Renziehausen Tilo, Chaudhury Rim, Hartman Sjon, Mustroph Angelika, Schmidt-Schippers Romy R
Plant Biotechnology, Faculty of Biology, University of Bielefeld, 33615 Bielefeld, Germany.
Center for Biotechnology, University of Bielefeld, 33615 Bielefeld, Germany.
Plant Physiol. 2024 Dec 23;197(1). doi: 10.1093/plphys/kiae596.
Oxygen deficiency (hypoxia) occurs naturally in many developing plant tissues but can become a major threat during acute flooding stress. Consequently, plants as aerobic organisms must rapidly acclimate to hypoxia and the associated energy crisis to ensure cellular and ultimately organismal survival. In plants, oxygen sensing is tightly linked with oxygen-controlled protein stability of group VII ETHYLENE-RESPONSE FACTORs (ERFVII), which, when stabilized under hypoxia, act as key transcriptional regulators of hypoxia-responsive genes (HRGs). Multiple signaling pathways feed into hypoxia signaling to fine-tune cellular decision-making under stress. First, ATP shortage upon hypoxia directly affects the energy status and adjusts anaerobic metabolism. Secondly, altered redox homeostasis leads to reactive oxygen and nitrogen species (ROS and RNS) accumulation, evoking signaling and oxidative stress acclimation. Finally, the phytohormone ethylene promotes hypoxia signaling to improve acute stress acclimation, while hypoxia signaling in turn can alter ethylene, auxin, abscisic acid, salicylic acid, and jasmonate signaling to guide development and stress responses. In this Update, we summarize the current knowledge on how energy, redox, and hormone signaling pathways are induced under hypoxia and subsequently integrated at the molecular level to ensure stress-tailored cellular responses. We show that some HRGs are responsive to changes in redox, energy, and ethylene independently of the oxygen status, and we propose an updated HRG list that is more representative for hypoxia marker gene expression. We discuss the synergistic effects of hypoxia, energy, redox, and hormone signaling and their phenotypic consequences in the context of both environmental and developmental hypoxia.
氧缺乏（缺氧）在许多正在发育的植物组织中自然发生，但在急性淹水胁迫期间可能成为主要威胁。因此，作为需氧生物的植物必须迅速适应缺氧及相关的能量危机，以确保细胞乃至整个生物体的存活。在植物中，氧感知与VII类乙烯反应因子（ERFVII）的氧控蛋白稳定性紧密相关，ERFVII在缺氧条件下稳定时，作为缺氧响应基因（HRG）的关键转录调节因子发挥作用。多种信号通路汇入缺氧信号，以在胁迫下微调细胞决策。首先，缺氧时ATP短缺直接影响能量状态并调节无氧代谢。其次，氧化还原稳态的改变导致活性氧和氮物种（ROS和RNS）积累，引发信号传导和氧化应激适应。最后，植物激素乙烯促进缺氧信号传导以改善急性胁迫适应，而缺氧信号传导反过来又可改变乙烯、生长素、脱落酸、水杨酸和茉莉酸信号传导，以指导发育和胁迫反应。在本综述中，我们总结了关于能量、氧化还原和激素信号通路如何在缺氧条件下被诱导以及随后在分子水平整合以确保针对胁迫的细胞反应的现有知识。我们表明，一些HRG对氧化还原、能量和乙烯的变化有反应，而与氧状态无关，并且我们提出了一份更新的HRG清单，该清单更能代表缺氧标记基因的表达。我们讨论了缺氧、能量、氧化还原和激素信号传导的协同效应及其在环境和发育性缺氧背景下的表型后果。
