Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems (BASE), Santiago, Chile.
Department of Ecological Sciences, Faculty of Sciences, University of Chile, Santiago, Chile.
Microbiol Spectr. 2024 Apr 2;12(4):e0383023. doi: 10.1128/spectrum.03830-23. Epub 2024 Mar 5.
Understanding the factors that sculpt fish gut microbiome is challenging, especially in natural populations characterized by high environmental and host genomic complexity. However, closely related hosts are valuable models for deciphering the contribution of host evolutionary history to microbiome assembly, through the underscoring of phylosymbiosis and co-phylogeny patterns. Here, we propose that the recent diversification of several species across the Southern Ocean would allow the detection of robust phylogenetic congruence between the host and its microbiome. We characterized the gut mucosa microbiome of 77 individuals from four field-collected species of the plunderfish (Teleostei, Notothenioidei), distributed across three biogeographic regions of the Southern Ocean. We found that seawater physicochemical properties, host phylogeny, and geography collectively explained 35% of the variation in bacterial community composition in gut mucosa. The core microbiome of spp. gut mucosa was characterized by a low diversity, mostly driven by selective processes, and dominated by a single Operational Taxonomic Unit (OTU) detected in more than 80% of the individuals. Nearly half of the core microbiome taxa, including , harbored co-phylogeny signal at microdiversity resolution with host phylogeny, indicating an intimate symbiotic relationship and a shared evolutionary history with . The clear phylosymbiosis and co-phylogeny signals underscore the relevance of the model in understanding the role of fish evolutionary history in shaping the gut microbiome assembly. We propose that the recent diversification of may have led to the diversification of , exhibiting patterns that mirror the host phylogeny.
Although challenging to detect in wild populations, phylogenetic congruence between marine fish and its microbiome is critical, as it highlights intimate associations between hosts and ecologically relevant microbial symbionts. Our study leverages a natural system of closely related fish species in the Southern Ocean to unveil new insights into the contribution of host evolutionary trajectory on gut microbiome assembly, an underappreciated driver of the global marine fish holobiont. Notably, we unveiled striking evidence of co-diversification between and its microbiome, demonstrating both phylosymbiosis of gut bacterial communities and co-phylogeny of some specific bacterial symbionts, mirroring the host diversification patterns. Given 's significance as a trophic resource in coastal areas and its vulnerability to climatic and anthropic pressures, understanding the potential evolutionary interdependence between the hosts and its microbiome provides valuable microbial candidates for future monitoring, as they may play a pivotal role in host species acclimatization to a rapidly changing environment.
理解鱼类肠道微生物组形成的因素具有挑战性，尤其是在具有高度环境和宿主基因组复杂性的自然种群中。然而，密切相关的宿主是破译宿主进化历史对微生物组组装贡献的有价值的模型，通过强调系统发育共生和共同进化模式。在这里，我们提出，在南大洋的几个物种的最近多样化将允许在宿主与其微生物组之间检测到稳健的系统发育一致性。我们描述了在南大洋三个生物地理区域采集的四个掠夺性鱼物种（Teleostei，Notothenioidei）的 77 个个体的肠道粘膜微生物组。我们发现，海水物理化学性质、宿主系统发育和地理共同解释了 肠道粘膜细菌群落组成变化的 35%。 spp. 肠道粘膜的核心微生物组的多样性低，主要由选择过程驱动，并且由在超过 80%的个体中检测到的单个操作分类单元 (OTU) 主导。核心微生物组的近一半分类群，包括 ，在微多样性分辨率下与宿主系统发育具有共进化信号，表明与宿主之间存在密切的共生关系和共同的进化历史。清晰的系统发育共生和共进化信号强调了 模型在理解鱼类进化历史在塑造肠道微生物组组装中的作用的相关性。我们提出， 的最近多样化可能导致了 的多样化，表现出与宿主系统发育相呼应的模式。
尽管在野生种群中难以检测到，但海洋鱼类与其微生物组之间的系统发育一致性至关重要，因为它突出了宿主与生态相关微生物共生体之间的密切联系。我们的研究利用南大洋中密切相关的鱼类物种的自然系统，揭示了宿主进化轨迹对肠道微生物组组装的贡献的新见解，这是全球海洋鱼类整体的一个未被充分认识的驱动因素。值得注意的是，我们揭示了 和其微生物组之间惊人的共同多样化证据，证明了肠道细菌群落的系统发育共生和一些特定细菌共生体的共进化，与宿主多样化模式相呼应。鉴于 在沿海地区作为营养资源的重要性及其对气候和人为压力的脆弱性，了解宿主与其微生物组之间的潜在进化相互依存关系提供了有价值的微生物候选者，用于未来的监测，因为它们可能在宿主物种适应快速变化的环境方面发挥关键作用。
