Scuola Superiore Sant'Anna, Institute of Life Sciences, Pisa 56127, Italy.
Plant Cell Physiol. 2021 Nov 10;62(8):1251-1258. doi: 10.1093/pcp/pcab039.
Oxygen is essential for multicellular aerobic life due to its central role in energy metabolism. The availability of oxygen can drop below the level to sustain oxidative phosphorylation when plants are flooded, posing a severe threat to survival. However, under non-stressful conditions, the internal oxygen concentration of most plant tissue is not in equilibrium with the environment, which is attributed to cellular respiration and diffusion constrains imposed by O2 barriers and bulky tissue. This is exemplified by the observations of steep oxygen gradients in roots, fruits, tubers, anthers and meristems. To adapt to a varying availability of oxygen, plants sense O2 via the conditional proteolysis of transcriptional regulators. This mechanism acts to switch oxidative metabolism to anaerobic fermentation, but it was also shown to play a role in plant development and pathogen defense. To investigate how dynamic and spatial distribution of O2 impacts on these processes, accurate mapping of its concentration in plants is essential. Physical oxygen sensors have been employed for decades to profile internal oxygen concentrations in plants, while genetically encoded oxygen biosensors have only recently started to see use. Driven by the critical role of hypoxia in human pathology and development, several novel oxygen-sensing devices have also been characterized in cell lines and animal model organisms. This review aims to provide an overview of available oxygen biosensors and to discuss their potential application to image oxygen levels in plants.
氧气对于需氧的多细胞生物至关重要，因为它在能量代谢中起着核心作用。当植物被淹没时，氧气的供应可能会下降到无法维持氧化磷酸化的水平，这对生存构成了严重威胁。然而，在非胁迫条件下，大多数植物组织的内部氧气浓度与环境并不平衡，这归因于细胞呼吸和扩散受到 O2 屏障和庞大组织的限制。这可以通过观察到在根、果实、块茎、花药和分生组织中存在陡峭的氧气梯度来证明。为了适应氧气供应的变化，植物通过转录调节因子的条件性蛋白水解来感知 O2。这种机制作用是将氧化代谢切换为无氧发酵，但它也被证明在植物发育和病原体防御中发挥作用。为了研究氧气的动态和空间分布如何影响这些过程，精确绘制植物中氧气浓度的图谱是必不可少的。几十年来，物理氧气传感器一直被用于分析植物内部氧气浓度，而基因编码的氧气生物传感器直到最近才开始使用。由于缺氧在人类病理和发育中的关键作用，一些新型氧气感应装置也已在细胞系和动物模型生物中得到了描述。本综述旨在概述可用的氧气生物传感器，并讨论它们在植物中成像氧气水平的潜在应用。
