Graduate School of Science, Kobe University, Kobe, 657-8501, Japan.
Innovation Center, Nippon Flour Mills Co., Ltd, Atsugi, 243-0041, Japan.
Photosynth Res. 2020 Dec;146(1-3):87-93. doi: 10.1007/s11120-020-00713-2. Epub 2020 Jan 22.
Diatoms are a major group of microalgae in marine and freshwater environments. To utilize the light energy in blue to green region, diatoms possess unique antenna pigment-protein complexes, fucoxanthin chlorophyll a/c-binding proteins (FCPs). Depending on light qualities and quantities, diatoms form FCPs with different energies: normal-type and red-shifted FCPs. In the present study, we examined changes in light-harvesting and energy-transfer processes of a diatom Chaetoceros gracilis cells grown using white- and single-colored light-emitting diodes (LEDs), by means of time-resolved fluorescence spectroscopy. The blue LED, which is harvested by FCPs, modified energy transfer involving CP47, and suppressed energy transfer to PSI. Under the red-LED conditions, which is absorbed by both FCPs and PSs, energy transfer to PSI was enhanced, and the red-shifted FCP appeared. The red-shifted FCP was also recognized under the green- and yellow-LEDs, suggesting that lack of the shorter-wavelength light induces the red-shifted FCP. Functions of the red-shifted FCPs are discussed.
硅藻是海洋和淡水环境中一类主要的微藻。为了利用蓝绿光区的光能，硅藻拥有独特的天线色素-蛋白复合物，即叶黄素叶绿素 a/c 结合蛋白（FCPs）。根据光质和光量的不同，硅藻形成具有不同能量的 FCPs：正常型和红移 FCPs。在本研究中，我们通过时间分辨荧光光谱法，研究了使用白色和单色发光二极管（LED）培养的硅藻角毛藻细胞中光捕获和能量传递过程的变化。蓝色 LED 被 FCPs 吸收，改变了涉及 CP47 的能量转移，并抑制了向 PSI 的能量转移。在红色 LED 条件下，FCPs 和 PS 都能吸收，向 PSI 的能量转移增强，并且出现了红移 FCP。在绿光和黄光 LED 下也能识别出红移 FCP，表明缺少较短波长的光会诱导红移 FCP。讨论了红移 FCP 的功能。
