Developing a 'thick skin': a paradoxical role for mechanical tension in maintaining epidermal integrity?

Roberta Galletti,Gwyneth C. Ingram,Stéphane Verger,Olivier Hamant

doi:10.1242/dev.132837

Abstract

Plant aerial epidermal tissues, like animal epithelia, act as load-bearing layers and hence play pivotal roles in development. The presence of tension in the epidermis has morphogenetic implications for organ shapes but it also constantly threatens the integrity of this tissue. Here, we explore the multi-scale relationship between tension and cell adhesion in the plant epidermis, and we examine how tensile stress perception may act as a regulatory input to preserve epidermal tissue integrity and thus normal morphogenesis. From this, we identify parallels between plant epidermal and animal epithelial tissues and highlight a list of unexplored questions for future research.

Highlights

Growth and morphogenesis are orchestrated by a bewildering range of signals
In this Review, we highlight how the epidermis covering the aerial parts of plants, and the epithelia lining the surfaces of animal tissues and organs, are functionally strikingly similar, yet molecularly largely distinct, and we explore the idea that they play analogous developmental roles in response to mechanical stress
Pectic polysaccharides are found throughout primary cell walls but, interestingly, specific pectin types tend to accumulate at the locations of highest predicted mechanical stress, such as at the outer epidermal cell junction, during organ expansion (Jarvis, 1998; Willats et al, 2001)

Summary

Introduction

Growth and morphogenesis are orchestrated by a bewildering range of signals. The interpretation of these signals provides cells with information about the general developmental and physiological state of the tissues that they are embedded in. In many species, root epidermal cells are lost during root maturation and replaced by so-called ‘peridermal tissues’ in a process similar to bark formation on tree trunks In this Review, we highlight how the epidermis covering the aerial parts of plants, and the epithelia lining the surfaces of animal tissues and organs, are functionally strikingly similar, yet molecularly largely distinct, and we explore the idea that they play analogous developmental roles in response to mechanical stress. Consistent with this key role, the loss of integrity, and of cell polarity and cell-to-cell adhesion, in both

C Molecular players

Conclusion