Xu Le, Liu Huaqiong, Mittler Ron, Shabala Sergey
MARA Key Laboratory of Sustainable Crop Production in the Middle Reaches of the Yangtze River (Co-construction by Ministry and Province), College of Agriculture, Engineering Research Centre of Ecology and Agricultural Use of Wetland, Ministry of Education, Yangtze University, Jingzhou, 434025China.
Division of Plant Science and Technology, College of Agriculture Food and Natural Resources, University of Missouri, Columbia, MO 65201, USA.
J Exp Bot. 2025 Apr 9;76(6):1524-1533. doi: 10.1093/jxb/erae524.
During their lifespan, plants are often exposed to a broad range of stresses that change their redox balance and lead to accumulation of reactive oxygen species (ROS). The traditional view is that this comes with negative consequences to cells structural integrity and metabolism and, to prevent this, plants evolved a complex and well-coordinated antioxidant defence system that relies on the operation of a range of enzymatic and non-enzymatic antioxidants (AO). Due to the simplicity of measuring their activity, and in light of the persistent dogma that stress-induced ROS accumulation is detrimental for plants, it is not surprising that enzymatic AOs have often been advocated as suitable proxies for stress tolerance as well as potential targets for improving tolerance traits. However, there are a growing number of reports showing either no changes or even down-regulation of AO systems in stressed plants. Moreover, ROS are recognized now as important second messengers operating in both local and systemic signalling, synergistically interacting with the primary stressor, to regulate gene expression needed for optimal acclimatization. This work critically assesses the suitability of using enzymatic AOs as a proxy for stress tolerance or as a target for crop genetic improvement. It is concluded that constitutively higher AO activity may interfere with stress-induced ROS signalling and be a disadvantage for plant stress tolerance.
在其生命周期中，植物常常会受到多种胁迫，这些胁迫会改变其氧化还原平衡并导致活性氧（ROS）的积累。传统观点认为，这会对细胞的结构完整性和代谢产生负面影响，为防止这种情况，植物进化出了一个复杂且协调良好的抗氧化防御系统，该系统依赖于一系列酶促和非酶促抗氧化剂（AO）的作用。由于测量它们活性的方法简单，并且鉴于应激诱导的ROS积累对植物有害这一长期存在的观念，酶促AO常常被认为是适合作为胁迫耐受性的指标以及改善耐受性性状的潜在靶点，这并不奇怪。然而，越来越多的报告显示，在受胁迫的植物中，AO系统要么没有变化，甚至下调。此外，现在ROS被认为是在局部和系统信号传导中起重要作用的第二信使，与主要胁迫源协同相互作用，以调节最佳适应所需的基因表达。这项工作批判性地评估了使用酶促AO作为胁迫耐受性指标或作为作物遗传改良靶点的适用性。得出的结论是，持续较高的AO活性可能会干扰应激诱导的ROS信号传导，对植物的胁迫耐受性不利。
