Glycinebetaine alleviates the inhibitory repair of photosystem II effect of moderate heat stress on the during photoinhibition
Glycinebetaine alleviates the inhibitory repair of photosystem II effect of moderate heat stress on the during photoinhibition
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DOI：
10.1016/j.bbabio.2007.10.005
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发表时间：
2007-12-01
影响因子：
4.3
通讯作者：
Murata, Norio
中科院分区：
文献类型：
--
作者：
Allakhverdiev, Suleyman I.;Los, Dmitry A.;Murata, Norio
利用细菌基因coda转化胆碱氧化酶使聚球藻成为可能。当胆碱被外源补充时，PCC7942细胞积累甘氨酸甜菜碱。首先，我们观察到甜菜碱在黑暗中对拍打诱导的光系统II(PSII)失活的两种保护作用：尾巴转基因使放氧复合体的失活温度范围从40-52℃(46℃时一半失活)移动到46-60℃(54℃时一半失活)，以及光化学反应中心的温度范围从44-55℃(51℃时一半失活)转移到52-63℃(58℃时一半失活)。然而，在光下，PSII对热胁迫更敏感；当适度的热胁迫，如40摄氏度，与光胁迫结合时，PSII迅速失活，尽管当这些胁迫单独应用时，既不会使放氧复合体失活，也不会使光化学反应中心失活。我们的研究进一步证明，适度的热胁迫在光抑制过程中抑制了D1蛋白从头合成部位PSII的修复，但不直接加速光损伤。尾巴转基因和甜菜碱的积累通过加速D1蛋白的合成，缓解了适度热胁迫对PSII修复的抑制效应。我们提出了蓝藻光合作用的一个假设方案，即适度的热应激抑制转换机制，而甜菜碱保护它免受热诱导的失活。(C)2007 Elsevier B.V.保留所有权利。
Transformation with the bacterial gene codA for choline oxidase allows Synechococcus sp. PCC 7942 cells to accumulate glycinebetaine when choline is supplemented exogenously. First, we observed two types of protective effect of glycinebetaine against beat-induced inactivation of photosystem II (PSII) in darkness; the codA transgene shifted the temperature range of inactivation of the oxygen-evolving complex from 40-52 degrees C (with half inactivation at 46 degrees C) to 46-60 degrees C (with half inactivation at 54 degrees C) and that of the photochemical reaction center from 44-55 degrees C (with half inactivation at 51 degrees C) to 52-63 degrees C (with half inactivation at 58 degrees C). However, in light, PSII was more sensitive to heat stress; when moderate heat stress, such as 40 degrees C, was combined with light stress, PSII was rapidly inactivated, although these stresses, when applied separately, did not inactivate either the oxygen-evolving complex or the photochemical reaction center. Further our studies demonstrated that the moderate heat stress inhibited the repair of PSII during photoinhibition at the site of synthesis de novo of the D1 protein but did not accelerate the photodamage directly. The codA transgene and, thus, the accumulation of glycinebetaine alleviated such an inhibitory effect of moderate heat stress on the repair of PSII by accelerating the synthesis of the D1 protein. We propose a hypothetical scheme for the cyanobacterial photosynthesis that moderate heat stress inhibits the translation machinery and glycinebetaine protects it against the heat-induced inactivation. (C) 2007 Elsevier B.V. All rights reserved.