Figure 3. FLYC1 mRNA localization in Venus flytrap trigger hairs.

(A) Toluidine blue-stained longitudinal section through the base of a trigger hair. Elongated sensory cells are visible at the indentation zone (arrowheads). (B) Max projection through a longitudinal section after fluorescent in situ hybridization. (Top) FLYC1 transcript (red) and DAPI (blue) at low (left) and high (right) magnification of the indentation zone. Note localization of the FLYC1 transcript puncta in sensory cells. (Bottom) No signal was observed when using FLYC1-sense probes. High background fluorescence is observed in all channels. (C) Toluidine blue-stained transverse section through the indentation zone. The cells forming the outer ring are presumed to be the mechanosensors (Benolken and Jacobson, 1970). (D) Max projection through a transverse section after fluorescent in situ hybridization. FLYC1 transcript (red) at low (left) and high (right) magnification. Note localization of the FLYC1 transcript puncta predominantly in the sensory cells of the indentation zone. (E) Max projection through a transverse section of the trigger hair lever. No transcript was observed. Scale bars, μm.

Figure 3—figure supplement 1. Autofluorescence and EF1α transcript expression in Venus flytrap.

(A) Unprocessed Venus flytrap trigger hair in different channels to depict autofluorescence from the plant cuticle. Images were taken with the same settings as tissue subjected to in situ hybridization. (B) A longitudinal section of a trigger hair and trap with smFISH against the housekeeping gene EF1α (green), FLYC1 (red), and DAPI (blue). White arrowheads indicate examples of EF1α expression in various cells throughout the tissue. Scale bar, µm.

Figure 3—figure supplement 2. FLYC2 and DmOSCA transcript expression in trigger hair.

Max projection through longitudinal sections after fluorescent in situ hybridization of (A) FLYC2 transcript and (B) DmOSCA transcript at low (left) and high resolution (center and right). FLYC2 and DmOSCA transcript is depicted in red channel and DAPI in blue. Note no transcript was observed for FLYC2, whereas DmOSCA was observed mostly in the sensory cells. Scale bars, µm.