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Journal of Integrative Agriculture  2026, Vol. 25 Issue (11): 4649-4659    DOI: 10.1016/j.jia.2026.03.028
Horticulture Advanced Online Publication | Current Issue | Archive | Adv Search |
The PbTCP2–PbTCP4 protein complex promotes pear flowering by suppressing transcription of the flowering-repressor gene PbSVP

Hongjuan Zhang*, Jingjing Cheng*, Kaile Liu, Hongbo Xia, Yutong Wang, Zesheng Wang, Jingjing Miao, Guangya Sha, Rui Zhai, Chengquan Yang, Zhigang Wang, Lingfei Xu#

College of Horticulture, Northwest A&F University, Yangling 712100, China

 Highlights 
● Both PbTCP2 and PbTCP4 regulate pear flowering.
● PbTCP2 blocks transcription of the flowering-repressor gene PbSVP (SHORT VEGETATIVE PHASE) by directly binding to its promoter.
● Transcriptional repression of PbSVP is enhanced when PbTCP2 forms a complex with PbTCP4.
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摘要  

TEOSINTE BRANCHED 1/CYCLOIDEA/PROLIFERATING CELL FACTOR(TCP)家族是植物特有的转录因子家族,调控开花转变等众多生长发育过程。然而,TCP 基因在梨开花调控中的功能尚未明确。本研究鉴定到一个与梨开花相关的转录因子 PbTCP2,其编码产物为典型核定位蛋白,且无自激活活性。拟南芥异源过表达实验证实,PbTCP2 具有促进开花的生物学功能:与野生型相比,PbTCP2 过表达株系中开花促进因子转录水平显著升高,而开花抑制因子 PbSVP(SHORT VEGETATIVE PHASE)等转录水平显著下调。酵母单杂交(Y1H)和电泳迁移率变动分析(EMSA)证实,PbTCP2 蛋白可直接结合 PbSVP 启动子;双荧光素酶报告实验(LUC)进一步验证其对PbSVP的转录抑制活性。此外,酵母双杂交(Y2H)、双分子荧光互补(BiFC)及pull-down实验表明,PbTCP4 与 PbTCP2 存在物理相互作用;且 PbTCP4 通过与 PbTCP2 形成复合体,可协同增强后者对 PbSVP 的转录抑制效应,该结论得到 LUC 和 GUS 染色实验的佐证。同时,PbTCP4 拟南芥过表达株系也表现出早花表型。综上,本研究揭示了梨中 TCP4-TCP2 复合体通过调控 PbSVP 转录进而调控开花的分子机制,为解析多年生作物开花调控机理提供了新视角。



Abstract  

Members of the TEOSINTE BRANCHED 1/CYCLOIDEA/PROLIFERATING CELL FACTOR (TCP) family are plant-specific transcription factors regulating numerous growth and development processes, including the floral transition.  However, the roles of TCP genes in regulating the flowering of pear remain unknown.  Here, we identified PbTCP2 as a transcription factor associated with flowering.  PbTCP2 was identified as a typical nucleus-located transcription factor without self-activation activity.  We verified the biological function of PbTCP2 in accelerating floral transition via heterologous overexpression in Arabidopsis thaliana.  Compared with wild-type Arabidopsis lines, PbTCP2-overexpressing plants displayed elevated transcript levels of flowering activators, whereas transcript levels of flowering repressors, including PbSVP (SHORT VEGETATIVE PHASE), were significantly decreased.  Yeast one-hybrid and electrophoretic mobility shift assays indicated that PbTCP2 protein directly binds to the promoter of PbSVP.  The transcriptional repression activity of PbTCP2 on PbSVP was further confirmed by dual-luciferase assays.  We further showed that PbTCP4 interacts with PbTCP2, as evidenced by yeast two-hybrid, bimolecular fluorescence complementation, and pull-down assays.  Notably, forming a complex with PbTCP2, PbTCP4 synergistically enhanced this repression, a conclusion supported by dual-luciferase and GUS staining assays.  Overexpression of PbTCP4 also promoted flowering in Arabidopsis.  Collectively, these findings confirm a PbSVP-controlled flowering mechanism regulated by the PbTCP4–PbTCP2 complex in pear, shedding light on the molecular mechanisms underlying flowering regulation in perennial crops.

Keywords:  PbTCP2       PbTCP4       flowering time       PbSVP       pear   
Received: 23 May 2025   Accepted: 04 February 2026 Online: 11 March 2026  
Fund: 

This research was funded by the China Agriculture Research System (CARS 28), and Weinan Experimental Station Foundation of Northwest A&F University, China (WNXNZX-4).

About author:  Hongjuan Zhang, E-mail: Zhanghj0625@163.com; Jingjing Cheng, E-mail: JJcheng@nwafu.edu.cn; #Correspondence Lingfei Xu, Tel: +86-29-87081023, E-mail: lingfxu2013@sina.com * These authors contributed equally to this study.

Cite this article: 

Hongjuan Zhang, Jingjing Cheng, Kaile Liu, Hongbo Xia, Yutong Wang, Zesheng Wang, Jingjing Miao, Guangya Sha, Rui Zhai, Chengquan Yang, Zhigang Wang, Lingfei Xu. 2026. The PbTCP2–PbTCP4 protein complex promotes pear flowering by suppressing transcription of the flowering-repressor gene PbSVP. Journal of Integrative Agriculture, 25(11): 4649-4659.

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