Spatio-temporal orientation of microtubules controls conical cell shape in Arabidopsis thaliana petals

• DOI: 10.1371/journal.pgen.1006851
• Publication Date: 2017-06-23T17:35:45Z
• Authors: Huibo Ren; Xie Dang; Xianzhi Cai; Peihang Yu; Yajun Li; Shanshan Zhang; Menghong Liu; Binqing Chen; Deshu Lin
• Keywords: Live cell imaging; Petal; Epidermis (zoology); Genetic screen; Plant cell

The physiological functions of epidermal cells are largely determined by their diverse morphologies. Most flowering plants have special conical-shaped petal that thought to influence light capture and reflectance, provide pollinator grips, but the molecular mechanisms controlling conical cell shape remain unknown. Here, we developed a live-confocal imaging approach quantify geometric parameters in Arabidopsis thaliana (A. thaliana). Through genetic screens, identified katanin (KTN1) mutants showing phenotype decreased tip sharpening cells. Furthermore, demonstrated SPIKE1 Rho Plants (ROP) GTPases were required for final formation cells, as KTN1 does. Live-cell showed wild-type exhibited random orientation cortical microtubule arrays at early developmental stages displayed well-ordered circumferential later stages. By contrast, loss prevented networks from shifting into arrays. We further filamentous actin cap, which is typical feature several plant types including root hairs leaf trichomes, was not observed growth apexes during development. Moreover, our pharmacological data suggested microtubules shaping. Together, results novel studying morphogenesis suggest spatio-temporal organization plays crucial roles shape.