The Phytochrome-Interacting VASCULAR PLANT ONE-ZINC FINGER1 and VOZ2 Redundantly Regulate Flowering in Arabidopsis

• Published in: The Plant cell 2012-08, Vol.24 (8), p.3248-3263
• Main Authors: Yasui, Yukiko, Mukougawa, Keiko, Uemoto, Mitsuhiro, Yokofuji, Akira, Suzuri, Ryota, Nishitani, Aiko, Kohchi, Takayuki
• Format: Article
• Language: English
• Subjects: Antibodies; Arabidopsis; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis - physiology; Arabidopsis - radiation effects; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Cell Nucleus - genetics; Cell Nucleus - metabolism; Cytoplasm; Cytoplasm - metabolism; Flowering; Flowers - genetics; Flowers - metabolism; Flowers - physiology; Flowers - radiation effects; Gene expression regulation; Gene Expression Regulation, Plant; Genes, Plant; Green Fluorescent Proteins - metabolism; Light; Mutation; Phenotype; Phenotypes; phytochrome; Phytochrome B - genetics; Phytochrome B - metabolism; Plant cells; Plant Leaves - genetics; Plant Leaves - metabolism; Plant Leaves - physiology; Plant Vascular Bundle - genetics; Plant Vascular Bundle - metabolism; Plants; Plants, Genetically Modified - genetics; Plants, Genetically Modified - metabolism; Plants, Genetically Modified - physiology; Protein Interaction Mapping; Protein Stability; Protein Transport; Proteins; Proteolysis; Seedlings; Signal Transduction; Transcription Factors - genetics; Transcription Factors - metabolism; Vascular bundles; Zinc Fingers
• ISSN: 1040-4651; 1532-298X
• DOI: 10.1105/tpc.112.101915

The timing of the transition to flowering in plants is regulated by various environmental factors, including daylength and light quality. Although the red/far-red photoreceptor phytochrome B (phyB) represses flowering by indirectly regulating the expression of a key flowering regulator, FLOWERING LOCUS T [FT), the mechanism of phyB signaling for flowering is largely unknown. Here, we identified two Arabidopsis thaliana genes, VASCULAR PLANT ONE-ZINC FINGER1 (VOZ1) and VOZ2, which are highly conserved throughout land plant evolution, as phyB-interacting factors. voz1 voz2 double mutants, but neither single mutant, showed a late-flowering phenotype under long-day conditions, which indicated that VOZ1 and VOZ2 redundantly promote flowering. voz1 voz2 mutations suppressed the early-flowering phenotype of the phyB mutant, and FT expression was repressed in the voz1 voz2 mutant. Green fluorescent protein-VOZ2 signal was observed in the cytoplasm, and interaction of VOZ proteins with phyB was indicated to occur in the cytoplasm under far-red light. However, VOZ2 protein modified to localize constitutively in the nucleus promoted flowering. In addition, the stability of VOZ2 proteins in the nucleus was modulated by light quality in a phytochrome-dependent manner. We propose that partial translocation of VOZ proteins from the cytoplasm to the nucleus mediates the initial step of the phyB signal transduction pathway that regulates flowering.