Biology Department, The Johns Hopkins University, Baltimore, MD, USA.
Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA.
Environ Microbiol. 2016 Jun;18(6):2064-77. doi: 10.1111/1462-2920.13259. Epub 2016 Mar 21.
Halite endoliths in the Atacama Desert represent one of the most extreme ecosystems on Earth. Cultivation-independent methods were used to examine the functional adaptations of the microbial consortia inhabiting halite nodules. The community was dominated by haloarchaea and functional analysis attributed most of the autotrophic CO2 fixation to one unique cyanobacterium. The assembled 1.1 Mbp genome of a novel nanohaloarchaeon, Candidatus Nanopetramus SG9, revealed a photoheterotrophic life style and a low median isoelectric point (pI) for all predicted proteins, suggesting a 'salt-in' strategy for osmotic balance. Predicted proteins of the algae identified in the community also had pI distributions similar to 'salt-in' strategists. The Nanopetramus genome contained a unique CRISPR/Cas system with a spacer that matched a partial viral genome from the metagenome. A combination of reference-independent methods identified over 30 complete or near complete viral or proviral genomes with diverse genome structure, genome size, gene content and hosts. Putative hosts included Halobacteriaceae, Nanohaloarchaea and Cyanobacteria. Despite the dependence of the halite community on deliquescence for liquid water availability, this study exposed an ecosystem spanning three phylogenetic domains, containing a large diversity of viruses and predominance of a 'salt-in' strategy to balance the high osmotic pressure of the environment.
在阿塔卡马沙漠中，卤虫内生物代表了地球上最极端的生态系统之一。采用非培养方法研究了栖息在盐结瘤中的微生物群落的功能适应性。该群落主要由盐杆菌和功能分析归因于一种独特的蓝细菌进行大多数自养 CO2 固定。新型纳米盐杆菌的组装 1.1 Mbp 基因组，Candidatus Nanopetramus SG9，揭示了一种光异养生活方式和所有预测蛋白的低中位数等电点 (pI)，表明其为渗透平衡的“盐入”策略。群落中鉴定的藻类的预测蛋白也具有与“盐入”策略相似的 pI 分布。纳米盐杆菌基因组中含有一个独特的 CRISPR/Cas 系统，其间隔子与宏基因组中的部分病毒基因组匹配。参考独立方法组合鉴定出 30 多个完整或近乎完整的病毒或前病毒基因组，具有不同的基因组结构、基因组大小、基因组成和宿主。推定的宿主包括盐杆菌科、纳米盐杆菌和蓝细菌。尽管盐结瘤社区依赖潮解来获得液态水，但本研究揭示了一个跨越三个系统发育域的生态系统，其中包含大量不同的病毒和“盐入”策略的优势，以平衡环境的高渗透压。
