Tyrosine decarboxylase (TyDC) converts tyrosine to tyramine and plays a crucial role in secondary metabolite reactions, development, and stress responses in plants. Currently, the biological role of TyDC proteins from trees is unknown. This study provided evidence showing that poplar functions in wood development and drought stress response. is preferentially expressed in wood-forming cells in stems. Overexpression of in poplars under the control of a xylem-specific promoter resulted in an increase in the ratio of xylem to phloem width, vessel cell area, and lignin accumulation in the stems. Biochemical assays revealed that PaTyDC4 is a component of the PaC3H17-PaMYB199 module-mediated pathway. In poplar stems, expression was directly suppressed by PaMYB199, which was attenuated by the interaction between PaC3H17 and PaMYB199. In addition, overexpression lines showed stronger drought tolerance than the wild-type lines, with higher photosynthetic capacity and lower levels of HO. These results indicate that PaTyDC4 promotes xylem differentiation and lignin deposition during secondary growth and confers drought tolerance. Our findings may be useful for the genetic modification of biomass and drought resistance in trees.

中文翻译：

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PaTyDC4的木材形成组织特异性表达促进次生生长过程中的木质部分化和木质素沉积，并赋予杨树耐旱性

酪氨酸脱羧酶 (TyDC) 将酪氨酸转化为酪胺，在植物的次生代谢反应、发育和胁迫反应中发挥着至关重要的作用。目前，来自树木的 TyDC 蛋白的生物学作用尚不清楚。这项研究提供的证据表明杨树在木材发育和干旱胁迫反应中发挥作用。优先在茎中的木材形成细胞中表达。在木质部特异性启动子的控制下，杨树中 的过度表达导致木质部与韧皮部宽度的比率、导管细胞面积和茎中木质素积累的增加。生化检测显示 PaTyDC4 是 PaC3H17-PaMYB199 模块介导途径的一个组成部分。在杨树茎中，PaMYB199 直接抑制表达，PaC3H17 和 PaMYB199 之间的相互作用减弱了表达。此外，过表达株系比野生型株系表现出更强的耐旱性，具有更高的光合能力和更低的H2O水平。这些结果表明PaTyDC4在次生生长过程中促进木质部分化和木质素沉积并赋予干旱耐受性。我们的发现可能对树木生物量和抗旱性的基因改造有用。