The Cerrado biome corresponds to an extensive area of Brazil and is considered a biodiversity hotspot. Frequent fires are a natural feature in this biome and have influences on vegetation structure and composition. However, continuous anthropogenic actions are promoting changes in fire frequency and seasonality. Despite the high biodiversity of the Cerrado, little is known about its microbiome, with few publications describing some aspects of the bacterial and fungal communities found on this biome and almost no references about archaea. In this study, we describe the archaeal diversity in Cerrado sensu stricto soils, comparing the archaeal communities from soils of an area long protected from fires to one exposed to biennial fires, using both 16S rRNA and amoA genes as molecular markers. Almost all 16S rRNA sequences from both studied areas were affiliated with I.1b and 1.1c Thaumarchaeota, groups commonly detected in terrestrial environments. A higher relative abundance of I.1b thaumarchaeal subgroup was detected in the frequently burned area even though no statistically significant differences were observed in archaeal 16S rRNA richness and diversity between the investigated areas. Many ammonia-oxidizing archaea (AOA) are affiliated with this group, which is consistent with the higher amoA diversity and OTU numbers detected in the area periodically burned. Taken together, our results suggest that, although total archaeal community richness and diversity do not seem to greatly differ between the investigated conditions, alterations in wood cover and vegetation structure caused by frequent fires likely cause long-term effects in AOA diversity in Cerrado soils.

中文翻译：

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周期性大火对巴西Cerrado土壤上古细菌群落的长期影响。

塞拉多生物群落对应于巴西的广阔地区，被认为是生物多样性的热点。频繁发生的火灾是该生物群落的自然特征，并会影响植被的结构和组成。但是，持续的人为行为正在促使火灾频率和季节发生变化。尽管塞拉多（Cerrado）的生物多样性很高，但对其微生物组知之甚少，很少有出版物描述该生物群落中细菌和真菌群落的某些方面，几乎没有关于古细菌的参考。在这项研究中，我们描述了Cerrado sensu stricto土壤中的古细菌多样性，使用16S rRNA和amoA比较了长期受火保护的土壤和遭受两年生火的土壤中的古细菌群落。基因作为分子标记。来自两个研究区域的几乎所有16S rRNA序列均与陆地环境中常见的I.1b和1.1c Thaumarchaeota相关。即使在研究区域之间未发现古细菌16S rRNA的丰富度和多样性方面，在统计上也没有显着差异，但在经常燃烧的区域中，I.1b拟南芥亚组的相对丰度较高。许多氨氧化古细菌（AOA）都与该组有关，这与较高的amoA一致定期燃烧的区域中检测到的多样性和OTU数量。两者合计，我们的结果表明，尽管在所研究的条件之间古细菌群落的总丰富度和多样性似乎没有很大差异，但频繁生火引起的木材覆盖率和植被结构变化可能对塞拉多土壤的AOA多样性造成长期影响。