Photosystem II Subunit PsbS Is Involved in the Induction of LHCSR Protein-dependent Energy Dissipation in Chlamydomonas reinhardtii
Photosystem II Subunit PsbS Is Involved in the Induction of LHCSR Protein-dependent Energy Dissipation in Chlamydomonas reinhardtii
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DOI：
10.1074/jbc.m116.737312
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发表时间：
2016-08-01
影响因子：
4.8
通讯作者：
Jahns, Peter
中科院分区：
文献类型：
--
作者：
Correa-Galvis, Viviana;Redekop, Petra;Jahns, Peter
过量激发能的非光化学猝灭是光合生物重要的光保护机制。在拟南芥中，高淬灭能力是组成性存在的，并依赖于PsbS蛋白。在绿色莱茵衣藻中，非光化学淬灭在高光驯化后被激活，并且需要光捕获复合应激相关（LHCSR）蛋白的积累。PsbS蛋白在C.目前尚未报道reinhardtii。在这里，我们表明，PsbS是一个光诱导蛋白在C。reinhardtii，其积累在强光下进一步控制CO2有效性。PsbS积累后几个小时的强光照射在低CO2。然而，在高CO2下，PsbS仅在高光下瞬时表达，并在高光暴露1小时后降解。PsbS积累与增强的非光化学猝灭能力在高光驯化的细胞生长在低CO2。然而，在LHCSR缺陷突变体中，PsbS不能补偿LHCSR的功能。敲低PsbS积累导致非光化学猝灭能力和LHCSR3积累的减少。我们的数据表明，PsbS是必不可少的激活非光化学猝灭在C。reinhardtii，可能是通过促进光系统II天线中LHCSR3依赖性淬灭激活所需的构象变化。
Non-photochemical quenching of excess excitation energy is an important photoprotective mechanism in photosynthetic organisms. In Arabidopsis thaliana, a high quenching capacity is constitutively present and depends on the PsbS protein. In the green alga Chlamydomonas reinhardtii, non-photochemical quenching becomes activated upon high light acclimation and requires the accumulation of light harvesting complex stress-related (LHCSR) proteins. Expression of the PsbS protein in C. reinhardtii has not been reported yet. Here, we show that PsbS is a light-induced protein in C. reinhardtii, whose accumulation under high light is further controlled by CO2 availability. PsbS accumulated after several hours of high light illumination at low CO2. At high CO2, however, PsbS was only transiently expressed under high light and was degraded after 1 h of high light exposure. PsbS accumulation correlated with an enhanced non-photochemical quenching capacity in high light-acclimated cells grown at low CO2. However, PsbS could not compensate for the function of LHCSR in an LHCSR-deficient mutant. Knockdown of PsbS accumulation led to reduction of both non-photochemical quenching capacity and LHCSR3 accumulation. Our data suggest that PsbS is essential for the activation of non-photochemical quenching in C. reinhardtii, possibly by promoting conformational changes required for activation of LHCSR3-dependent quenching in the antenna of photosystem II.