The exposure of microalgae and plants to low UV-C radiation dosages can improve their biomass composition and stress tolerance. Despite UV-C sharing these effects with UV-A/B but at much lower dosages, UV-C sensing and signal mechanisms are still mostly unknown. Thus, we have described and integrated the proteometabolomic and physiological changes occurring in Chlamydomonas reinhardtii—a simple Plantae model—into the first 24 h after a short and low-intensity UV-C irradiation in order to reconstruct the microalgae response system to this stress. The microalgae response was characterized by increased redox homeostasis, ROS scavenging and protein damage repair/avoidance elements. These processes were upregulated along with others related to the modulation of photosynthetic electron flux, carbon fixation and C/N metabolism. These changes, attributed to either direct UV-C-, ROS- or redox unbalances-associated damage, trigger a response process involving novel signaling intermediaries and effectors such as the translation modulator FAP204, a PP2A-like protein and a novel DYRK kinase. These elements were found linked to the modulation of Chlamydomonas biomass composition (starch accumulation) and proliferation, within an UV-C response probably modulated by different epigenetic factors. Chosen multiomics integration approach was able to describe many fast changes, including biomass composition and ROS stress tolerance, as a response to a low-intensity UV-C stress. Moreover, the employed omics and systems biology approach placed many previously unidentified protein and metabolites at the center of these changes. These elements would be promising targets for the characterization of this stress response in microalgae and plants and the engineering of more productive microalgae strains.

中文翻译：

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低 UV-C 应激通过涉及新型信号和效应器的蛋白质组学和代谢组学变化来调节莱茵衣藻生物量组成和氧化应激反应。

微藻和植物暴露于低 UV-C 辐射剂量可以改善它们的生物量组成和胁迫耐受性。尽管 UV-C 与 UV-A/B 共享这些效应，但剂量要低得多，但 UV-C 传感和信号机制仍然大多未知。因此，我们已经描述并将莱茵衣藻（一种简单的植物模型）中发生的蛋白质代谢组学和生理学变化整合到短时间和低强度 UV-C 照射后的前 24 小时，以重建微藻对这种压力的反应系统。微藻反应的特点是氧化还原稳态、活性氧清除和蛋白质损伤修复/避免元素增加。这些过程与其他与光合电子通量调节、碳固定和 C/N 代谢相关的过程都被上调。这些变化，归因于直接的 UV-C-、ROS- 或氧化还原失衡相关的损伤，触发了涉及新型信号中介和效应器的反应过程，例如翻译调节剂 FAP204、PP2A 样蛋白和新型 DYRK 激酶。发现这些元素与衣藻生物量组成（淀粉积累）和增殖的调节有关，在可能受不同表观遗传因素调节的 UV-C 反应中。选择的多组学整合方法能够描述许多快速变化，包括生物量组成和 ROS 胁迫耐受性，作为对低强度 UV-C 胁迫的响应。此外，所采用的组学和系统生物学方法将许多以前未鉴定的蛋白质和代谢物置于这些变化的中心。