Figure 4.

In situ identification and intracellular localization of ‘Candidatus Steffania adelgidicola' and ‘Candidatus Ecksteinia adelgidicola' in adults and eggs of A. nordmannianae/piceae. Bacterial symbionts were labeled by FISH using symbiont-specific 16S rRNA-targeted oligonucleotide probes together with a probe mix targeting all bacteria (Supplementary Table S1). Probes specific for the coccoid ‘Candidatus S. adelgidicola' were labeled with Cy3 (red); three probes specific for the polymorphic ‘Candidatus E. adelgidicola' were labeled with Cy5 (blue) and used simultaneously. Probes targeting all bacteria were labeled with FLUOS (green). The combined signal from bacterial and symbiont-specific probes appear yellow for ‘Candidatus S. adelgidicola' and blue–green for ‘Candidatus E. adelgidicola', respectively. (a) Bacteriocytes of an adult adelgid sampled in Gosau, Austria. (b) Both symbionts inside an adelgid egg. Bars represent 10 μm.