Functional adaptations within marine microeukaryotes to polar light regimes

纬向日光照和年光照状况是最稳定的环境信号之一，它们与当地气候条件和水的生化特性一起决定了海洋中的光谱光组成和光强度。海洋生物已经适应了这些当地的光照条件，这反过来又增加了它们的适应性，并有助于各自物种的持久性。在海洋微真核生物中，已知有多种光感受器参与了适应现行光体制的过程。然而，极地海洋微真核生物的光感受器的特异性适应性尚未得到研究，尽管极地光场由于其极端的季节性而具有特殊性，包括长时间的黑暗和长时间的低太阳仰角。因此，我们的目标是了解南大洋的光感受器，特别是初级生产者，它们构成了至关重要的生态系统过程的基础，参与了它们对当地光线条件的适应。该项目的目标包括三个主要主题：1)对环境变化的响应；2)与低纬度地区的联系；3)提高对极地过程和机制的理解。为了实现项目目标，我们将进行不同类型的调查，其结果将提供科学连贯的信息。这包括基于新生成的序列数据以及公开可用的基因组、转录组和超转录组数据的蓝光光感受器的比较分析。这种方法将使我们能够确定特定蓝光光感受器序列的生物地理边界。此外，我们将使用序列信息的蛋白质水平的生物物理表征蓝光光感受器。基于蓝光光感受器引发的细胞内信号和蛋白质水平的生物物理特性，我们将获得它们对蓝光场光谱组成的敏感性评估。总的来说，这个项目的结果将深入了解南大洋中受体在序列进化、敏感性和吸附行为方面的独特之处。就正在进行的全球变化而言，这可以告诉我们对当地光环境的特定适应如何限制范围变化，因为极地地区的温度无疑在上升，但太阳高度却没有上升。

Latitudinal diurnal and annual light regimes are one of the most stable environmental signals and, together with local climatic conditions and biochemical water properties, they determine the spectral light composition and light intensity in the ocean. Marine organisms have adapted to these local light conditions, which in turn increases their fitness and contributes to the persistence of the respective species. In marine microeukaryotes, a variety of photoreceptors are known to be involved in this process of adaptation to the prevailing light regime. However, there are no studies on specific adaptations of photoreceptors in polar marine microeukaryotes, although the polar light field is particular due to its extreme seasonality, including long periods of darkness and long periods of low solar elevation angle. Our goal is therefore to understand how photoreceptors, particularly primary producers, in the Southern Ocean, which form the basis of critically important ecosystem processes, are involved in their adaptations to local light conditions. The goal of this project contributes to 3 overarching themes: 1) Response to Environmental Change, 2) Linkages with Lower Latitudes, and 3) Improved Understanding of Polar Processes and Mechanisms. To achieve the project goal, we will undertake different types of investigations, the results of which will provide scientifically coherent information. This includes a comparative analysis of blue light photoreceptors, based on newly generated sequence data as well as publicly available genome, transcriptome, and metatranscriptome data. This approach will allow us to identify biogeographic boundaries of specific blue light photoreceptor sequences. In addition, we will use the sequence information for a protein-level biophysical characterization of blue light photoreceptors. Based on intracellular signals elicited by blue light photoreceptors and the biophysical characterization at the protein level, we will obtain an assessment of their sensitivity to the spectral composition of the blue light field. Overall, the results of this project will provide insight into how unique the receptors in the Southern Ocean are in terms of sequence evolution, sensitivity, and adsorption behavior. With respect to ongoing global changes, this can inform us on how specific adaptations to local photic environments can limit range shifts, as temperatures in polar regions are undoubtedly rising but solar elevation is not.