MOTHER-OF-FT-AND-TFL1 represses seed germination under far-red light by modulating phytohormone responses in Arabidopsis thaliana

Fabian Emmanuel Vaistij, Thiago Barros Galvão, Adama Cole, Alison D. Gilday, Zhesi He, Yi Li, David Harvey, Tony R Larson, Ian Alexander Graham

Research output: Contribution to journalArticlepeer-review

Abstract

Seed germination in many plant species is triggered by sunlight, which is rich in the red (R) wavelength and repressed by under-the-canopy light rich in far red (FR). R:FR ratios are sensed by phytochromes to regulate levels of gibberellins (GAs) and abscisic acid (ABA), which induce and inhibit germination respectively. In this study we have discovered that, under FR light conditions, germination is repressed by MOTHER-OF-FT-AND-TFL1 (MFT) through the regulation of the ABA and GA signaling pathways. We also show that MFT gene expression is tightly regulated by light quality. Previous work has shown that under FR light conditions the transcription factor PHYOCHROME-INTERACTING-FACTOR1 (PIF1) accumulates and promotes expression of SOMNUS (SOM) that, in turn, leads to increased ABA and decreased GA levels. PIF1 also promotes expression of genes encoding ABA-INSENSITIVE5 (ABI5) and DELLA growth-repressor proteins, which act in the ABA and GA signaling pathways, respectively. Here we show that MFT gene expression is promoted by FR light through the PIF1/SOM/ABI5/DELLA pathway and is repressed by R light via the transcription factor SPATULA (SPT). Consistent with this, we also show that SPT gene expression is repressed under FR light in a PIF1-dependent manner. Furthermore, transcriptomic analyses presented in this study indicate that MFT exerts its function by promoting expression of known ABA-induced genes and repressing cell wall expansion-related genes.

Original languageEnglish
Pages (from-to)8442-8447
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume115
Issue number33
Early online date30 Jul 2018
Publication statusPublished - 14 Aug 2018

Bibliographical note

© 2018 the Author(s).

Publisher Copyright:
© 2018 National Academy of Sciences. All rights reserved.

Copyright © 2018 the Author(s). Published by PNAS.

Keywords

  • Abscisic acid
  • Far-red light
  • Gibberellin
  • PIF1
  • Seed germination
  • Arabidopsis Proteins/genetics
  • Basic-Leucine Zipper Transcription Factors/genetics
  • Germination/physiology
  • Plant Growth Regulators/physiology
  • Signal Transduction/physiology
  • Carrier Proteins/genetics
  • Light
  • Arabidopsis/physiology
  • Gibberellins/physiology
  • Abscisic Acid/physiology
  • Basic Helix-Loop-Helix Transcription Factors/physiology

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