Faculty Opinions recommendation of Arabidopsis SPA proteins regulate photoperiodic flowering and interact with the floral inducer CONSTANS to regulate its stability.

Plants use the circadian clock as a timekeeping mechanism to regulate photoperiodic flowering in response to the seasonal changes. CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1), initially identified as a central repressor of seedling photomorphogenesis, was recently shown to be involved in the regulation of light input to the circadian clock, modulating the circadian rhythm and flowering. COP1 encodes a RING-finger E3 ubiquitin ligase and works in concert with SUPPRESSOR of phyA-105 (SPA) proteins to repress photoperiodic flowering by regulating proteasome-mediated degradation of CONSTANS (CO), a central regulator of photoperiodic flowering. In addition, COP1 and EARLY FLOWERING 3 (ELF3) indirectly modulate CO expression via the degradation of GIGANTEA (GI). Here, we summarize the current understanding of the molecular mechanisms underlying COP1’s role in controlling of photoperiodic flowering.

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Arabidopsis SPA proteins regulate photoperiodic flowering and interact with the floral inducer CONSTANS to regulate its stability

Development ◽

10.1242/dev.02661 ◽

2006 ◽

Vol 133 (21) ◽

pp. 4391-4391

Keyword(s):

Photoperiodic Flowering ◽

Spa Proteins

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Faculty Opinions recommendation of The Arabidopsis SPA1 gene is required for circadian clock function and photoperiodic flowering.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1001654.374751 ◽

2006 ◽

Author(s):

Xing Wang Deng

Keyword(s):

Circadian Clock ◽

Photoperiodic Flowering

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FLOWERING HTH1 is involved in CONSTANS-mediated flowering regulation in Arabidopsis

Applied Biological Chemistry ◽

10.1186/s13765-019-0465-x ◽

2019 ◽

Vol 62 (1) ◽

Author(s):

Soon Ae Sim ◽

Su Gyeong Woo ◽

Dae Yeon Hwang ◽

Jin-Hong Kim ◽

Seung Sik Lee ◽

...

Keyword(s):

Subcellular Location ◽

Day Length ◽

Interacting Protein ◽

Photoperiodic Flowering ◽

Family Protein ◽

Flowering Regulation ◽

Delayed Flowering ◽

The Right ◽

Two Hybrid ◽

Repression Domain

Abstract Flowering at the right time is essential for maximum reproductive fitness. In Arabidopsis thaliana, the CONSTANS (CO) protein facilitates the transition from the vegetative phase to the reproductive phase under long-day conditions. The formation of heterodimeric complexes between CO and DNA binding domain-containing transcription factors is important for the induction of day length-dependent flowering. Here, we report a myb-like helix turn helix (HTH) transcriptional regulator family protein as a new modulator of floral transition, which we have named FLOWERING HTH1 (FHTH1). We isolated FHTH1 as a CO-interacting protein by a yeast two-hybrid screen using an Arabidopsis transcription factor library. Our analysis showed that FHTH1 presented in the nucleus and the FHTH1-CO complex was formed in the same subcellular location. We also observed the expression of a FHTH1:GUS construct in the leaf vasculature, where CO exists. Transgenic plants overexpressing FHTH1 fused with the plant-specific repression domain SRDX showed a delayed flowering phenotype in long days, resembling the phenotype of the co mutant. Our results suggest that FHTH1 may contribute to CO-mediated photoperiodic flowering regulation.

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