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BP: Fachverband Biologische Physik

BP 18: Cell mechanics II

BP 18.6: Vortrag

Mittwoch, 3. April 2019, 16:15–16:30, H10

How the cytoskeleton and cell shape directs pollen tube outgrowth in Arabidopsis thaliana — Lucie Riglet¹, •Karin John², Frédérique Rozier¹, Thierry Gaude¹, Catherine Quilliet², and Isabelle Fobis-Loisy¹ — ¹RDP, ENS Lyon, France — ²LIPhy, CNRS, U. Grenoble-Alpes, France

In the flowering plant Arabidopsis thaliana, the pollen tube that transports male gametes grows within the cell wall of the epidermal cells of the female reproductive organ, also named stigmatic papilla. In the katanin mutant (ktn), the shape of the papilla is slightly altered and cortical microtubules (CMT) are completely disorganized compared to the wild type. At the same time the directionality of pollen tube growth is disturbed. We show by Atomic Force Microscopy and measurements of pollen tube growth speed, that alterations in the CMT organization affect the mechanical properties of the stigmatic cell wall, which could be responsible for the disoriented pollen tube growth. We propose a simple model mechanism, where pollen outgrowth is directed by two basic principles: (i) minimizing locally the curvature of the pollen tube path on the papilla surface and (ii) mechanical anisotropy of the papilla wall stiffness.