Fig. 1: Profftella and tubes observed via optical microscopy and 2D TEM.

A Isolated Profftella cells observed under an DIC microscope. B, C Tubes in ruptured but unfixed Profftella observed by TEM. D–F TEM observation of ultrathin sections of chemically fixed and resin-embedded Profftella cells and tubes. Numerous Profftella cells are packed in a syncytium of the D. citri bacteriome (D). Longitudinal view of a tube (E). Cross-sectional view of the tubes (F). p, Profftella; t, tube; cm, cell membrane of Profftella; hco, host cell organelles. Scale bars: (A) 10 μm, (B) 2 μm; (C, E and F) 200 nm, (D) 1 μm.