Phylogenetic and Functional Substrate Specificity for Endolithic Microbial Communities in Hyper-Arid Environments
Phylogenetic and Functional Substrate Specificity for Endolithic Microbial Communities in Hyper-Arid Environments
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DOI：
10.3389/fmicb.2016.00301
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发表时间：
2016-03-09
影响因子：
5.2
通讯作者：
DiRuggiero, Jocelyne
中科院分区：
文献类型：
--
作者：
Crits-Christoph, Alexander;Robinson, Courtney K.;DiRuggiero, Jocelyne
在极度缺水的情况下，石内（岩石内部）微生物生态系统被认为是寒冷和炎热沙漠中生命的环境避难所，但它们的多样性和功能适应性仍有待探索。对方解石和熔结凝灰岩两种岩石基质的群落进行宏基因组分析，发现它们以蓝藻、放线菌和绿球藻为主。主要门的相对分布是显着不同的两个基板和生物多样性的估计，从16 S rRNA基因序列和宏基因组数据，都指向一个更高的分类多样性的方解石社区。虽然这两个内石器时代的社会表现出适应极端干旱和岩石栖息地，他们的功能能力显示出显着差异。ABC转运蛋白和途径的调节更多样化的方解石chasmoendolithic社区。相比之下，熔结凝灰岩隐石群落富含次生代谢产物，如非核糖体肽（NRP）和聚酮化合物（PK）。集合体的宏基因组数据产生的人口基因组的主要门中发现的两个社区，并揭示了更大的多样性的蓝藻种群基因组的方解石基板。在每个社区的优势蓝藻基因组草案构建超过93%的估计完整性。这两个注释的蛋白质组共享64%的氨基酸同一性，并且在来自熔结凝灰岩的基因组草案中发现了显著更高数量的参与铁更新的基因和NRPS基因簇。这两个社区范围内和基因组特异性的差异可能与较高的水的可用性和殖民化的大裂缝和裂缝中的方解石相比，殖民化的空间和营养资源的窄孔隙的熔结凝灰岩的严酷的竞争。总之，这些结果表明，可居住的建筑石基板chasmoendolithic与cryptoendolithic -可能是一个必不可少的元素，在确定的殖民化和多样性的微生物群落的石内基板在干极限的生活。
Under extreme water deficit, endolithic (inside rock) microbial ecosystems are considered environmental refuges for life in cold and hot deserts, yet their diversity and functional adaptations remain vastly unexplored. The metagenomic analyses of the communities from two rock substrates, calcite and ignimbrite, revealed that they were dominated by Cyanobacteria, Actinobacteria, and Chloroflexi. The relative distribution of major phyla was significantly different between the two substrates and biodiversity estimates, from 16S rRNA gene sequences and from the metagenomic data, all pointed to a higher taxonomic diversity in the calcite community. While both endolithic communities showed adaptations to extreme aridity and to the rock habitat, their functional capabilities revealed significant differences. ABC transporters and pathways for osmoregulation were more diverse in the calcite chasmoendolithic community. In contrast, the ignimbrite cryptoendolithic community was enriched in pathways for secondary metabolites, such as non-ribosomal peptides (NRP) and polyketides (PK). Assemblies of the metagenome data produced population genomes for the major phyla found in both communities and revealed a greater diversity of Cyanobacteria population genomes for the calcite substrate. Draft genomes of the dominant Cyanobacteria in each community were constructed with more than 93% estimated completeness. The two annotated proteomes shared 64% amino acid identity and a significantly higher number of genes involved in iron update, and NRPS gene clusters, were found in the draft genomes from the ignimbrite. Both the community-wide and genome-specific differences may be related to higher water availability and the colonization of large fissures and cracks in the calcite in contrast to a harsh competition for colonization space and nutrient resources in the narrow pores of the ignimbrite. Together, these results indicated that the habitable architecture of both lithic substrates-chasmoendolithic versus cryptoendolithic - might be an essential element in determining the colonization and the diversity of the microbial communities in endolithic substrates at the dry limit for life.