In nature, photosynthetic organisms are exposed to highly dynamic environmental conditions where the excitation energy and electron flow in the photosynthetic apparatus need to be continuously modulated. Fluctuations in incident light are particularly challenging because they drive oversaturation of photosynthesis with consequent oxidative stress and photoinhibition. Plants and algae have evolved several mechanisms to modulate their photosynthetic machinery to cope with light dynamics, such as thermal dissipation of excited chlorophyll states (non-photochemical quenching, NPQ) and regulation of electron transport. The regulatory mechanisms involved in the response to light dynamics have adapted during evolution, and exploring biodiversity is a valuable strategy for expanding our understanding of their biological roles. In this work, we investigated the response to fluctuating light in Nannochloropsis gaditana, a eukaryotic microalga of the phylum Heterokonta originating from a secondary endosymbiotic event. Nannochloropsis gaditana is negatively affected by light fluctuations, leading to large reductions in growth and photosynthetic electron transport. Exposure to light fluctuations specifically damages photosystem I, likely because of the ineffective regulation of electron transport in this species. The role of NPQ, also assessed using a mutant strain specifically depleted of this response, was instead found to be minor, especially in responding to the fastest light fluctuations.

中文翻译：

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响应内生藻类次生藻Nanonochloropsis gaditana中的波动光的光合作用调节。

在自然界中，光合作用生物暴露于高度动态的环境条件下，在该环境条件下，需要不断调节光合作用设备中的激发能和电子流。入射光的波动特别具有挑战性，因为它们会导致光合作用的过饱和，进而导致氧化应激和光抑制。植物和藻类已经进化出多种机制来调节其光合作用机制，以应对光动力学，例如激发叶绿素状态的热耗散（非光化学猝灭，NPQ）和电子传递的调节。对光动力的响应所涉及的调节机制在进化过程中已经适应，探索生物多样性是扩大我们对它们的生物学作用的理解的宝贵策略。在这项工作中，我们调查了Nannochloropsis gaditana，杂种动物门的真核微藻源于继发性内共生事件的对光的响应。Nannochloropsis gaditana受到光波动的负面影响，导致生长和光合电子传输的大幅减少。暴露在光波中会特别破坏光系统I，这可能是因为该物种中电子传输的调控无效。NPQ的作用也很小，特别是在响应最快的光波动时，也使用较小的突变株来评估，而NPQ的作用也被专门消除了这种响应的突变株评估。Nannochloropsis gaditana受到光波动的负面影响，导致生长和光合电子传输的大幅减少。暴露在光波中会特别破坏光系统I，这可能是因为该物种中电子传输的调控无效。NPQ的作用也很小，特别是在对最快的光波动做出响应时，NPQ的作用也很小，而NPQ的作用也使用这种反应特别消除的突变株来评估。Nannochloropsis gaditana受到光波动的负面影响，导致生长和光合电子传输的大幅减少。暴露在光波中会特别破坏光系统I，这可能是因为该物种中电子传输的调控无效。NPQ的作用也很小，特别是在响应最快的光波动时，也使用较小的突变株来评估，而NPQ的作用也被专门消除了这种响应的突变株评估。