Figure 4

Localization of horizontally-transmitted Gfp Asaia in organs of S. titanus individuals. Images of insect tissues after hybridization with the Cy3-labeled Asaia-specific probes (magenta) and the Cy5.5-labeled probes specific for the gfp gene (yellow) showing the distribution of the symbiont within the gut, the ovaries and testes of specimens after acquisition of the tagged bacterium via co-feeding or venereal transmission. A-C) Midgut portion of an individual after 48-hour acquisition during the co-feeding trial, observed by interferential contrast microscopy (A) and CLSM after hybridization with the Cy3-tagged probes targeting the whole Asaia population (B), or with the Cy5.5-marked probes specific for the gfp gene(C). D-F) Testis portion of an individual after co-feeding trial observed by interferential contrast microscopy (D), and by CLSM after hybridization with the Cy3-tagged probes targeting the whole Asaia population (E) and the Cy5.5-marked probes specific for the gfp gene (F). In G-I) ovaries of a S. titanus individual after the acquisition in venereal transmission experiments are shown. G) Interferential contrast micrograph showing a group of ovarioles. H, I) CLSM images of FISH with the Cy3-tagged probes targeting the whole Asaia population (H) and the Cy5.5-marked probes specific for the gfp gene (I). Bars = 150 µm.