Institute of Plant Molecular Biology, Biology Centre, Czech Academy of Sciences, Branišovská 31, 37005, České Budějovice, Czech Republic.
Faculty of Science, University of South Bohemia, Branišovská 1760, 37005, České Budějovice, Czech Republic.
Sci Rep. 2017 Sep 20;7(1):11976. doi: 10.1038/s41598-017-12247-0.
Diatoms greatly contribute to carbon fixation and thus strongly influence the global biogeochemical balance. Capable of chromatic acclimation (CA) to unfavourable light conditions, diatoms often dominate benthic ecosystems in addition to their planktonic lifestyle. Although CA has been studied at the molecular level, our understanding of this phenomenon remains incomplete. Here we provide new data to better explain the acclimation-associated changes under red-enhanced ambient light (RL) in diatom Phaeodactylum tricornutum, known to express a red-shifted antenna complex (F710). The complex was found to be an oligomer of a single polypeptide, Lhcf15. The steady-state spectroscopic properties of the oligomer were also studied. The oligomeric assembly of the Lhcf15 subunits is required for the complex to exhibit a red-shifted absorption. The presence of the red antenna in RL culture coincides with the development of a rounded phenotype of the diatom cell. A model summarizing the modulation of the photosynthetic apparatus during the acclimation response to light of different spectral quality is proposed. Our study suggests that toggling between alternative organizations of photosynthetic apparatus and distinct cell morphologies underlies the remarkable acclimation capacity of diatoms.
硅藻极大地促进了碳的固定，因此强烈影响着全球生物地球化学平衡。硅藻能够进行变色适应（CA）以适应不利的光照条件，除了浮游生物的生活方式外，它们通常还主宰着底栖生态系统。尽管 CA 已经在分子水平上进行了研究，但我们对这一现象的理解仍然不完整。在这里，我们提供了新的数据，以更好地解释在增强的环境光（RL）下硅藻 Phaeodactylum tricornutum 中与适应相关的变化，众所周知，这种硅藻表达了一个红移天线复合物（F710）。该复合物被发现是单个多肽 Lhcf15 的寡聚物。还研究了寡聚物的稳态光谱特性。Lhcf15 亚基的寡聚组装对于复合物表现出红移吸收是必需的。在 RL 培养中存在红色天线与硅藻细胞的圆形表型的发展同时发生。提出了一个总结在不同光谱质量的光适应反应过程中光合作用器官的调制的模型。我们的研究表明，在不同的细胞形态之间切换光合作用器官的替代组织是硅藻显著适应能力的基础。
