Cell wall integrity and immune signaling systems cooperatively mediate responses to cell wall damage in the model plant Arabidopsis .

CRK2 associates with and activates RBOHD to trigger MAMP-induced ROS production, revealing a regulatory mechanism for plant NADPH oxidases through phosphorylati

The walls surrounding the cells of all land-based plants provide mechanical support essential for growth and development as well as protection from adverse environmental conditions like biotic and abiotic stress. Composition and structure of plant cell walls can differ markedly between cell types, developmental stages and species. This implies that wall composition and structure are actively modified during biological processes and in response to specific functional requirements. Despite extensive research in the area, our understanding of the regulatory processes controlling active and adaptive modifications of cell wall composition and structure is still limited. One of these regulatory processes is the cell wall integrity maintenance mechanism, which monitors and maintains the functional integrity of the plant cell wall during development and interaction with environment. It is an important element in plant pathogen interaction and cell wall plasticity, which seems at least partially responsible for the limited success that targeted manipulation of cell wall metabolism has achieved so far. Here, we provide an overview of the cell wall polysaccharides forming the bulk of plant cell walls in both monocotyledonous and dicotyledonous plants and the effects their impairment can have. We summarize our current knowledge regarding the cell wall integrity maintenance mechanism and discuss that it could be responsible for several of the mutant phenotypes observed.

Plant cells can be distinguished from animal cells by their cell walls and high-turgor pressure. Although changes in turgor and the stiffness of cell walls seem coordinated, we know little about the mechanism responsible for coordination. Evidence has accumulated that plants, like yeast, have a dedicated cell wall integrity maintenance mechanism. It monitors the functional integrity of the wall and maintains integrity through adaptive responses induced by cell wall damage arising during growth, development, and interactions with the environment. These adaptive responses include osmosensitive induction of phytohormone production, defense responses, as well as changes in cell wall composition and structure. Here, we investigate how the cell wall integrity maintenance mechanism coordinates changes in cell wall stiffness and turgor in Arabidopsis thaliana. We show that the production of abscisic acid (ABA), the phytohormone-modulating turgor pressure, and responses to drought depend on the presence of a functional cell wall. We find that the cell wall integrity sensor THESEUS1 modulates mechanical properties of walls, turgor loss point, ABA biosynthesis, and ABA-controlled processes. We identify RECEPTOR-LIKE PROTEIN 12 as a component of cell wall integrity maintenance–controlling, cell wall damage–induced jasmonic acid (JA) production. We propose that THE1 is responsible for coordinating changes in turgor pressure and cell wall stiffness. Significance Plants need to constantly adapt to a changing environment. Adaptation includes responses to biotic and abiotic stress. Key elements determining the response to abiotic stress are the cell walls surrounding all plant cells and the phytohormone abscisic acid, which influence turgor pressure in plants. Turgor pressure in plant cells is much higher than in animal cells and a key driver of plant growth and development. Here, we investigate the mechanism regulating cell wall stiffness and coordinating changes in stiffness and turgor with abscisic acid production. We characterize key elements of the mechanism and dissect its mode of action. This knowledge will enable us to improve plant resistance to drought stress, which is necessary due to our changing environment.

The plant cell walls surrounding all plant cells are highly dynamic structures, which change their composition and organization in response to chemical and physical stimuli originating both in the environment and in plants themselves. They are intricately involved in all interactions between plants and their environment while also providing adaptive structural support during plant growth and development. A key mechanism contributing to these adaptive changes is the cell wall integrity (CWI) maintenance mechanism. It monitors and maintains the functional integrity of cell walls by initiating adaptive changes in cellular and cell wall metabolism. Despite its importance, both our understanding of its mode of action and knowledge regarding the molecular components that form it are limited. Intriguingly, the available evidence implicates mechanosensing in the mechanism. Here, we provide an overview of the knowledge available regarding the molecular mechanisms involved in and discuss how mechanoperception and signal transduction may contribute to plant CWI maintenance.