Main conclusionThe molecular and physiological mechanisms of glycinebetaine stabilizing photosystem II complex under abiotic stresses are discussed, helping to address food shortage problems threatening the survival of growing population.AbstractIn the backdrop of climate change, the frequency, dimensions and duration of extreme events have increased sharply, which may have unintended consequences for agricultural. The acclimation of plants to a constantly changing environment involves the accumulation of compatible solutes. Various compatible solutes enable plants to tolerate abiotic stresses, and glycinebetaine (GB) is one of the most-studied. The biosynthesis and accumulation of GB appear in numerous plant species, especially under environmental stresses. The exogenous application of GB and GB-accumulating transgenic plants have been proven to further promote plant development under stresses. Early research on GB focused on the maintenance of osmotic potential in plants. Subsequent experimental evidence demonstrated that it also protects proteins including the photosystem II complex (PSII) from denaturation and deactivation. As reviewed here, multiple experimental evidences have indicated considerable progress in the roles of GB in stabilizing PSII under abiotic stresses. Based on these advances, we’ve concluded two effects of GB on PSII: (1) it stabilizes the structure of PSII by protecting extrinsic proteins from dissociation or by promoting protein synthesize; (2) it enhances the oxygen-evolving activity of PSII or promotes the repair of the photosynthetic damage of PSII.

中文翻译：

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甘氨酸甜菜碱在稳定非生物胁迫下光系统 II 复合物结构和功能中的重要作用

主要结论讨论了非生物胁迫下甘氨酸甜菜碱稳定光系统II复合物的分子和生理机制，有助于解决威胁不断增长的人口生存的粮食短缺问题。摘要在气候变化背景下，极端事件的频率、规模和持续时间急剧增加，这可能对农业产生意想不到的后果。植物对不断变化的环境的适应涉及相容溶质的积累。各种相容的溶质使植物能够耐受非生物胁迫，而甘氨酸甜菜碱 (GB) 是研究最多的溶质之一。GB的生物合成和积累出现在许多植物物种中，尤其是在环境胁迫下。GB和积累GB的转基因植物的外源应用已被证明可以进一步促进植物在胁迫下的发育。GB的早期研究集中在植物渗透势的维持上。随后的实验证据表明，它还可以保护包括光系统 II 复合物 (PSII) 在内的蛋白质免于变性和失活。如本文所述，多个实验证据表明 GB 在非生物胁迫下稳定 PSII 的作用取得了相当大的进展。基于这些进展，我们总结出GB对PSII的两个影响：（1）它通过保护外源蛋白不解离或促进蛋白质合成来稳定PSII的结构；(2)增强PSII的析氧活性或促进PSII光合损伤的修复。