KATANIN and CLASP function at different spatial scales to mediate microtubule response to mechanical stress in Arabidopsis cotyledons

Mechanical stress influences cell-and tissue-scale processes across all kingdoms. It remains challenging to delineate how mechanical stress, originating at these different length scales, impacts cell and tissue form. We combine growth tracking of cells, quantitative image analysis, as well as molecular and mechanical perturbations to address this problem in pavement cells of Arabidopsis thaliana cotyledon tissue. We show that microtubule organization based on chemical signals and cell-shape-derived mechanical stress varies during early stages of pavement cell development and is mediated by the evolutionary conserved proteins, KATANIN and CLASP. However, we find that these proteins regulate microtubule organization in response to tissue-scale mechanical stress to different extents in the cotyledon epidermis. Our results further demonstrate that regulation of cotyledon form is uncoupled from the mechanical-stress-dependent control of pavement cell shape that relies on microtubule organization governed by subcellular mechanical stress.

Automated summary

This study investigates how mechanical stress influences cell and tissue form at different length scales in Arabidopsis thaliana cotyledon tissue. The researchers find that microtubule organization in pavement cells is mediated by chemical signals and cell-shape-derived mechanical stress during early development stages and regulated by KATANIN and CLASP proteins. However, the impact of these proteins on tissue-scale mechanical stress varies in the epidermis of cotyledons. Overall, the study shows that cotyledon form regulation is separate from the control of pavement cell shape mediated by microtubule organization under subcellular mechanical stress.