Zhang Shengkui, Li Can, Cui Baihui, Kou Wenhua, Feng Ping, Wang Xia
School of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, Shandong, China.
School of Architecture and Design, Chongqing College of Humanities, Science and Technology, Chongqing 401524, China.
Int J Biol Macromol. 2025 May;306(Pt 2):141656. doi: 10.1016/j.ijbiomac.2025.141656. Epub 2025 Mar 1.
Secondary wall, a critical component of wood, is influenced by multiple factors during its formation. The TCP family encodes plant-specific transcription factors (TFs) that play key roles in multiple aspects of plant development. In this study, we identified all TCP TFs in five poplar species and analyzed their evolutionary relationships, gene structures, tissue-specific expression patterns, and potential interactions with microRNAs. Additionally, we screened for TCP proteins associated with secondary wall development that are independent of miRNA regulation. Three candidate TFs were identified, with TCP23 showing high conservation across poplar species and the highest expression levels in the xylem of Populus trichocarpa and Populus wilsonii. The overexpression of TCP23 in poplar inhibited the expression of MYB TFs and structural genes involved in xylem biosynthesis, thereby reducing the lignin content within the stems. By contrast, CRISPR/Cas9-mediated knockout of TCP23 resulted in the opposite effect. Furthermore, we successfully identified WRKY15 as an interaction partner of TCP23 via a yeast two-hybrid library and demonstrated that TCP23 negatively regulates lignin synthesis and xylem development by enhancing the inhibitory function of WRKY15. Our study provides new insights into the transcriptional regulatory mechanisms underlying secondary wall formation.
次生壁是木材的关键组成部分，其形成过程受多种因素影响。TCP家族编码植物特有的转录因子（TFs），这些转录因子在植物发育的多个方面发挥关键作用。在本研究中，我们鉴定了五种杨树中的所有TCP转录因子，并分析了它们的进化关系、基因结构、组织特异性表达模式以及与微小RNA的潜在相互作用。此外，我们筛选了与次生壁发育相关且独立于miRNA调控的TCP蛋白。鉴定出三个候选转录因子，其中TCP23在杨树物种间具有高度保守性，在毛果杨和小叶杨的木质部中表达水平最高。在杨树中过表达TCP23会抑制参与木质部生物合成的MYB转录因子和结构基因的表达，从而降低茎中的木质素含量。相反，CRISPR/Cas9介导的TCP23基因敲除则产生相反的效果。此外，我们通过酵母双杂交文库成功鉴定出WRKY15是TCP23的相互作用伙伴，并证明TCP23通过增强WRKY15的抑制功能对木质素合成和木质部发育起负调控作用。我们的研究为次生壁形成的转录调控机制提供了新的见解。
