The Cerrado is a biome that corresponds to 24% of Brazil’s territory. Only recently microbial communities of this biome have been investigated. Here we describe for the first time the diversity of archaeal communities from freshwater lake sediments of the Cerrado in the dry season and in the transition period between the dry and rainy seasons, when the first rains occur. Gene libraries were constructed, using Archaea-specific primers for the 16S rRNA and amoA genes. Analysis revealed marked differences between the archaeal communities found in the two seasons. I.1a and I.1c Thaumarchaeota were found in greater numbers in the transition period, while MCG Archaea was dominant on the dry season. Methanogens were only found in the dry season. Analysis of 16S rRNA sequences revealed lower diversity on the transition period. We detected archaeal amoA sequences in both seasons, but there were more OTUs during the dry season. These sequences were within the same cluster as Nitrosotalea devanaterra’s amoA gene. The principal coordinate analysis (PCoA) test revealed significant differences between samples from different seasons. These results provide information on archaeal diversity in freshwater lake sediments of the Cerrado and indicates that rain is likely a factor that impacts these communities.

中文翻译：

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巴西稀树草原湖泊沉积古菌群落的季节性影响。

塞拉多是一个生物群落，相当于巴西领土的 24%。直到最近才对该生物群落的微生物群落进行了调查。在这里，我们首次描述了塞拉多淡水湖沉积物中古菌群落在旱季和旱季和雨季之间的过渡时期的多样性，当时第一场降雨发生。使用用于 16S rRNA 和amoA基因的古细菌特异性引物构建基因文库。分析揭示了两个季节中发现的古菌群落之间的显着差异。I.1a 和 I.1c Thaumarchaeota 在过渡期发现的数量更多，而 MCG Archaea在旱季占主导地位。产甲烷菌仅在旱季被发现。对 16S rRNA 序列的分析显示过渡期的多样性较低。我们在两个季节都检测到古菌amoA序列，但在旱季有更多的 OTU。这些序列与Nitrosotalea devanaterra 的 amoA基因在同一簇内。主坐标分析 (PCoA) 测试显示来自不同季节的样本之间存在显着差异。这些结果提供了关于塞拉多淡水湖沉积物中古菌多样性的信息，并表明降雨可能是影响这些群落的一个因素。