ABSTRACT

Interactions among endosymbiotic bacteria inside their eukaryotic hosts are poorly understood, particularly in mites. The mite Tyrophagus putrescentiae is a common, medically important generalist species that has many intracellular and gut bacterial symbionts. In the experiments, we examined bacterial abundances and composition in mite populations obtained by controlled mixing of stock mite populations that differed in the presence/absence of the major intracellular bacteria Wolbachia and Cardinium. Changes in microbial communities were characterized using 16S ribosomal RNA high-throughput sequencing (pooled mite individuals) and quantitative PCR for key microbial taxa (individual mites). Mite fitness was estimated as a parameter of population growth. We detected that in mixed mite populations, Cardinium and Wolbachia can co-occur in the same mite individual. The presence of Cardinium was negatively correlated with the presence of Wolbachia and Bartonella, while the Bartonella and Wolbachia were positively correlated in individual level samples. Since mixed populations had lower abundances of Wolbachia, while the abundance of Cardinium did not change, we suggest that the presence of Cardinium inhibits the growth of Wolbachia. The mixed mite populations had lower population growth than parental populations. The possible effect of symbionts on the fitness of mixed population is discussed.

中文翻译：

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Cardinium 抑制其螨宿主 Tyrophagus putrescentiae 中的 Wolbachia，并影响宿主健康

摘要

人们对真核宿主内内共生细菌之间的相互作用知之甚少，尤其是在螨类中。螨腐食酪螨是一种常见的，医学上重要的通才物种有许多细胞内和肠道共生细菌。在实验中，我们检查了通过受控混合原种螨种群获得的螨种群中的细菌丰度和组成，这些种群在主要细胞内细菌Wolbachia和Cardinium的存在/不存在方面存在差异. 使用 16S 核糖体 RNA 高通量测序（汇集螨个体）和关键微生物分类群（个体螨）的定量 PCR 表征微生物群落的变化。螨适应度被估计为种群增长的参数。我们检测到在混合螨种群中，Cardinium和Wolbachia可以在同一螨个体中同时发生。的存在Cardinium呈负的存在相关的Wolbachia和巴尔通体，而巴尔通体和沃尔巴克氏体个体水平样本中呈正相关。由于混合种群的Wolbachia丰度较低，虽然Cardinium的丰度没有改变，但我们认为Cardinium的存在抑制了Wolbachia的生长。混合螨种群的种群增长率低于亲本种群。讨论了共生体对混合种群适应性的可能影响。