The harsh environments and high biodiversity of the Qinghai–Tibet Plateau (QTP) provide an ideal natural laboratory for studies on adaptive evolution. Low temperature and intense UV-B radiation are the main abiotic stresses to plants at high altitudes. The rapid development of RNA sequencing has enabled us to investigate the molecular adaptations of plants that thrive in the QTP at the genomic level. Despite the ecological importance of Oocystis algae on the plateau, the genetic mechanisms of the adaptations of these algae to this high-altitude environment remain poorly understood. Here, we sequenced and assembled the transcriptomes of Oocystis marina and Oocystis sp. LXD-20, and undertook comparative transcriptomic and evolutionary analyses to reveal their adaptive strategies. Our results identified 348 positively selected genes in Oocystis algae, and functional analyses indicated that many of these positively selected genes were associated with adaptation to abiotic stresses, such as antioxidative response, DNA repair mechanisms, translation, and post-translational modifications. We also identified the cold-responsive and UV-B-responsive genes in O. marina and Oocystis sp. LXD-20, and revealed the transcriptional regulation strategies under stress conditions. Our analyses provided a wealth of sequence data to serve as reference transcriptomes for future studies, and shed light on the adaptive strategies of green algae that live in the QTP.

中文翻译：

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两种卵囊藻的综合转录组分析提供了对青藏高原适应的见解

青藏高原 (QTP) 的恶劣环境和高度生物多样性为研究适应性进化提供了理想的天然实验室。低温和强烈的 UV-B 辐射是高海拔植物的主要非生物胁迫。RNA 测序的快速发展使我们能够在基因组水平上研究在 QTP 中茁壮成长的植物的分子适应性。尽管卵囊藻在高原上具有生态重要性，但这些藻类适应这种高海拔环境的遗传机制仍然知之甚少。在这里，我们对Oocystis marina和Oocystis的转录组进行了测序和组装sp. LXD-20，并进行了比较转录组学和进化分析，以揭示它们的适应性策略。我们的结果在卵囊藻中鉴定了 348 个正选基因，功能分析表明这些正选基因中有许多与对非生物胁迫的适应有关，例如抗氧化反应、DNA 修复机制、翻译和翻译后修饰。我们还鉴定了O. marina和Oocystis 中的冷响应和 UV-B 响应基因sp. LXD-20，揭示了应激条件下的转录调控策略。我们的分析提供了丰富的序列数据，可作为未来研究的参考转录组，并阐明生活在 QTP 中的绿藻的适应性策略。