Fan Erqin, Liu Caixia, Liu Yaru, Fu Pengyue, Liu Yuhang, Yang Chuanping, Wang Junhui, Qu Guanzheng
State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin, 150040, China.
State Key Laboratory of Utilization of Woody Oil Resource, Central South University of Forestry and Technology, Changsha, 410004, China.
Plant Cell Rep. 2025 Aug 22;44(9):201. doi: 10.1007/s00299-025-03588-6.
PagC3H3, encoding a p-coumarate 3-hydroxylase, catalyzes a critical step in lignin biosynthesis and confers enhanced insect resistance in poplar. Its overexpression increases lignin deposition, enhancing physical barrier formation against arthropod herbivory (e.g., reduced gypsy moth larval consumption). This provides a genetic engineering strategy for improving wood properties and biotic stress resilience. Lignin, a complex phenolic polymer crucial for structural integrity and biotic stress resistance in poplar, critically influences wood processing efficiency and ecological resilience. Targeted genetic manipulation of key enzymes like p-coumarate 3-hydroxylase (C3H) remains underexplored in commercial hybrids. In this study, we investigated the role of PagC3H3 in lignin biosynthesis in the hybrid poplar Populus alba × Populus glandulosa (clone 84K). Through the overexpression and suppression of PagC3H3 in poplar 84K, we observed that elevated PagC3H3 expression significantly increases lignin content and enhances resistance to insect pests by enhancing physical barrier formation against arthropod herbivory, whereas RNAi-suppression lines exhibited reduced lignin and compromised growth. RNA-seq results showed that the expression of genes related to secondary cell wall components changed significantly, and 985 differentially expressed genes were co-regulated in the two transgenic lines, involving key transcription factors and structural genes for lignin synthesis and cell wall development. The results revealed the key role of PagC3H3 in regulating lignin synthesis and cell wall development, and provided a new strategy for improving the wood properties and insect resistance of trees. This study not only improves the understanding of the molecular mechanism of lignin synthesis, but also provides a theoretical basis for the genetic improvement of poplar.
PagC3H3编码对香豆酸3-羟化酶，催化木质素生物合成中的关键步骤，并赋予杨树增强的抗虫性。其过表达增加了木质素沉积，增强了针对节肢动物食草作用的物理屏障形成（例如，减少舞毒蛾幼虫的取食量）。这为改善木材性质和生物胁迫恢复力提供了一种基因工程策略。木质素是一种复杂的酚类聚合物，对杨树的结构完整性和生物胁迫抗性至关重要，严重影响木材加工效率和生态恢复力。在商业杂交品种中，对香豆酸3-羟化酶（C3H）等关键酶的靶向基因操作仍未得到充分探索。在本研究中，我们调查了PagC3H3在杂种杨树银白杨×腺毛杨（84K无性系）木质素生物合成中的作用。通过在84K杨树中过表达和抑制PagC3H3，我们观察到PagC3H3表达升高显著增加了木质素含量，并通过增强针对节肢动物食草作用的物理屏障形成来增强对害虫的抗性，而RNA干扰抑制系的木质素减少且生长受损。RNA测序结果表明，与次生细胞壁成分相关的基因表达发生了显著变化，并且在两个转基因系中共调控了985个差异表达基因，涉及木质素合成和细胞壁发育的关键转录因子和结构基因。结果揭示了PagC3H3在调节木质素合成和细胞壁发育中的关键作用，并为改善树木的木材性质和抗虫性提供了新策略。本研究不仅增进了对木质素合成分子机制的理解，也为杨树的遗传改良提供了理论依据。
