Department of Biology, Lund University, Lund, Sweden.
Plant Physiol. 2021 May 27;186(1):36-52. doi: 10.1093/plphys/kiab101.
Plant mitochondria are indispensable for plant metabolism and are tightly integrated into cellular homeostasis. This review provides an update on the latest research concerning the organization and operation of plant mitochondrial redox systems, and how they affect cellular metabolism and signaling, plant development, and stress responses. New insights into the organization and operation of mitochondrial energy systems such as the tricarboxylic acid cycle and mitochondrial electron transport chain (mtETC) are discussed. The mtETC produces reactive oxygen and nitrogen species, which can act as signals or lead to cellular damage, and are thus efficiently removed by mitochondrial antioxidant systems, including Mn-superoxide dismutase, ascorbate-glutathione cycle, and thioredoxin-dependent peroxidases. Plant mitochondria are tightly connected with photosynthesis, photorespiration, and cytosolic metabolism, thereby providing redox-balancing. Mitochondrial proteins are targets of extensive post-translational modifications, but their functional significance and how they are added or removed remains unclear. To operate in sync with the whole cell, mitochondria can communicate their functional status via mitochondrial retrograde signaling to change nuclear gene expression, and several recent breakthroughs here are discussed. At a whole organism level, plant mitochondria thus play crucial roles from the first minutes after seed imbibition, supporting meristem activity, growth, and fertility, until senescence of darkened and aged tissue. Finally, plant mitochondria are tightly integrated with cellular and organismal responses to environmental challenges such as drought, salinity, heat, and submergence, but also threats posed by pathogens. Both the major recent advances and outstanding questions are reviewed, which may help future research efforts on plant mitochondria.
植物线粒体对于植物代谢是不可或缺的，并且与细胞内稳态紧密结合。这篇综述提供了关于植物线粒体氧化还原系统的最新研究进展的更新，包括它们如何影响细胞代谢和信号转导、植物发育和应激反应。讨论了线粒体能量系统（如三羧酸循环和线粒体电子传递链（mtETC））的组织和运作的新见解。mtETC 会产生活性氧和氮物种，它们可以作为信号或导致细胞损伤，因此被线粒体抗氧化系统（包括 Mn-超氧化物歧化酶、抗坏血酸-谷胱甘肽循环和硫氧还蛋白依赖性过氧化物酶）有效清除。植物线粒体与光合作用、光呼吸和细胞质代谢紧密相连，从而提供氧化还原平衡。线粒体蛋白是广泛翻译后修饰的靶标，但它们的功能意义以及如何添加或去除仍不清楚。为了与整个细胞同步运行，线粒体可以通过线粒体逆行信号传递来改变核基因表达，从而传递其功能状态，这里讨论了几个最近的突破。在整个生物体水平上，植物线粒体从种子吸水后的最初几分钟开始就发挥着至关重要的作用，支持分生组织的活性、生长和育性，直到黑暗和老化组织的衰老。最后，植物线粒体与细胞和生物体对环境挑战（如干旱、盐度、热和淹没）的反应以及病原体的威胁紧密结合。综述了最近的主要进展和悬而未决的问题，这可能有助于未来对植物线粒体的研究工作。
