Institute of Biology, University of Leipzig, Johannisallee 21-23, D-04103 Leipzig, Germany.
J Exp Bot. 2013 Jan;64(2):483-93. doi: 10.1093/jxb/ers340. Epub 2012 Nov 25.
The objective of the present study was to test the hypothesis that the acclimation to different light intensities in the diatom Phaeodactylum tricornutum is controlled by light quality perception mechanisms. Therefore, semi-continuous cultures of P. tricornutum were illuminated with equal amounts of photosynthetically absorbed radiation of blue (BL), white (WL), and red light (RL) and in combination of two intensities of irradiance, low (LL) and medium light (ML). Under LL conditions, growth rates and photosynthesis rates were similar for all cultures. However, BL cultures were found to be in an acclimation state with an increased photoprotective potential. This was deduced from an increased capacity of non-photochemical quenching, a larger pool of xanthophyll cycle pigments, and a higher de-epoxidation state of xanthophyll cycle pigments compared to WL and RL cultures. Furthermore, in the chloroplast membrane proteome of BL cells, an upregulation of proteins involved in photoprotection, e.g. the Lhcx1 protein and zeaxanthin epoxidase, was evident. ML conditions induced increased photosynthesis rates and a further enhanced photoprotective potential for algae grown under BL and WL. In contrast, RL cultures exhibited no signs of acclimation towards increased irradiance. The data implicate that in diatoms the photoacclimation to high light intensities requires the perception of blue light.
本研究的目的是验证以下假设，即在菱形藻中，对不同光照强度的适应是由光质感知机制控制的。因此，采用等光合有效辐射（photosynthetically absorbed radiation）的蓝（BL）、白（WL）和红（RL）光对半连续培养的菱形藻进行了照明，并结合两种光照强度（低（LL）和中光（ML））。在 LL 条件下，所有培养物的生长率和光合作用率相似。然而，BL 培养物被发现处于适应状态，具有增强的光保护潜力。这可以从非光化学猝灭能力的增加、叶黄素循环色素的更大池以及叶黄素循环色素的去环氧化状态的增加来推断，与 WL 和 RL 培养物相比。此外，在 BL 细胞的叶绿体膜蛋白质组中，参与光保护的蛋白质（例如 Lhcx1 蛋白和玉米黄质环氧化酶）的上调是显而易见的。ML 条件诱导了 BL 和 WL 培养物下光合作用率的增加和进一步增强的光保护潜力。相比之下，RL 培养物没有表现出对增加辐照度的适应迹象。这些数据表明，在硅藻中，对高光强的光适应需要感知蓝光。
