ABSTRACT

We analysed and characterized the cyanobacteria in microbialites of Alchichica crater lake over a depth gradient, from 3 to 30 m. A polyphasic approach was followed using morphometry, optical and epifluorescence microscopy, and molecular methods. Regions V3–V4 of the 16S rRNA conserved for cyanobacteria were amplified and used for clone library construction. Independently, a NGS library was constructed using the V4 region of the 16S rRNA. To complement the analysis, eight monocultures of cyanobacteria were isolated from microbialites, which were also characterized by microscopy and 16S rRNA sequencing. In total, we described 18 genera of cyanobacteria isolated from microbialites of Alchichica crater lake. The distribution pattern suggests that on the surface there were mostly Nostocales and filamentous Synechococcales, while at depth we found single-celled Synechococcales. Pleurocapsales and Chroococcales were found at all depths, increasing in abundance at 20 and 30 m.

摘要

我们在 3 到 30 m 的深度梯度上分析和表征了 Alchichica 火山口湖微生物岩中的蓝藻。使用形态测量学、光学和落射荧光显微镜以及分子方法遵循多相方法。蓝藻保守的 16S rRNA 的 V3-V4 区域被扩增并用于克隆文库构建。独立地，使用 16S rRNA 的 V4 区域构建了一个 NGS 文库。为了补充分析，从微生物群落中分离出八种蓝藻单一培养物，并通过显微镜和 16S rRNA 测序对其进行了表征。我们总共描述了从 Alchichica 火山口湖微生物岩中分离出的 18 个蓝藻属。分布模式表明，在地表上主要是Nostocales和丝状聚球藻，而在深处，我们发现了单细胞聚球藻。在所有深度都发现了 Pleurocapsales 和 Chroococcales，在 20 和 30 m 处的丰度增加。