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

TY - JOUR

T1 - MOTHER-OF-FT-AND-TFL1 represses seed germination under far-red light by modulating phytohormone responses in Arabidopsis thaliana

AU - Vaistij, Fabian Emmanuel

AU - Barros Galvão, Thiago

AU - Cole, Adama

AU - Gilday, Alison D.

AU - He, Zhesi

AU - Li, Yi

AU - Harvey, David

AU - Larson, Tony R

AU - Graham, Ian Alexander

N1 - © 2018 the Author(s). Publisher Copyright: © 2018 National Academy of Sciences. All rights reserved. Copyright © 2018 the Author(s). Published by PNAS.

PY - 2018/8/14

Y1 - 2018/8/14

N2 - 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.

AB - 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.

KW - Abscisic acid

KW - Far-red light

KW - Gibberellin

KW - PIF1

KW - Seed germination

KW - Arabidopsis Proteins/genetics

KW - Basic-Leucine Zipper Transcription Factors/genetics

KW - Germination/physiology

KW - Plant Growth Regulators/physiology

KW - Signal Transduction/physiology

KW - Carrier Proteins/genetics

KW - Light

KW - Arabidopsis/physiology

KW - Gibberellins/physiology

KW - Abscisic Acid/physiology

KW - Basic Helix-Loop-Helix Transcription Factors/physiology

UR - http://www.scopus.com/inward/record.url?scp=85052754956&partnerID=8YFLogxK

M3 - Article

C2 - 30061395

SN - 0027-8424

VL - 115

SP - 8442

EP - 8447

JO - Proceedings of the National Academy of Sciences of the United States of America

JF - Proceedings of the National Academy of Sciences of the United States of America

IS - 33

ER -