VASCULAR PLANT ONE-ZINC FINGER1 (VOZ1) and VOZ2 interact with CONSTANS and promote photoperiodic flowering transition 

First author: Sushil Kumar; Affiliations: Indian Institute of Science (印度科学研究所): Karnataka, India

Corresponding author: Utpal Nath

In plants, endogenous and environmental signals such as light control the timing of the transition to flowering. Two phytochrome B-interacting transcription factors (光敏色素B互作转录因子), VASCULAR PLANT ONE-ZINC FINGER1 (VOZ1) and VOZ2 redundantly promote flowering in Arabidopsis thaliana. In the voz1 voz2 mutant the expression of FLOWERING LOCUS C (FLC) was up-regulated and that of FLOWERING LOCUS T (FT) was down-regulated, which was proposed to be the cause of late flowering in voz1 voz2. However, the detailed mechanism by which the VOZ genes promote flowering is not well understood. Here, we show that neither the reduced FT-expression nor the late-flowering phenotype of voz1 voz2 is suppressed in the voz1 voz2 flc triple mutant. Genetic interaction experiments between voz1 voz2 and constans-2 (co-2) mutants reveal that the VOZs and CO work in the same genetic pathway. Using in vitro pull-down, electrophoretic mobility shift assays (凝胶电泳迁移率变动试验) and bimolecular fluorescence complementation assays (双分子荧光互补试验), we show that VOZ1 and VOZ2 interact with CO. The voz1 voz2 35S::CO:YFP plants show suppression of the early-flowering phenotype induced by CO-overexpression, suggesting that CO requires VOZ for induction of flowering. Determination of the VOZ consensus binding site followed by genome-wide sequence analysis failed to identify any VOZ-binding sites near known flowering-time genes. Together, these results indicate that the VOZ genes regulate flowering primarily through the photoperiod pathway (光周期途径), independent of FLC, and suggest that VOZs modulate CO function to promote flowering.

在植物中，内源和环境的信号如光照调控植物向成花的转变。两个光敏色素B互作转录因子VOZ1和VOZ2促进拟南芥的开花，但功能冗余。在voz1 voz2双突变体中，FLC基因的表达上调，而FT基因的表达下调，最终导致voz1 voz2双突变体的晚花表型。然而，VOZ基因通过什么机制促进了开花仍然不清楚。本文的研究显示无论是FT基因表达的降低亦或是voz1 voz2双突变体的晚花表型在voz1 voz2 flc三突变体中均未被抑制。voz1 voz2和co-2突变体的遗传互作试验显示VOZs和CO基因处于同一个遗传通路上。利用离体的pull-down、凝胶电泳迁移率变动试验EMSA和双分子荧光互补试验BiFC，作者表明VOZ1和VOZ2与CO互作。voz1 voz2 35S::CO:YFP突变体植株中显示CO的过表达会诱导早花表型，表明CO需要VOZ一起诱导开花。作者进一步鉴定了VOZ的结合位点序列，接着全基因的序列分析显示并未在任何已知的开花时间调控相关基因附近鉴定到可能的VOZ的结合位点。综上，本研究显示VOZ基因主要通过光周期途径调控周开花，独立于FLC基因，显示VOZs通过调控CO的功能来促进开花。

通讯：Utpal Nath (http://bio.iisc.ac.in/?q=faculty/utpal-nath)

研究方向：利用拟南芥为模式植物研究植物的生长和发育，包括叶片表面曲率的控制、叶片生长的极性分化、CIN/TCP4靶标的鉴定、叶边缘结构调控和腺毛发育的控制等。

doi: https://doi.org/10.1104/pp.17.01562

Journal: Plant Physiology

First Published date: 05 March, 2018

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