Weisse Louis, Martin Lucile, Moumen Bouziane, Héchard Yann, Delafont Vincent
Laboratoire Écologie and Biologie des Interactions, UMR CNRS 7267, Université de Poitiers, , Poitiers, Nouvelle-Aquitaine, France.
mSystems. 2025 Jun 17;10(6):e0026125. doi: 10.1128/msystems.00261-25. Epub 2025 May 28.
. Babelota is a phylum of strictly intracellular bacteria whose representatives are commonly detected in various environments through metagenomics, though their presence, ecology, and biology have never been addressed so far. As a group of strict intracellular, we hypothesize that their presence, occurrence, and abundance heavily depend on their hosts, which are known as heterotrophic protists, based on few described isolates. Here, we conducted a sampling campaign allowing to characterize protists and associated bacterial communities, using high-throughput sequencing. In parallel, a systematic enrichment of protists from samples was performed to attempt characterization and isolation of new . Babelota within native hosts. We found that . Babelota are among the most widespread phylum among the rare ones. Protist enrichments are allowed in certain cases to enrich as well for . Babelota, which could be visualized infecting protist cells. Though cosmopolitan, . Babelota diversity was highly site-specific. Cooccurrence analyses allowed to retrieve well-known as well as new putative associations involving numerous protists of various trophic regimes. The combination of approaches developed in this study enhances our understanding of . Babelota ecology and biology, while paving the way for future isolation of new members of this elusive phylum, which could have huge impact on protists-and ecosystems-functioning.IMPORTANCEOur understanding of microbial diversity surrounding us and colonizing the environment has been dramatically impacted by the advent of DNA-based analyses. Such progress helped shine a new light on numerous lineages of yet-to-be-characterized microbes, whose ecology and biology are basically unknown. Among those uncharacterized clades is the Babelota, a bacterial phylum for which parasitism seems to be an ancestral trait. All known Babelota thrive by infecting phagotrophic protist hosts, thereby impacting this basal link of the trophic chain. The Babelota constitutes a model that stands out, as phylum-wide conserved parasitism has only been described in one previous occurrence for Bacteria, with the Chlamydiota. Thus, exploring the intricate interplay between Babelota and their protist hosts will advance our knowledge of bacterial diversity, their ecology, and global impact on ecosystem functioning.
巴氏菌门是一类严格的细胞内细菌，通过宏基因组学在各种环境中普遍检测到其代表菌株，但其存在、生态和生物学特性至今尚未得到研究。作为一组严格的细胞内细菌，基于少数已描述的分离株，我们推测它们的存在、出现和丰度在很大程度上依赖于它们的宿主，即异养原生生物。在这里，我们开展了一项采样活动，利用高通量测序对原生生物及其相关细菌群落进行表征。同时，对样本中的原生生物进行系统富集，以尝试在天然宿主中表征和分离新的巴氏菌。我们发现，巴氏菌是稀有门类中分布最广泛的门类之一。在某些情况下，原生生物富集也能富集巴氏菌，并且可以观察到巴氏菌感染原生生物细胞。尽管巴氏菌分布广泛，但其多样性具有高度的位点特异性。共现分析使我们能够发现涉及各种营养类型原生生物的已知以及新的假定关联。本研究中开发的方法相结合，增强了我们对巴氏菌生态和生物学的理解，同时为未来分离这个难以捉摸的门类的新成员铺平了道路，这可能对原生生物和生态系统功能产生巨大影响。
基于DNA的分析方法的出现极大地影响了我们对周围微生物多样性以及环境中定殖微生物的理解。这一进展有助于为众多尚未表征的微生物谱系带来新的认识，其生态和生物学特性基本未知。在这些未表征的进化枝中，巴氏菌门是一个细菌门类，寄生似乎是其祖先特征。所有已知的巴氏菌通过感染吞噬性原生生物宿主而生存，从而影响营养链的这一基础环节。巴氏菌门是一个突出的模型，因为全门类保守的寄生现象此前仅在细菌中的衣原体门有过描述。因此，探索巴氏菌与其原生生物宿主之间复杂的相互作用将推进我们对细菌多样性、其生态学以及对生态系统功能的全球影响的认识。
