Liu Shuai, Fu Xiaokang, Wang Yue, Du Xuelian, Luo Lianjia, Chen Dong, Liu Chunzhao, Hu Jian, Fa Changjian, Wu Rongling, Li Laigeng, Luo Keming, Xu Changzheng
Chongqing Key Laboratory of Tree Germplasm Innovation and Utilization, Integrative Science Center of Germplasm Creation, School of Life Sciences, Southwest University, Chongqing, China.
Key Laboratory of Eco-environments of Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China.
Nat Plants. 2025 Mar;11(3):580-594. doi: 10.1038/s41477-025-01931-z. Epub 2025 Mar 19.
Auxin, as a vital phytohormone, is enriched in the vascular cambium, playing a crucial role in regulating wood formation in trees. While auxin's influence on cambial stem cells is well established, the molecular mechanisms underlying the auxin-directed development of cambial derivatives, such as wood fibres, remain elusive in forest trees. Here we identified a transcription factor, AINTEGUMENTA-like 5 (AIL5)/PLETHORA 5 (PLT5) from Populus tomentosa, that is specifically activated by auxin signalling within the vascular cambium. PLT5 regulated both cell expansion and cell wall thickening in wood fibres. Genetic analysis demonstrated that PLT5 is essential for mediating the action of auxin signalling on wood fibre development. Remarkably, PLT5 specifically inhibits the onset of fibre cell wall thickening by directly repressing SECONDARY WALL-ASSOCIATED NAC DOMAIN 1 (SND1) genes. Our findings reveal a sophisticated auxin-PLT5 signalling pathway that finely tunes the development of wood fibres by controlling cell wall thickening.
生长素作为一种重要的植物激素，在维管形成层中富集，对树木木质部形成的调控起着关键作用。虽然生长素对形成层干细胞的影响已得到充分证实，但在林木中，生长素导向形成层衍生物（如木纤维）发育的分子机制仍不清楚。在此，我们从毛白杨中鉴定出一种转录因子，即类珠被绒毡层1 5（AIL5）/多胚形成5（PLT5），它在维管形成层中被生长素信号特异性激活。PLT5调控木纤维中的细胞扩张和细胞壁加厚。遗传分析表明，PLT5对于介导生长素信号对木纤维发育的作用至关重要。值得注意的是，PLT5通过直接抑制次生壁相关NAC结构域1（SND1）基因，特异性地抑制纤维细胞壁加厚的起始。我们的研究结果揭示了一条复杂的生长素-PLT5信号通路，该通路通过控制细胞壁加厚来精细调节木纤维的发育。
