Abstract：
Candidate bacterial phylum Omnitrophota has not been isolated and is poorly understood. We analysed 72 newly sequenced and 349 existing Omnitrophota genomes representing 6 classes and 276 species, along with Earth Microbiome Project data to evaluate habitat, metabolic traits and lifestyles. We applied fluorescence-activated cell sorting and differential size filtration, and showed that most Omnitrophota are ultra-small (~0.2 μm) cells that are found in water, sediments and soils. Omnitrophota genomes in 6 classes are reduced, but maintain major biosynthetic and energy conservation pathways, including acetogenesis (with or without the Wood-Ljungdahl pathway) and diverse respirations. At least 64% of Omnitrophota genomes encode gene clusters typical of bacterial symbionts, suggesting host-associated lifestyles. We repurposed quantitative stable-isotope probing data from soils dominated by andesite, basalt or granite weathering and identified 3 families with high isotope uptake consistent with obligate bacterial predators. We propose that most Omnitrophota inhabit various ecosystems as predators or parasites.
摘要：
尚未分离出候选细菌Oomnitrophica，并且对其了解甚少。我们分析了72个新测序和349个现有的Omnitropha基因组，代表6类和276种，以及地球微生物组项目数据来评估栖息地，代谢特征和生活方式。我们应用了荧光激活细胞分选和差异大小过滤，并显示大多数Omnitropha是在水中发现的超小（〜0.2μm）细胞，沉积物和土壤。6类的Omnitropha基因组减少，但保持主要的生物合成和节能途径，包括乙酸生成（有或没有Wood-Ljungdahl途径）和不同的呼吸。至少64％的Omnitropha基因组编码典型的细菌共生体的基因簇，暗示与主人相关的生活方式。我们重新利用了以安山岩为主的土壤中的定量稳定同位素探测数据，玄武岩或花岗岩风化，并确定了3个具有高同位素吸收的科，与专性细菌捕食者一致。我们建议大多数Omnitropha作为捕食者或寄生虫栖息在各种生态系统中。
