RT Journal Article SR Electronic T1 Expansin-controlled cell wall stiffness regulates root growth in Arabidopsis JF bioRxiv FD Cold Spring Harbor Laboratory SP 2020.06.25.170969 DO 10.1101/2020.06.25.170969 A1 Marketa Samalova A1 Kareem Elsayad A1 Alesia Melnikava A1 Alexis Peaucelle A1 Evelina Gahurova A1 Jaromir Gumulec A1 Ioannis Spyroglou A1 Elena V. Zemlyanskaya A1 Elena V. Ubogoeva A1 Jan Hejatko YR 2020 UL http://biorxiv.org/content/early/2020/07/31/2020.06.25.170969.abstract AB Expansins facilitate cell expansion via mediating pH-dependent cell wall (CW) loosening. However, the role of expansins in the control of biomechanical CW properties in the tissue and organ context remains elusive. We determined hormonal responsiveness and specificity of expression and localization of expansins predicted to be direct targets of cytokinin signalling. We found EXPA1 homogenously distributed throughout the CW of columella/ lateral root cap, while EXPA10 and EXPA14 localized predominantly at the three-cell boundaries of epidermis/cortex in various root zones. Cell type-specific localization of EXPA15 overlaps with higher CW stiffness measured via Brillouin light scattering microscopy. As indicated by both Brillouin frequency shift and AFM-measured Young’s modulus, EXPA1 overexpression upregulated CW stiffness, associated with shortening of the root apical meristem and root growth arrest. We propose that root growth in Arabidopsis requires delicate orchestration of biomechanical CW properties via tight regulation of various expansins’ localization to specific cell types and extracellular domains.Competing Interest StatementThe authors have declared no competing interest.