The Occurrence of the psbS Gene Product in Chlamydomonas reinhardtii and in Other Photosynthetic Organisms and Its Correlation with Energy Quenching
The Occurrence of the psbS Gene Product in Chlamydomonas reinhardtii and in Other Photosynthetic Organisms and Its Correlation with Energy Quenching
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DOI：
10.1111/j.1751-1097.2008.00456.x
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发表时间：
2008-11-01
影响因子：
3.3
通讯作者：
Caffarri, Stefano
中科院分区：
文献类型：
--
作者：
Bonente, Giulia;Passarini, Francesca;Caffarri, Stefano
为了避免光损伤，光合生物已经发展出逃避或消散多余能量的机制。由光诱导的电子传递引起的管腔过度酸化触发了被激发的叶绿素的猝灭和多余能量转化为热量的耗散。在高等植物中，PsbS蛋白作为低管腔pH的传感器被清楚地证明了。尽管依赖光的能量猝灭是所有光合生物的特性，但可以观察到振幅和动力学的巨大差异，从而提出是否有单一的共同机制在起作用的问题。我们详细研究了PsbS在莱茵衣藻中的表达和积累，并对其在其他藻类和植物中的积累进行了研究。我们发现，在广泛的生长条件下，衣藻中不能检测到PsbS。内源性psbs基因的过表达表明，相应的蛋白不能定位到类囊体膜上。对不同单细胞绿藻的调查显示，与多细胞绿藻相比，抗psbs反应蛋白的积累没有明显的差异。然而，一些单细胞物种表现出高能量猝灭活性，这表明一个不依赖于psbs的机制被激活了。通过对不同物种生长生境和PsbS积累的相关性分析，我们认为在进化过程中，光环境是PsbS功能保存/丧失的决定性因素。
To avoid photodamage, photosynthetic organisms have developed mechanisms to evade or dissipate excess energy. Lumen overacidification caused by light-induced electron transport triggers quenching of excited chlorophylls and dissipation of excess energy into heat. In higher plants participation of the PsbS protein as the sensor of low lumenal pH was clearly demonstrated. Although light-dependent energy quenching is a property of all photosynthetic organisms, large differences in amplitude and kinetics can be observed thus raising the question whether a single common mechanism is in action. We performed a detailed study of PsbS expression/accumulation in Chlamydomonas reinhardtii and investigated its accumulation in other algae and plants. We showed that PsbS cannot be detected in Chlamydomonas under a wide range of growth conditions. Overexpression of the endogenous psbs gene showed that the corresponding protein could not be addressed to the thylakoid membranes. Survey of different unicellular green algae showed no accumulation of anti-PsbS reactive proteins differently from multicellular species. Nevertheless, some unicellular species exhibit high energy quenching activity, suggesting that a PsbS-independent mechanism is activated. By correlating growth habitat and PsbS accumulation in different species, we suggest that during the evolution the light environment has been a determinant factor for the conservation/loss of the PsbS function.