Actin-mediated avoidance of tricellular junction influences global topology at the Arabidopsis shoot apical meristem

Yang Wang; Soeren Strauss; Richard S Smith; Arun Sampathkumar

doi:10.1016/j.celrep.2024.114844

Actin-mediated avoidance of tricellular junction influences global topology at the Arabidopsis shoot apical meristem

Cell Rep. 2024 Oct 16;43(11):114844. doi: 10.1016/j.celrep.2024.114844. Online ahead of print.

Authors

Yang Wang¹, Soeren Strauss², Richard S Smith³, Arun Sampathkumar⁴

Affiliations

¹ Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam, Germany; Department of Plant and Environmental Science, University of Copenhagen, Thorvaldsensvej 40, 1871 Copenhagen, Denmark.
² Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany.
³ Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany; Department of Computational and Systems Biology, John Innes Centre, Norwich Research Park, Colney Ln, NR4 7UH Norwich, UK.
⁴ Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam, Germany. Electronic address: sampathkumar@mpimp-golm.mpg.de.

PMID: 39418163
DOI: 10.1016/j.celrep.2024.114844

Abstract

Division plane orientation contributes to cell shape and topological organization, playing a key role in morphogenesis, but the precise physical and molecular mechanism influencing these processes remains largely obscure in plants. In particular, it is less clear how the placement of the new walls occurs in relation to the walls of neighboring cells. Here, we show that genetic perturbation of the actin cytoskeleton results in more rectangular cell shapes and higher incidences of four-way junctions, perturbing the global topology of cells in the shoot apical meristem of Arabidopsis thaliana. Actin mutants also exhibit changes in the expansion rate of the new versus the maternal cell wall after division, affecting the evolution of internal angles at tricellular junctions. Further, the increased width of the preprophase band in the actin mutant contributes to inaccuracy in the placement of the new cell wall. Computational simulation further substantiates this hypothesis and reproduces the observed cell shape defects.

Keywords: Arabidopsis; CP: Cell biology; CP: Plants; actin; cell division; cell packing; four-way junction; microtubules; shoot apical meristem; topology.