Green algal species of spherical cell shape are generally considered to belong to the genus Chlorella, which are mostly freshwater or terrestrial organisms. Phylogenetic studies have shown that this genus is polyphyletic and belongs to different classes. However, until now, only freshwater or terrestrial strains have been studied. Here we investigated 11 strains of ‘marine’ Chlorella deposited in public culture collections, which we studied using an integrative approach. These strains were largely isolated from marine rock pools and brackish estuaries. SSU and ITS regions of the nuclear encoded ribosomal DNA were sequenced, ribosomal secondary structures were analysed and cell morphology, salinity tolerance and reproduction were examined. Our results showed that the marine strains are also of polyphyletic origin. Surprisingly, three marine isolates belong to Chlorella vulgaris according to the phylogenetic analyses, but showed a high phenotypic plasticity. Whereas these strains showed the typical morphology of C. vulgaris under freshwater conditions, they increased the cell shape and formed cell packages under marine conditions. In contrast, the other investigated strains showed no changes after changing the media. Two of the investigated strains belong to the genus Chloroidium, and those remaining represent a new genus, Droopiella.

中文翻译：

---

是否有任何真正的海洋小球藻物种？海洋小球藻样生物的分子系统发育评估和生态学，包括 Droopiella gen 的描述。十一月

球形细胞形状的绿藻物种通常被认为属于小球藻属，它们大多是淡水或陆生生物。系统发育研究表明，该属是多系的，属于不同的纲。然而，到目前为止，只研究了淡水或陆地菌株。在这里，我们调查了 11 株保存在公共培养物保藏中心的“海洋”小球藻，我们使用综合方法对其进行了研究。这些菌株主要是从海相岩石池和咸水河口中分离出来的。对核编码的核糖体 DNA 的 SSU 和 ITS 区域进行测序，分析核糖体二级结构并检查细胞形态、耐盐性和繁殖。我们的结果表明，海洋菌株也是多系起源的。出奇，根据系统发育分析，三个海洋分离物属于小球藻，但表现出较高的表型可塑性。虽然这些菌株在淡水条件下表现出典型的 C. vulgaris 形态，但它们在海洋条件下增加了细胞形状并形成了细胞包。相比之下，其他研究的菌株在更换培养基后没有变化。两个研究的菌株属于 Chloroidium 属，其余的代表一个新属 Droopiella。其他研究的菌株在更换培养基后没有显示出任何变化。两个研究的菌株属于 Chloroidium 属，其余的代表一个新属 Droopiella。其他研究的菌株在更换培养基后没有显示出任何变化。两个研究的菌株属于 Chloroidium 属，其余的代表一个新属 Droopiella。