Oxidation of P700 in photosystem I is essential for the growth of cyanobacteria
Oxidation of P700 in photosystem I is essential for the growth of cyanobacteria
复制标题
光系统 I 中 P700 的氧化对于蓝藻的生长至关重要
DOI：
10.1104/pp.16.01227
复制
发表时间：
2016
期刊：
影响因子：
7.4
通讯作者：
Miyake C
中科院分区：
文献类型：
--
作者：
Shimakawa G;Shaku K;Miyake C
光系统I(PSI)的光抑制对产氧光养生物是致命的。然而，目前尚不清楚光损伤是如何发生的，也不清楚富氧光养生物是如何防止光损伤的。在这里，我们提供了保持P700(PSI中的反应中心叶绿素)氧化保护PSI的证据。以前的研究表明，PSI光抑制不存在于两种蓝藻--聚球藻中。PCC6803和细长聚球藻PCC7942，当光合作用CO2固定在低CO2分压下被抑制时，即使在缺乏黄铁蛋白(Flv)的突变体中也是如此，这介导了交替电子流。在聚球藻中缺乏流感病毒。然而，PCC7002(S.7002)直接与二氧化碳限制条件下的生长减慢和PSI光损伤有关。不像聚球藻。PCC 6803和.在没有FLV的情况下，在CO2限制光照条件下，拉长的PCC 7942和S.7002降低了P700，导致PSI和光合作用活性都下降。即使在正常的大气CO2浓度下，S.7002突变株的生长也比野生型的要慢。因此，P700的氧化对于保护PSI抗光抑制是必不可少的。在这里，我们提出了不同的策略来减轻蓝藻的PSI光抑制。
The photoinhibition of photosystem I (PSI) is lethal to oxygenic phototrophs. Nevertheless, it is unclear how photodamage occurs or how oxygenic phototrophs prevent it. Here, we provide evidence that keeping P700 (the reaction center chlorophyll in PSI) oxidized protects PSI. Previous studies have suggested that PSI photoinhibition does not occur in the two model cyanobacteria,Synechocystissp. PCC 6803 andSynechococcus elongatusPCC 7942, when photosynthetic CO2fixation was suppressed under low CO2partial pressure even in mutants deficient in flavodiiron protein (FLV), which mediates alternative electron flow. The lack of FLV inSynechococcussp. PCC 7002 (S. 7002), however, is linked directly to reduced growth and PSI photodamage under CO2-limiting conditions. UnlikeSynechocystissp. PCC 6803 andS. elongatusPCC 7942, S. 7002 reduced P700 during CO2-limited illumination in the absence of FLV, resulting in decreases in both PSI and photosynthetic activities. Even at normal air CO2concentration, the growth of S. 7002 mutant was retarded relative to that of the wild type. Therefore, P700 oxidation is essential for protecting PSI against photoinhibition. Here, we present various strategies to alleviate PSI photoinhibition in cyanobacteria.