Abstract | Mechanical stress contributes to the expression of the STM homeobox gene in Arabidopsis shoot meristems

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Mechanical stress contributes to the expression of the STM homeobox gene in Arabidopsis shoot meristems

Abstract

Affiliation details

INRA, CNRS, ENS Lyon, UCB Lyon 1, Université de Lyon, France; CNRS, ENS Lyon, UCB Lyon 1, Université de Lyon, France; UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, France; Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Japan; Nara Institute of Science and Technology, Japan

The role of mechanical signals in cell identity determination remains poorly explored in tissues. Furthermore, because mechanical stress is widespread, mechanical signals are difficult to uncouple from biochemical-based transduction pathways. Here we focus on the homeobox gene SHOOT MERISTEMLESS (STM), a master regulator and marker of meristematic identity in Arabidopsis. We found that STM expression is quantitatively correlated to curvature in the saddle-shaped boundary domain of the shoot apical meristem. As tissue folding reflects the presence of mechanical stress, we test and demonstrate that STM expression is induced after micromechanical perturbations. We also show that STM expression in the boundary domain is required for organ separation. While STM expression correlates with auxin depletion in this domain, auxin distribution and STM expression can also be uncoupled. STM expression and boundary identity are thus strengthened through a synergy between auxin depletion and an auxin-independent mechanotransduction pathway at the shoot apical meristem.

DOI: http://dx.doi.org/10.7554/eLife.07811.001