Analysis of the tripartite interactions between two bacterial symbionts, a novel <i>Solitalea</i> -like bacterium (Bacteroidota) and <i>Cardinium</i> , and the stored product mite <i>Tyrophagus putrescentiae</i> based on gene expression data

Here, we describe the novel Bacteroidetes symbiont (SOL) of mites. The analysis of gene expression in meta-transcriptomic samples from cultures with and without the intracellular parasite <i>Cardinium</i> revealed the effect of <i>Cardinium</i> on SOL as a model facultative symbiont of mites. Our findings suggest that there is competition between these two symbionts for nutrients. In addition, <i>Cardinium</i> can influence other bacterial symbionts via mite host immunity-related and regulatory pathways. <i>Tyrophagus putrescentiae</i> is a cosmopolitan pest mite that contaminates the home environment, including stored food and feed, with allergens. The interactions between intracellular bacteria and other members of the microbiome influence host physiology and indirectly affect allergen production.