Ramos Vitor M C, Castelo-Branco Raquel, Leão Pedro N, Martins Joana, Carvalhal-Gomes Sinda, Sobrinho da Silva Frederico, Mendonça Filho João G, Vasconcelos Vitor M
Faculty of Sciences, University of PortoPorto, Portugal.
Interdisciplinary Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of PortoMatosinhos, Portugal.
Front Microbiol. 2017 Jun 30;8:1233. doi: 10.3389/fmicb.2017.01233. eCollection 2017.
Microbial mats are complex, micro-scale ecosystems that can be found in a wide range of environments. In the top layer of photosynthetic mats from hypersaline environments, a large diversity of cyanobacteria typically predominates. With the aim of strengthening the knowledge on the cyanobacterial diversity present in the coastal lagoon system of Araruama (state of Rio de Janeiro, Brazil), we have characterized three mat samples by means of a polyphasic approach. We have used morphological and molecular data obtained by culture-dependent and -independent methods. Moreover, we have compared different classification methodologies and discussed the outcomes, challenges, and pitfalls of these methods. Overall, we show that Araruama's lagoons harbor a high cyanobacterial diversity. Thirty-six unique morphospecies could be differentiated, which increases by more than 15% the number of morphospecies and genera already reported for the entire Araruama system. Morphology-based data were compared with the 16S rRNA gene phylogeny derived from isolate sequences and environmental sequences obtained by PCR-DGGE and pyrosequencing. Most of the 48 phylotypes could be associated with the observed morphospecies at the order level. More than one third of the sequences demonstrated to be closely affiliated (best BLAST hit results of ≥99%) with cyanobacteria from ecologically similar habitats. Some sequences had no close relatives in the public databases, including one from an isolate, being placed as "loner" sequences within different orders. This hints at hidden cyanobacterial diversity in the mats of the Araruama system, while reinforcing the relevance of using complementary approaches to study cyanobacterial diversity.
微生物席是复杂的微观生态系统，可在多种环境中找到。在高盐环境光合席的顶层，通常以种类繁多的蓝细菌为主。为了加强对巴西里约热内卢州阿拉鲁阿马沿海泻湖系统中蓝细菌多样性的了解，我们采用多相方法对三个席样进行了特征分析。我们使用了通过依赖培养和不依赖培养方法获得的形态学和分子数据。此外，我们比较了不同的分类方法，并讨论了这些方法的结果、挑战和缺陷。总体而言，我们表明阿拉鲁阿马的泻湖拥有高度的蓝细菌多样性。可以区分出36个独特的形态物种，这使得整个阿拉鲁阿马系统中已报道的形态物种和属的数量增加了15%以上。将基于形态学的数据与从分离株序列以及通过PCR-DGGE和焦磷酸测序获得的环境序列推导的16S rRNA基因系统发育进行了比较。48个系统发育型中的大多数在目水平上可以与观察到的形态物种相关联。超过三分之一的序列显示与来自生态相似栖息地的蓝细菌密切相关（最佳BLAST比对结果≥99%）。一些序列在公共数据库中没有近亲，包括一个来自分离株的序列，被列为不同目中的“孤独”序列。这暗示了阿拉鲁阿马系统席中隐藏的蓝细菌多样性，同时强化了使用互补方法研究蓝细菌多样性的相关性。
