SummaryWood formation, which occurs mainly through secondary xylem development, is important not only for supplying raw material for the ‘ligno‐chemical’ industry but also for driving the storage of carbon. However, the complex mechanisms underlying the promotion of xylem formation remain to be elucidated. Here, we found that overexpression of Auxin‐Regulated Gene involved in Organ Size (ARGOS) in hybrid poplar 84 K (Populus alba × Populus tremula var. glandulosa) enlarged organ size. In particular, PagARGOS promoted secondary growth of stems with increased xylem formation. To gain further insight into how PagARGOS regulates xylem development, we further carried out yeast two‐hybrid screening and identified that the auxin transporter WALLS ARE THIN1 (WAT1) interacts with PagARGOS. Overexpression of PagARGOS up‐regulated WAT1, activating a downstream auxin response promoting cambial cell division and xylem differentiation for wood formation. Moreover, overexpressing PagARGOS caused not only higher wood yield but also lower lignin content compared with wild‐type controls. PagARGOS is therefore a potential candidate gene for engineering fast‐growing and low‐lignin trees with improved biomass production.

中文翻译：

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PagARGOS 促进杨树中低木质素木材的形成

摘要木材的形成主要通过次生木质部发育发生，不仅对于为“木质化学”工业供应原材料而且对于驱动碳储存也很重要。然而，促进木质部形成的复杂机制仍有待阐明。在这里，我们发现过度表达生长素调节基因涉及器官大小（阿尔戈斯) 杂交杨树 84 K (白杨 × 欧洲山杨变种腺体) 器官尺寸增大。尤其，帕格阿戈斯促进茎的二次生长，增加木质部形成。为了进一步了解如何帕格阿戈斯调控木质部发育，我们进一步进行了酵母双杂交筛选，发现生长素转运蛋白 WALLS ARE THIN1 (WAT1) 与 PagARGOS 相互作用。过度表达帕格阿戈斯上调的瓦特1，激活下游生长素反应，促进形成层细胞分裂和木质部分化，从而形成木材。此外，过度表达帕格阿戈斯与野生型对照相比，不仅导致更高的木材产量，而且导致更低的木质素含量。帕格阿戈斯因此，它是工程快速生长和低木质素树木的潜在候选基因，可提高生物量产量。