CONSTANS–FKBP12 interaction contributes to modulation of photoperiodic flowering in Arabidopsis

First author: Gloria Serrano‐Bueno; Affiliations: CSIC-Universidad de Sevilla (高等科学研究理事会-塞维利亚大学): Sevilla, Spain

Corresponding author: Federico Valverde

Flowering time is a key process in plant development. Photoperiodic signals play a crucial role in the floral transition in Arabidopsis thaliana, and the protein CONSTANS (CO) has a central regulatory function that is tightly regulated at the transcriptional and post‐translational levels. The stability of CO protein depends on a light‐driven proteasome process that optimizes its accumulation in the evening to promote the production of the florigen FLOWERING LOCUS T (FT) and induce seasonal flowering. To further investigate the post‐translational regulation of CO protein we have dissected its interactome network employing in vivo and in vitro assays and molecular genetics approaches. The immunophilin FKBP12 has been identified in Arabidopsis as a CO interactor that regulates its accumulation and activity. FKBP12 and CO interact through the CCT domain, affecting the stability and function of CO. fkbp12 insertion mutants show a delay in flowering time, while FKBP12 overexpression accelerates flowering, and these phenotypes can be directly related to a change in accumulation of FT protein. The interaction is conserved between the Chlamydomonas algal orthologs CrCO–CrFKBP12, revealing an ancient regulatory step in photoperiod regulation of plant development.

开花时间是植物发育的关键过程。光周期信号途径在拟南芥的成花转变过程中起到非常关键的作用，而CONSTANS（CO）蛋白是核心调控蛋白，其在转录和翻译后水平上受到严格的调节。CO蛋白的稳定性取决于光驱动的蛋白酶体过程，该过程可最大化CO在晚上的积累，从而促进开花基因FLOWERING LOCUS T（FT）的产生，诱导季节性开花。为了进一步研究CO蛋白的翻译后调控，作者使用体内和体外试验以及分子遗传学方法剖析了其相互作用组网络。在拟南芥中，免疫亲和蛋白FKBP12是CO蛋白的相互作用因子，能够调控CO的积累和活性。 FKBP12和CO通过CCT结构域互作，从而影响CO的稳定性和功能。fkbp12插入突变会导致开花时间延迟，而FKBP12过表达则加速开花，这些表型可能与FT蛋白积累的变化直接相关。在衣藻中同样存在保守的CrCO–CrFKBP12互作，说明植物发育的光周期调控是一个很古老的分子机制。

通讯：Federico Valverde (https://www.ibvf.us-csic.es/federico)

研究方向：植物发育和代谢的分子基础。 

doi: https://doi.org/10.1111/tpj.14590

Journal: the plant journal

First Published: October 29, 2019