Institute of Plant and Microbial Biology; Academia Sinica; Taipei, Taiwan; Molecular and Biological Agricultural Sciences; Taiwan International Graduate Program; National Chung Hsing University-Academia Sinica; Taipei, Taiwan; Graduate Institute of Biotechnology; National Chung-Hsing University; Taichung, Taiwan.
Plant Signal Behav. 2013 May;8(5):e24066. doi: 10.4161/psb.24066. Epub 2013 Mar 1.
Reactive oxygen species (ROS) have been shown to play key roles in cellular decision making and signal integration in multicellular organisms. In roots, ROS levels are managed by the action of peroxidases and NAPDH oxidases, resulting in a distinct spatial distribution of hydrogen peroxide (H₂O₂) and superoxide (O₂(-)) that is critical for the balance between cell proliferation and differentiation. In addition, ROS is required for the determination of the cell shape of root hairs. Mutations in the Mediator subunit MED25/PFT1 result in compromised root hair development, due to altered expression of a suite of H₂O₂-producing class III peroxidases. pft1-1 mutants form shorter root hairs than wild-type plants. Analysis of pft1-1 cross-sections revealed that also root hair initiation is compromised, probably by impeding local cell wall loosening. It is suggested that ROS homeostasis is critical throughout the development of root hairs, controlling various processes via PFT1-regulated transcription of genes encoding redox-active enzymes.
活性氧（ROS）已被证明在多细胞生物的细胞决策和信号整合中发挥关键作用。在根中，过氧化物酶和 NADPH 氧化酶的作用管理 ROS 水平，导致过氧化氢（H₂O₂）和超氧阴离子（O₂(-)）的独特空间分布，这对于细胞增殖和分化之间的平衡至关重要。此外，ROS 是确定根毛细胞形状所必需的。由于一系列产生 H₂O₂的 III 类过氧化物酶表达改变，Mediator 亚基 MED25/PFT1 突变导致根毛发育受损。pft1-1 突变体形成的根毛比野生型植物短。对 pft1-1 横切面的分析表明，根毛起始也受到损害，可能是通过阻碍局部细胞壁松解。因此，ROS 动态平衡在根毛发育的整个过程中至关重要，通过 PFT1 调节编码氧化还原活性酶的基因的转录来控制各种过程。
