Yue Jing, Yang Linxi, Xu Shouling, Wei Mingke, Li Quanzi
State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing, China.
National Key Laboratory of Development and Utilization of Forest Food Resources, Zhejiang Key Laboratory of Forest Genetics and Breeding, College of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, China.
Plant Cell Environ. 2025 Nov;48(11):8177-8189. doi: 10.1111/pce.70118. Epub 2025 Aug 13.
Secondary cell wall (SCW) synthesis is a critical process of wood formation. Extensive studies have identified NAC and MYB transcription factors as key regulators of SCW thickening. Currently, no studies reveal the involvement of BTB/POZ proteins during wood formation. In this study, we investigated the role of a BTB/POZ protein during wood formation in Populus alba × Populus glandulosa. PagBTB74 overexpression (PagBTB74-OE) and dominant repression (PagBTB74-SRDX) transgenic plants exhibited narrowed xylem and thinner SCWs of xylem cells. Conversely, RNAi silencing (PagBTB74-RNAi) transgenic plants displayed opposite phenotypes with widened xylem and thickened walls. Integrated chromatin immunoprecipitation (ChIP), RNA-seq and yeast one-hybridisation (Y1H) analyses identified PagVDN6-C1, PagCesA7 and PagXTH4 as direct targets of PagBTB74. RNA-seq and effector-reporter assays showed that these three genes were downregulated by PagBTB74, consisting with the result that PagBTB74 had transcriptional repression activities. Our study represents the first report of a BTB transcription factor as a negative regulator of SCW biosynthesis during wood formation, and this regulation may occur through direct repression of the key genes of SCW biosynthesis, including PagVND6-C1, PagCesA7 and PagXTH4.
次生细胞壁（SCW）合成是木材形成的关键过程。大量研究已确定NAC和MYB转录因子是SCW增厚的关键调节因子。目前，尚无研究揭示BTB/POZ蛋白在木材形成过程中的作用。在本研究中，我们调查了一种BTB/POZ蛋白在银白杨×腺毛杨木材形成过程中的作用。PagBTB74过表达（PagBTB74-OE）和显性抑制（PagBTB74-SRDX）转基因植株表现出木质部变窄和木质部细胞的SCW变薄。相反，RNA干扰沉默（PagBTB74-RNAi）转基因植株表现出相反的表型，木质部变宽且细胞壁增厚。综合染色质免疫沉淀（ChIP）、RNA测序和酵母单杂交（Y1H）分析确定PagVDN6-C1、PagCesA7和PagXTH4是PagBTB74的直接靶标。RNA测序和效应物-报告基因检测表明，这三个基因被PagBTB74下调，这与PagBTB74具有转录抑制活性的结果一致。我们的研究首次报道了一种BTB转录因子作为木材形成过程中SCW生物合成的负调节因子，这种调节可能是通过直接抑制SCW生物合成的关键基因，包括PagVND6-C1、PagCesA7和PagXTH4来实现的。
