A reduced-function allele reveals that EARLY FLOWERING3 repressive action on the circadian clock is modulated by phytochrome signals in Arabidopsis

TY - JOUR

T1 - A reduced-function allele reveals that EARLY FLOWERING3 repressive action on the circadian clock is modulated by phytochrome signals in Arabidopsis

AU - Kolmos, Elsebeth

AU - Herrero, Eva

AU - Bujdoso, Nora

AU - Millar, Andrew J

AU - Tóth, Réka

AU - Gyula, Peter

AU - Nagy, Ferenc

AU - Davis, Seth J

PY - 2011/9

Y1 - 2011/9

N2 - Arabidopsis thaliana EARLY FLOWERING3 (ELF3) is essential for the generation of circadian rhythms. ELF3 has been proposed to restrict light signals to the oscillator through phytochrome photoreceptors, but that has not been explicitly shown. Furthermore, the genetic action of ELF3 within the clock had remained elusive. Here, we report a functional characterization of ELF3 through the analysis of the elf3-12 allele, which encodes an amino acid replacement in a conserved domain. Circadian oscillations persisted, and unlike elf3 null alleles, elf3-12 resulted in a short circadian period only under ambient light. The period shortening effect of elf3-12 was enhanced by the overexpression of phytochromes phyA and phyB. We found that elf3-12 was only modestly perturbed in resetting of the oscillator and in gating light-regulated gene expression. Furthermore, elf3-12 essentially displayed wild-type development. We identified targets of ELF3 transcriptional repression in the oscillator, highlighting the action at the morning gene PSEUDO-RESPONSE REGULATOR9. Taken together, we identified two separable roles for ELF3, one affecting the circadian network and the other affecting light input to the oscillator. This is consistent with a dual function of ELF3 as both an integrator of phytochrome signals and a repressor component of the core oscillator.

AB - Arabidopsis thaliana EARLY FLOWERING3 (ELF3) is essential for the generation of circadian rhythms. ELF3 has been proposed to restrict light signals to the oscillator through phytochrome photoreceptors, but that has not been explicitly shown. Furthermore, the genetic action of ELF3 within the clock had remained elusive. Here, we report a functional characterization of ELF3 through the analysis of the elf3-12 allele, which encodes an amino acid replacement in a conserved domain. Circadian oscillations persisted, and unlike elf3 null alleles, elf3-12 resulted in a short circadian period only under ambient light. The period shortening effect of elf3-12 was enhanced by the overexpression of phytochromes phyA and phyB. We found that elf3-12 was only modestly perturbed in resetting of the oscillator and in gating light-regulated gene expression. Furthermore, elf3-12 essentially displayed wild-type development. We identified targets of ELF3 transcriptional repression in the oscillator, highlighting the action at the morning gene PSEUDO-RESPONSE REGULATOR9. Taken together, we identified two separable roles for ELF3, one affecting the circadian network and the other affecting light input to the oscillator. This is consistent with a dual function of ELF3 as both an integrator of phytochrome signals and a repressor component of the core oscillator.

UR - http://www.scopus.com/inward/record.url?scp=80055024623&partnerID=8YFLogxK

U2 - 10.1105/tpc.111.088195

DO - 10.1105/tpc.111.088195

M3 - Article

C2 - 21908721

SN - 1040-4651

VL - 23

SP - 3230

EP - 3246

JO - The Plant Cell

JF - The Plant Cell

IS - 9

ER -