Circadian control of abscisic acid biosynthesis and signalling pathways revealed by genome-wide analysis of LHY binding targets.
New Phytol
; 220(3): 893-907, 2018 11.
Article
en En
| MEDLINE
| ID: mdl-30191576
ABSTRACT
The LATE ELONGATED HYPOCOTYL (LHY) transcription factor functions as part of the oscillatory mechanism of the Arabidopsis circadian clock. This paper reports the genome-wide analysis of its binding targets and reveals a role in the control of abscisic acid (ABA) biosynthesis and downstream responses. LHY directly repressed expression of 9-cis-epoxycarotenoid dioxygenase enzymes, which catalyse the rate-limiting step of ABA biosynthesis. This suggested a mechanism for the circadian control of ABA accumulation in wild-type plants. Consistent with this hypothesis, ABA accumulated rhythmically in wild-type plants, peaking in the evening. LHY-overexpressing plants had reduced levels of ABA under drought stress, whereas loss-of-function mutants exhibited an altered rhythm of ABA accumulation. LHY also bound the promoter of multiple components of ABA signalling pathways, suggesting that it may also act to regulate responses downstream of the hormone. LHY promoted expression of ABA-responsive genes responsible for increased tolerance to drought and osmotic stress but alleviated the inhibitory effect of ABA on seed germination and plant growth. This study reveals a complex interaction between the circadian clock and ABA pathways, which is likely to make an important contribution to plant performance under drought and osmotic stress conditions.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Factores de Transcripción
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Transducción de Señal
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Ritmo Circadiano
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Arabidopsis
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Ácido Abscísico
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Genoma de Planta
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Proteínas de Unión al ADN
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Vías Biosintéticas
Idioma:
En
Revista:
New Phytol
Asunto de la revista:
BOTANICA
Año:
2018
Tipo del documento:
Article
País de afiliación:
Reino Unido