Fig. 1: Single cell imaging of flagellar wrapping motility in the gut sorting organ.

a Schematic illustration of a second instar nymph of R. pedestris fed with C. insecticola. b Midgut organization and the bacterial sorting organ (CR). Representative image from three independent experiments showing similar results. c Symbiont localization at the CR-M4B region. The images show the gut region 0, 2, and 4 h after feeding of GFP-labeled C. insecticola. Note the symbionts start entering the CR 2 h after feeding and are passing through the narrow duct 4 h after feeding. See also Movie S1. d Time required for symbiont sorting. Ratio of the locations where the GFP signal from C. insecticola was detected at the most distal part is shown (N = 30 nymphs). e Time course of symbiont displacement in the CR-M4B region 2–4 h after feeding of GFP-labeled C. insecticola. Single-cell movement colored by a blue line, and 15-cell displacements are overlayed. f Direct visualization of the flagellar filament of the symbiont in the M4B region. C. insecticola cells fluorescently labeled by amine-reactive dye were fed to a second instar nymph, and the gastrointestinal tract was dissected 2–4 h after infection. Left: Bright-field. Right: Fluorescent. Representative result from at least three independent experiments that yielded similar observations. See Movie S2. g Flagellar wrapping in the CR-M4B region. Yellow-boxed regions in (f) were magnified, and time-lapsed images are presented. Schematic are overlaid to indicate the cell body and flagellar filaments. Source data are provided with this paper.