is a cyanobacterial genus commonly associated with toxic blooms in lakes and brackish water bodies worldwide, and is a long-term resident of Lake Stechlin, northeastern Germany. In recent decades, shifts in the phosphorus loading and phytoplankton species composition have seen increased biomass of during summer blooms from 1998, peaking around 2005, and declining after 2020. Cyanobacteria are known to rapidly adapt to new environments, facilitated by genome adaptation. To investigate the changes in genomic features that may have occurred in Lake Stechlin during this time of increased phosphorus loading and higher biomass, whole genome sequence analysis was performed on samples of ten akinetes isolated from ten, 1 cm segments of a sediment core, representing a ∼45-year period from 1970 to 2017. Comparison of these genomes with genomes of extant isolates revealed a clade of that clustered with the ADA-6 genus complex, with remarkable genome stability, without gene gain or loss events in response to recent environmental changes. The genome characteristics indicate that this species is suited to a deep-chlorophyll maximum, including additional light-harvesting and phosphorus scavenging genes. Population SNP analysis revealed two sub-populations that shifted in dominance as the lake transitioned between oligotrophic and eutrophic conditions. Overall, the results show little change within the population, despite diversity between extant populations from different geographic locations and the in-lake changes in phosphorus concentrations.

中文翻译：

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德国深湖中蓝细菌 Dolichospermum 基因组结构的长期稳定性

是一种蓝藻属，通常与世界各地湖泊和咸水水体中的有毒水华有关，是德国东北部施特林湖的长期居民。近几十年来，磷负荷和浮游植物物种组成的变化导致夏季水华期间的生物量从 1998 年开始增加，在 2005 年左右达到顶峰，并在 2020 年之后下降。众所周知，在基因组适应的促进下，蓝藻能够快速适应新环境。为了研究施特林湖在磷负荷增加和生物量增加期间可能发生的基因组特征变化，对从沉积物核心的 10 个 1 厘米片段中分离出的 10 个动鱼样本进行了全基因组序列分析，代表了从 1970 年到 2017 年约 45 年。将这些基因组与现有分离株的基因组进行比较，揭示了与 ADA-6 属复合体聚集的进化枝，具有显着的基因组稳定性，没有因最近的环境变化而发生基因增益或丢失事件。基因组特征表明该物种适合深层叶绿素最大值，包括额外的光捕获和磷清除基因。群体 SNP 分析揭示了当湖泊在贫营养和富营养条件之间转变时，两个亚群体的优势发生了变化。总体而言，尽管来自不同地理位置的现有种群之间存在差异以及湖内磷浓度的变化，但结果显示种群内变化不大。