In their natural environments, plants are under continuous biotic stress caused by different attackers and exposed to abiotic stresses that compromise their survival and offspring. Being well defended against environmental threats throughout the constitutive expression of defensive mechanisms may not always be the best strategy for plants due to the tradeoffs associated to such responses. One of these defensive mechanisms is constituted by the cell wall, a very dynamic and complex structure that is essential to protect plant cells against external threats and also regulates plant growth and development. The functional integrity of the wall during plant development and plant interaction with the environment might be monitored and maintained by a Cell Wall Integrity (CWI or WALLIN) system. In yeast, CWI initiates changes in the cell wall structure and in cellular metabolism to actively maintain functional wall integrity in response to cell wall damage (CWD). Several evidences shows that a dedicated plant CWI maintenance mechanism exists, that integrate many different sources of signalling into one overreaching signalling system (SignWALLINg). The data available suggest that modulation of CWI by cell wall remodelling might be an efficient strategy to improve plant resistance to environmental threats and to obtain crops varieties with improved broad-spectrum resistance to both biotic and abiotic stresses. This proposal aims to enhance our understanding of the fundamental functions of plant cell wall and CWI in the regulation of plant responses to environmental stresses and in particular in the modulation of plant innate immunity. Execution of this proposal will highlight Europe´s ability to address many unanswered questions about the contribution of the cell wall to plant-disease-resistance regulation, and will open novel avenues to study the potential to remodel the plant cell wall to uncouple plant resistance from tradeoffs.