Green microalgae are of the utmost importance to aquatic ecosystems globally, as they are primary producers and major food sources for many organisms. Microalgae of the genus Choricystis are common in Lake Baikal, yet genetic diversity and phylogenetic relationships of the genus are not well known. Nuclear 18S rRNA, plastid rbcL and 16S rRNA gene sequences from open databases were used to investigate the relationships within the genus Choricystis and to specify the phylogeny and diversity of these microalgae in Lake Baikal. Sequences derived from both planktonic Choricystis and endosymbiotic Choricystis living within Baikal endemic sponges were analysed. Species delimitation was performed using bioinformatic methods. Analysis of the three genetic markers showed two major phylogenetic lineages in the genus Choricystis, with the highest genetic diversity observed in the rbcL gene analysis. Two different phylogenetic clusters included sequences of strains with the same species name, Choricystis parasitica (K. Brandt) Pröschold & Darienko, raising the question of hidden diversity within this species. Choricystis algae in Lake Baikal are represented by three genetic variants, two of which are distinct from Choricystis parasitica. Analysis of nuclear and plastid genes in microalgae of the genus Choricystis showed higher genetic diversity than previously thought and a possible endemic speciation in Lake Baikal.

中文翻译：

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贝加尔湖湖藻（藻囊藻，绿藻）属绿色微藻的遗传多样性和系统发育

绿色微藻对全球水生生态系统至关重要，因为它们是许多生物的主要生产者和主要食物来源。贝加尔湖（Lake Baikal）的囊藻属微藻很常见，但该属的遗传多样性和系统发育关系尚不为人所知。来自开放式数据库的核18S rRNA，质体rbc L和16S rRNA基因序列被用于研究脉囊藻属内的关系，并指定贝加尔湖中这些微藻的系统发育和多样性。浮游性胆囊炎和共生性胆囊炎的序列对生活在贝加尔湖流行海绵中的动物进行了分析。使用生物信息学方法进行物种界定。三个遗传标记的分析表明两大进化谱系中属Choricystis，在所观察到的遗传多样性最高RBC L基因分析。两种不同的系统发育簇包括具有相同物种名称的菌株序列，即寄生的库氏囊虫（K. Brandt）Pröschold＆Darienko，这提出了该物种内隐藏多样性的问题。贝加尔湖的藻囊藻由三个遗传变异体代表，其中两个不同于寄生虫藻。属微藻中核和质体基因的分析胆囊菌显示出比以前认为的更高的遗传多样性，并且在贝加尔湖中可能存在地方物种。