Cell edges - from polarity to growth control

Abstract

A fundamental question in biology is how multicellular organisms robustly produce organ shapes. The underlying process of morphogenesis involves the integration of biochemical, genetic, and mechanical factors across multiple spatio-temporal scales. In plants, their fixed tissue topology dictates that adjacent cells must coordinate their growth patterns, which are in turn controlled by the mechanical properties of the cell wall. According to the leading paradigm in the field, patterned deposition of cellulose establishes anisotropic cell wall properties that determine directional growth. However, cells can also control cell wall properties independently of cellulose anisotropy, notably through modifying cell wall properties at cell edges (where two faces meet). My team has recently demonstrated that cell edges additionally act as a domain for the perception and integration of tissue-scale mechanical signals to promote robust morphogenesis. I will present our latest hypotheses regarding the mechanisms that establish cell edge polarity, how this polarity is used to control 3D growth, and why such mechanisms have evolved in the context of 3D organogenesis.

References

Elliott, Liam, et al. "A self-regulatory cell-wall-sensing module at cell edges controls plant growth." Nature Plants 10.3 (2024): 483-493.

Kirchhelle, Charlotte, et al. "Two mechanisms regulate directional cell growth in Arabidopsis lateral roots." Elife 8 (2019): e47988.

Kirchhelle, Charlotte, et al. "The specification of geometric edges by a plant Rab GTPase is an essential cell-patterning principle during organogenesis in Arabidopsis." Developmental Cell 36.4 (2016): 386-400.