Hubert Jan, Glowska-Patyniak Eliza, Dowd Scot E, Klimov Pavel B
Department of Microbiology, Nutrition and Dietetics, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Prague, Czechia.
Department of Animal Morphology, Faculty of Biology, Adam Mickiewicz University in Poznan, Poznan, Poland.
mSystems. 2025 May 20;10(5):e0176924. doi: 10.1128/msystems.01769-24. Epub 2025 Apr 18.
We investigated the tripartite interactions between two intracellular bacterial symbionts, and in . Cultures of are typically single-infected by one intracellular symbiont. However, co-infection can be experimentally induced by mixing single-infected cultures, resulting in 10% of mite individuals being double-infected () and a corresponding reduction in host fitness. Here, we assembled the genomes of and and analyzed their gene expression in parental single-infected and mixed mite cultures using population-level samples (ranging from 7,500 to 10,000 mites). interacts more extensively with its mite host than in single-infected cultures. However, in mixed cultures, (i) exhibited reduced regulation of the host compared with ; (ii) the gene expression profile of shifted, increasing its interactions with the host, whereas the gene expression profile of remained unchanged; and (iii) genes exhibited a loss of interactions with mite gene expression, as indicated by reduced correlations (for example with host MAPK, endocytosis, and calcium signaling pathways). The experiments show that at the mite population level, symbiont infection disrupts gene expression interaction between the two symbionts and their host in different ways. was more influenced by gene expression than vice versa. can inhibit the growth of by disrupting its interaction with the host, leading to a loss of influence on mite immune and regulatory pathways. The reasons for responses are due to co-infection or the reduced frequency of single-infected individuals due to the analyses of population-level samples.
We found that disrupts the interaction between and mite host. In single-infected cultures, strong correlations exist between symbiont and host gene expressions. Interestingly, although can also interact with the host, this interaction appears weaker compared with in single-infected cultures. These results suggest that both symbionts affect mite host gene expression, particularly in immune and regulatory pathways. In mixed samples, appears to outcompete by disrupting its host interaction. It indicates competition between these two intracellular symbionts in mite populations. belongs to a mite-specific supergroup Q, distinct from the more commonly studied supergroups. As these mite-specific bacteria exhibit pathogen-blocking effects, our findings may have relevance for other systems, such as ticks and tick-borne diseases. The study sheds light on intracellular symbiont interaction within a novel mite-symbiont model.
我们研究了两种细胞内细菌共生体以及在[螨类名称]中的三方相互作用。[螨类名称]的培养物通常被一种细胞内共生体单一感染。然而，通过混合单一感染的培养物可实验性诱导共感染，导致10%的螨个体被双重感染（[具体感染情况]），并相应降低宿主适应性。在此，我们组装了[共生体名称1]和[共生体名称2]的基因组，并使用群体水平样本（7500至10000只螨）分析了它们在亲代单一感染和混合螨培养物中的基因表达。在单一感染培养物中，[共生体名称1]与其螨宿主的相互作用比[共生体名称2]更广泛。然而，在混合培养物中，（i）与[共生体名称2]相比，[共生体名称1]对宿主的调控作用减弱；（ii）[共生体名称1]的基因表达谱发生变化，增加了其与宿主的相互作用，而[共生体名称2]的基因表达谱保持不变；（iii）[共生体名称1]的基因与螨基因表达的相互作用减弱，表现为相关性降低（例如与宿主丝裂原活化蛋白激酶、内吞作用和钙信号通路）。实验表明，在螨群体水平上，共生体感染以不同方式破坏了两种共生体与其宿主之间的基因表达相互作用。[共生体名称1]比[共生体名称2]更受[共生体名称2]基因表达的影响。[共生体名称1]可通过破坏[共生体名称2]与宿主的相互作用来抑制其生长，导致[共生体名称2]对螨免疫和调控途径的影响丧失。这些反应的原因是由于共感染或由于群体水平样本分析导致单一感染[共生体名称2]个体的频率降低。
我们发现[共生体名称1]破坏了[共生体名称2]与螨宿主之间的相互作用。在单一感染[共生体名称2]的培养物中，共生体与宿主基因表达之间存在强相关性。有趣的是，尽管[共生体名称1]也能与宿主相互作用，但与单一感染培养物中的[共生体名称2]相比，这种相互作用似乎较弱。这些结果表明，两种共生体均影响螨宿主基因表达，特别是在免疫和调控途径中。在混合样本中，[共生体名称1]似乎通过破坏[共生体名称2]与宿主的相互作用而胜过[共生体名称2]。这表明这两种细胞内共生体在螨群体中存在竞争。[共生体名称1]属于螨特异性超群Q，不同于更常研究的[其他超群名称]超群。由于这些螨特异性细菌具有病原体阻断作用，我们的发现可能与其他系统相关，如蜱和蜱传疾病。该研究揭示了新型螨 - 共生体模型中细胞内共生体的相互作用。
