Polishchuk O V
Membranology and Phytochemistry Department, M.G. Kholodny Institute of Botany of NAS of Ukraine, 2 Tereshchenkivska Str, Kyiv, 01004, Ukraine.
Planta. 2021 Feb 3;253(2):58. doi: 10.1007/s00425-020-03553-5.
The data on stress-related changes in the expression and activity of plant carbonic anhydrases (CAs) suggest that they are generally upregulated at moderate stress severity. This indicates probable involvement of CAs in adaptation to drought, high salinity, heat, high light, C deficit, and excess bicarbonate. The changes in CA levels under cold stress are less studied and generally represented by the downregulation of CAs excepting βCA2. Excess Cd and deficit of Zn specifically reduce CA activity and reduce its synthesis. Probable roles of βCAs in stress adaptation include stomatal closure, ROS scavenging and partial compensation for decreased mesophyll CO conductance. βCAs play contrasting roles in pathogen responses, interacting with phytohormone signaling networks. Their role can be either negative or positive, probably depending on the host-pathogen system, pathogen initial titer, and levels of ·NO and ROS. It is still not clear why CAs are suppressed under severe stress levels. It should be noted, that the role of βCAs in the facilitation of CO diffusion and their involvement in redox signaling or ROS detoxication are potentially antagonistic, as they are inactivated by oxidation or nitrosylation. Interestingly, some chloroplastic βCAs may be relocated to the cytoplasm under stress conditions, but the physiological meaning of this effect remains to be studied.
有关植物碳酸酐酶（CAs）表达和活性的应激相关变化的数据表明，它们通常在中等应激强度下被上调。这表明CAs可能参与了对干旱、高盐度、高温、高光、碳亏缺和过量碳酸氢盐的适应。低温胁迫下CA水平的变化研究较少，除βCA2外，通常表现为CAs的下调。过量的镉和锌缺乏会特异性地降低CA活性并减少其合成。βCAs在应激适应中的可能作用包括气孔关闭、活性氧清除以及对叶肉CO传导率降低的部分补偿。βCAs在病原体反应中发挥着相反的作用，与植物激素信号网络相互作用。它们的作用可能是负面的或正面的，这可能取决于宿主 - 病原体系统、病原体初始滴度以及·NO和活性氧的水平。目前尚不清楚为什么在严重应激水平下CAs会受到抑制。应该注意的是，βCAs在促进CO扩散以及参与氧化还原信号传导或活性氧解毒方面的作用可能是相互拮抗的，因为它们会被氧化或亚硝基化而失活。有趣的是，一些叶绿体βCAs在应激条件下可能会重新定位到细胞质中，但这种效应的生理意义仍有待研究。
