Centre Algatech, Institute of Microbiology, Academy of Sciences of the Czech Republic, Opatovický mlýn, 379 81, Třeboň, Czech Republic.
Faculty of Science, University of South Bohemia, Branišovská 31, 37005, Czech Budejovice, Czech Republic.
Photosynth Res. 2018 Mar;135(1-3):263-274. doi: 10.1007/s11120-017-0385-8. Epub 2017 Apr 12.
It has previously been shown that the long-term treatment of Arabidopsis thaliana with the chloroplast inhibitor lincomycin leads to photosynthetic membranes enriched in antennas, strongly reduced in photosystem II reaction centers (PSII) and with enhanced nonphotochemical quenching (NPQ) (Belgio et al. Biophys J 102:2761-2771, 2012). Here, a similar physiological response was found in the microalga Chromera velia grown under high light (HL). In comparison to cells acclimated to low light, HL cells displayed a severe re-organization of the photosynthetic membrane characterized by (1) a reduction of PSII but similar antenna content; (2) partial uncoupling of antennas from PSII; (3) enhanced NPQ. The decrease in the number of PSII represents a rather unusual acclimation response compared to other phototrophs, where a smaller PSII antenna size is more commonly found under high light. Despite the diminished PSII content, no net damage could be detected on the basis of the Photosynthesis versus irradiance curve and electron transport rates pointing at the excess capacity of PSII. We therefore concluded that the photoinhibition is minimized under high light by a lower PSII content and that cells are protected by NPQ in the antennas.
先前的研究表明，长期用叶绿体抑制剂林可霉素处理拟南芥会导致富含天线的光合膜、光系统 II 反应中心（PSII）显著减少以及非光化学猝灭（NPQ）增强（Belgio 等人，《生物物理期刊》102:2761-2771，2012）。在这里，在高光下生长的微藻 Chromera velia 中也发现了类似的生理反应。与适应低光的细胞相比，高光下的细胞表现出光合作用膜的严重重组，其特征为：（1）PSII 减少，但天线含量相似；（2）天线与 PSII 的部分解偶联；（3）NPQ 增强。与其他光养生物相比，PSII 数量的减少是一种相当不寻常的适应反应，因为在高光下更常见的是 PSII 天线尺寸更小。尽管 PSII 含量减少，但根据光合作用与辐照度曲线和电子传递速率，并没有检测到净损伤，这表明 PSII 具有过剩的容量。因此，我们得出结论，在高光下，较低的 PSII 含量使光抑制最小化，并且 NPQ 保护了天线中的细胞。
