PMC

A model depicting the molecular basis of ROS-dependent microtubule orientation and conical cell tip sharpening. We propose that AN and KTN1 jointly function to modulate microtubule orientation and conical cell shaping. AN functions to suppress ROS production, respectively. Both increased and decreased ROS suppress microtubule orientation into well-ordered circumferential arrays. We hypothesized that mechanical forces could generate a signal to induce microtubule orientation, and that conical cells could respond to mechanical cues generated by cell geometry, providing a feedback loop.

Distance function model of conical surface.

(A) Schematic of the conical frustum morphing with radial groove patterns. The grooves have a fixed width and varied gaps at different radial locations. The angle of the annulus sector is θ_a. (B) Simulated bending curvatures of pasta strips with varying gaps (g is from 1.5 to 6.5 mm) and fixed width (w = 1 mm). (C) Simulated snapshots of the conical frustum configurations of PDMS at different times, formed by the annulus section. (D) Simulated and theoretical heights of the conical frustum of PDMS as a function of time. The dotted data were measured from simulations. (E) Morphing of a section of the conical frustum from a cut annulus sector, where the outer boundary is defined by circle passing points (0, 36), (24, 0), and (−24, 0). (F) Morphing of a conical frustum from the uncut annulus sector. The color bar represents the out-of-plane displacement (unit: millimeters) in (C), (E), and (F).

Effect of SlMixta-like on the Formation of Conical Cells in Tomato.
(A) SEM micrograph of conical cells in petals of a MoneyMaker plant.
(B) SEM micrograph of conical cells in petals of the Slmixta-like ko line no. 1, showing a flatter shape.
(C) SEM micrograph of conical cells in petals of a SlMixta-like OE plant, showing more elongated and pointed shape.
(D) SEM micrograph of the conical cells in the epidermis of a mature green fruit of a MoneyMaker plant.
(E) SEM micrograph of the conical cells in the epidermis of a mature green fruit of the SlMixta-like KO line no. 1, showing much flatter cells. Scale bars are shown for each micrograph.
(F) SEM micrograph of the epidermis of a mature green fruit of the Slmixta-like ko line no. 1.
(G) Close-up view of protuberances on the surface of mature green fruits of the Slmixta-like ko line no. 1.
(F) and (G) Black semicircles indicate multicellular protuberances.
(A) to (G) Scale bars are shown in each micrograph.