The development of bio-control has become a major challenge in agriculture. We have recently characterised that the mutation of the PECTIN METHYL ESTERASE 17 in Arabidopsis ecotype Wassilewskija confers resistance to numerous biotic and abiotic stresses. Our preliminary results suggest that it overproduces phosphorylated polyols potentially derived from the cleavage of membrane lipids and phosphorylated oligosaccharides. In this context, we propose to characterise the role of these newly identified and accumulated carbohydrates in Arabidopsis thaliana mutants able to better adapt to changing environmental conditions. Three axes are developed: (i) a phenotypic characterisation of pme17 in the face of a wide range of stresses, (ii) a detailed characterisation of the carbohydrates produced and the determination of their role in triggering pme17 adaptation mechanisms in the face of these stresses, and (iii) finally the characterisation of a new receptor involved in the regulation of signal transduction. This project should lead to the identification of potential new stimulators of adaptation and plant defences (SDP).