CNRS, Sorbonne Université, Laboratoire d'Océanographie Microbienne, LOMIC, F-66650, Banyuls/mer, France.
University of Vienna, Department of Functional and Evolutionary Ecology, A-1090, Vienna, Austria.
ISME J. 2021 Oct;15(10):2933-2946. doi: 10.1038/s41396-021-00973-3. Epub 2021 May 3.
Marine microbes are major drivers of all elemental cycles. The processing of organic carbon by heterotrophic prokaryotes is tightly coupled to the availability of the trace element iron in large regions of the Southern Ocean. However, the functional diversity in iron and carbon metabolism within diverse communities remains a major unresolved issue. Using novel Southern Ocean meta-omics resources including 133 metagenome-assembled genomes (MAGs), we show a mosaic of taxonomy-specific ecological strategies in naturally iron-fertilized and high nutrient low chlorophyll (HNLC) waters. Taxonomic profiling revealed apparent community shifts across contrasting nutrient regimes. Community-level and genome-resolved metatranscriptomics evidenced a moderate association between taxonomic affiliations and iron and carbon-related functional roles. Diverse ecological strategies emerged when considering the central metabolic pathways of individual MAGs. Closely related lineages appear to adapt to distinct ecological niches, based on their distribution and gene regulation patterns. Our in-depth observations emphasize the complex interplay between the genetic repertoire of individual taxa and their environment and how this shapes prokaryotic responses to iron and organic carbon availability in the Southern Ocean.
海洋微生物是所有元素循环的主要驱动者。在南大洋的大部分地区，异养原核生物对有机碳的处理与痕量元素铁的供应密切相关。然而，不同群落中铁和碳代谢的功能多样性仍然是一个主要的未解决问题。利用包括 133 个宏基因组组装基因组（MAG）在内的新型南大洋宏基因组学资源，我们展示了在自然铁施肥和高营养低叶绿素（HNLC）水域中具有分类特异性生态策略的镶嵌体。分类分析显示，在不同的营养条件下，群落发生了明显的变化。群落水平和基因组解析的宏转录组学表明，分类归属与铁和碳相关功能角色之间存在中等相关性。当考虑单个 MAG 的中心代谢途径时，出现了多样化的生态策略。基于分布和基因调控模式，密切相关的谱系似乎适应了不同的生态位。我们的深入观察强调了个别分类群的遗传组成与其环境之间的复杂相互作用，以及这如何塑造了海洋原核生物对南大洋铁和有机碳供应的反应。
