Abstract：
The green algae of the genus Ancylonema, which belong to the zygnematophytes, are prevalent colonizers of glaciers worldwide. They display a striking reddish-brown pigmentation in their natural environment, due to vacuolar compounds related to gallic acid. This pigmentation causes glacier darkening when these algae bloom, leading to increased melting rates. The Ancylonema species known so far are true psychrophiles, which hinders experimental work and limits our understanding of these algae. For instance, the biosynthesis, triggering factors, and biological function of Ancylonema\'s secondary pigments remain unknown. In this study, we introduce a mesophilic Ancylonema species, A. palustre sp. nov., from temperate moorlands. This species forms the sister lineage to all known psychrophilic strains. Despite its morphological similarity to the latter, it exhibits unique autecological and photophysiological characteristics. It allows us to describe vegetative and sexual cellular processes in great detail. We also conducted experimental tests for abiotic factors that induce the secondary pigments of zygnematophytes. We found that low nutrient conditions combined with ultraviolet B radiation result in vacuolar pigmentation, suggesting a sunscreen function. Our thriving, bacteria-free cultures of Ancylonema palustre will enable comparative genomic studies of mesophilic and extremophilic zygnematophytes. These studies may provide insights into how Ancylonema species colonized the world\'s glaciers.
摘要：
Ancylonema属的绿藻，属于受精卵植物，是全世界冰川的普遍殖民者。它们在自然环境中表现出惊人的红棕色色素沉着，由于与没食子酸有关的液泡化合物。当这些藻类开花时，这种色素沉着会导致冰川变黑，导致熔化速率增加。到目前为止已知的Ancylonema物种是真正的嗜冷者，这阻碍了实验工作，限制了我们对这些藻类的理解。例如,生物合成，触发因素，Ancylonema的次级色素的生物学功能仍然未知。在这项研究中,我们介绍了一种嗜温的Ancylonema物种，A.palustresp.11月。,来自温带沼地。该物种形成了所有已知的嗜冷菌株的姐妹谱系。尽管与后者的形态相似，它表现出独特的自共晶和光生理特征。它使我们能够非常详细地描述植物和性细胞过程。我们还对诱导子植物次生色素的非生物因素进行了实验测试。我们发现，低营养条件结合紫外线B辐射导致液泡色素沉着，暗示防晒功能。我们的欣欣向荣，无细菌培养的Ancylonemapalustre将使嗜温和极端嗜性合子植物的比较基因组研究成为可能。这些研究可以提供有关Ancylonema物种如何在世界冰川中定居的见解。
