Biochimie et Physiologie Moléculaire des Plantes, Unité Mixte de Recherche 5004, CNRS/INRA/Montpellier SupAgro/Université de Montpellier, Montpellier, France.
Physiol Rev. 2015 Oct;95(4):1321-58. doi: 10.1152/physrev.00008.2015.
Aquaporins are membrane channels that facilitate the transport of water and small neutral molecules across biological membranes of most living organisms. In plants, aquaporins occur as multiple isoforms reflecting a high diversity of cellular localizations, transport selectivity, and regulation properties. Plant aquaporins are localized in the plasma membrane, endoplasmic reticulum, vacuoles, plastids and, in some species, in membrane compartments interacting with symbiotic organisms. Plant aquaporins can transport various physiological substrates in addition to water. Of particular relevance for plants is the transport of dissolved gases such as carbon dioxide and ammonia or metalloids such as boron and silicon. Structure-function studies are developed to address the molecular and cellular mechanisms of plant aquaporin gating and subcellular trafficking. Phosphorylation plays a central role in these two processes. These mechanisms allow aquaporin regulation in response to signaling intermediates such as cytosolic pH and calcium, and reactive oxygen species. Combined genetic and physiological approaches are now integrating this knowledge, showing that aquaporins play key roles in hydraulic regulation in roots and leaves, during drought but also in response to stimuli as diverse as flooding, nutrient availability, temperature, or light. A general hydraulic control of plant tissue expansion by aquaporins is emerging, and their role in key developmental processes (seed germination, emergence of lateral roots) has been established. Plants with genetically altered aquaporin functions are now tested for their ability to improve plant tolerance to stresses. In conclusion, research on aquaporins delineates ever expanding fields in plant integrative biology thereby establishing their crucial role in plants.
水通道蛋白是一类能够介导水分子和小的中性分子跨生物膜转运的膜通道蛋白。在植物中，水通道蛋白以多种同工型的形式存在，反映了细胞定位、转运选择性和调节特性的高度多样性。植物水通道蛋白定位于质膜、内质网、液泡、质体，在某些物种中还定位于与共生生物相互作用的膜隔室中。植物水通道蛋白除了可以运输水之外，还可以运输各种生理底物。对于植物来说，特别重要的是溶解气体（如二氧化碳和氨）或类金属（如硼和硅）的运输。结构-功能研究的目的是解决植物水通道蛋白门控和亚细胞运输的分子和细胞机制。磷酸化在这两个过程中起着核心作用。这些机制允许水通道蛋白根据胞质 pH 和钙、活性氧等信号中间物进行调节。现在，结合遗传和生理方法正在整合这些知识，表明水通道蛋白在根部和叶片的水力调节、干旱以及各种刺激（如洪水、养分可用性、温度或光照）中发挥着关键作用。水通道蛋白对植物组织扩张的一般水力控制正在出现，它们在关键发育过程（种子萌发、侧根出现）中的作用已经得到确立。现在正在测试具有改变的水通道蛋白功能的植物，以评估它们提高植物对胁迫耐受的能力。总之，对水通道蛋白的研究描绘了植物整合生物学中不断扩展的领域，从而确立了它们在植物中的关键作用。
