  • Transcription Factors / metabolism*
  • Up-Regulation

Substances

  • Arabidopsis Proteins
  • Basic-Leucine Zipper Transcription Factors
  • Membrane Proteins
  • Plant Growth Regulators
  • Transcription Factors
  • bZIP17 protein, Arabidopsis
  • Abscisic Acid
  • Peptide Hydrolases

Associated data

  • GENBANK/KR054754