Kurepin Leonid V, Ivanov Alexander G, Zaman Mohammad, Pharis Richard P, Allakhverdiev Suleyman I, Hurry Vaughan, Hüner Norman P A
Department of Biology and The Biotron Center for Experimental Climate Change Research, University of Western Ontario (Western University), 1151 Richmond Street N., London, ON, N6A 5B7, Canada.
Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå, Sweden.
Photosynth Res. 2015 Dec;126(2-3):221-35. doi: 10.1007/s11120-015-0125-x. Epub 2015 Apr 1.
Plants subjected to abiotic stresses such as extreme high and low temperatures, drought or salinity, often exhibit decreased vegetative growth and reduced reproductive capabilities. This is often associated with decreased photosynthesis via an increase in photoinhibition, and accompanied by rapid changes in endogenous levels of stress-related hormones such as abscisic acid (ABA), salicylic acid (SA) and ethylene. However, certain plant species and/or genotypes exhibit greater tolerance to abiotic stress because they are capable of accumulating endogenous levels of the zwitterionic osmolyte-glycinebetaine (GB). The accumulation of GB via natural production, exogenous application or genetic engineering, enhances plant osmoregulation and thus increases abiotic stress tolerance. The final steps of GB biosynthesis occur in chloroplasts where GB has been shown to play a key role in increasing the protection of soluble stromal and lumenal enzymes, lipids and proteins, of the photosynthetic apparatus. In addition, we suggest that the stress-induced GB biosynthesis pathway may well serve as an additional or alternative biochemical sink, one which consumes excess photosynthesis-generated electrons, thus protecting photosynthetic apparatus from overreduction. Glycinebetaine biosynthesis in chloroplasts is up-regulated by increases in endogenous ABA or SA levels. In this review, we propose and discuss a model describing the close interaction and synergistic physiological effects of GB and ABA in the process of cold acclimation of higher plants.
遭受非生物胁迫（如极端高温和低温、干旱或盐度）的植物，通常表现出营养生长减少和繁殖能力降低。这通常与光抑制增加导致的光合作用下降有关，并伴随着胁迫相关激素（如脱落酸（ABA）、水杨酸（SA）和乙烯）内源水平的快速变化。然而，某些植物物种和/或基因型对非生物胁迫表现出更强的耐受性，因为它们能够积累两性离子渗透调节物质——甘氨酸甜菜碱（GB）的内源水平。通过自然合成、外源施用或基因工程积累GB，可增强植物的渗透调节能力，从而提高对非生物胁迫的耐受性。GB生物合成的最后步骤发生在叶绿体中，GB在叶绿体中已被证明在增强对光合装置中可溶性基质和类囊体腔酶、脂质和蛋白质的保护方面发挥关键作用。此外，我们认为胁迫诱导的GB生物合成途径很可能充当额外的或替代的生化库，该生化库消耗过量的光合作用产生的电子，从而保护光合装置免于过度还原。叶绿体中的甘氨酸甜菜碱生物合成通过内源ABA或SA水平的增加而上调。在这篇综述中，我们提出并讨论了一个模型，该模型描述了GB和ABA在高等植物冷驯化过程中的紧密相互作用和协同生理效应。
