The plant stress hormone ethylene controls floral transition via DELLA-dependent regulation of floral meristem-identity genes.
The length of the Arabidopsis thaliana life cycle depends on the timing of the floral transition. Here, we define the relationship between the plant stress hormone ethylene and the timing of floral initiation. Ethylene signaling is activated by diverse environmental stresses, but it was not previously clear how ethylene regulates flowering. First, we show that ethylene delays flowering in Arabidopsis, and that this delay is partly rescued by loss-of-function mutations in genes encoding the DELLAs, a family of nuclear gibberellin (GA)-regulated growth-repressing proteins. This finding suggests that ethylene may act in part by modulating DELLA activity. We also show that activated ethylene signaling reduces bioactive GA levels, thus enhancing the accumulation of DELLAs. Next, we show that ethylene acts on DELLAs via the CTR1-dependent ethylene response pathway, most likely downstream of the transcriptional regulator EIN3. Ethylene-enhanced DELLA accumulation in turn delays flowering via repression of the floral meristem-identity genes LEAFY (LFY) and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1). Our findings establish a link between the CTR1/EIN3-dependent ethylene and GA-DELLA signaling pathways that enables adaptively significant regulation of plant life cycle progression in response to environmental adversity.
Achard
Patrick
P
Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UJ, UK.
Baghour
Mourad
M
Chapple
Andrew
A
Hedden
Peter
P
Van Der Straeten
Dominique
D
Genschik
Pascal
P
Moritz
Thomas
T
Harberd
Nicholas P
NP
D017360:Arabidopsis / Q000378:metabolism / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins; D005030:Ethylenes / Q000378:metabolism / Q000494:pharmacology*; D035264:Flowers / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D005875:Gibberellins / Q000378:metabolism; D015151:Immunoblotting; D026161:MADS Domain Proteins / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism / Q000494:pharmacology*; D012097:Repressor Proteins / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology*; D014157:Transcription Factors / Q000378:metabolism
C419046:AGL20 protein, Arabidopsis; D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C106987:EIN3 protein, Arabidopsis; D005030:Ethylenes; D005875:Gibberellins; C074747:LFY protein, Arabidopsis; D026161:MADS Domain Proteins; D009687:Nuclear Proteins; D010937:Plant Growth Regulators; D012097:Repressor Proteins; C101465:SPY protein, Arabidopsis; D014157:Transcription Factors; C036216:ethylene