RT Journal Article
SR Electronic
T1 Root meristem shaping via brassinosteroid-controlled cell geometry
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2021.04.01.438011
DO 10.1101/2021.04.01.438011
A1 Y. Fridman
A1 S. Strauss
A1 G. Horev
A1 M. Ackerman-Lavert
A1 A Reiner Benaim
A1 B Lane
A1 R.S. Smith
A1 S. Savaldi-Goldstein
YR 2021
UL http://biorxiv.org/content/early/2021/04/02/2021.04.01.438011.abstract
AB Growth extent and direction determine cell and whole-organ architecture. How they are spatiotemporally modulated to control size and shape? Here we tackled this question by studying the effect of brassinosteroid (BR) signaling on the structure of the root meristem. Quantification of the 3D geometry of thousands of individual meristematic cells across different tissue types showed that modulation of BR signaling yields distinct changes in growth rate and anisotropy, which affects the time cells spend in the meristem and has a strong impact on final root form. By contrast, the hormone effect on cell volume was minor, establishing cell volume as invariant to the effect of BR. Thus, BR has highest effect on cell shape and growth anisotropy, regulating overall radial growth of the meristem, while maintaining a coherent distribution of cell sizes. Moving from single-cell quantification to the whole organ, we developed a computational model of radial growth that demonstrates how differential growth regulation by BR between the inner and outer tissues shapes the meristem. The model explains the unintuitive outcomes of tissue-specific perturbation of BR signaling and suggests that the inner and outer tissues have independent but coordinated roles in growth regulation.Competing Interest StatementThe authors have declared no competing interest.