S17 - Session O1 - Apple firmness relies on cell wall architecture.

Authors: Marc Lahaye *, Mickael Delaire, Mathilde Orsel, Remi Bauduin

Apple, one of the major fleshy fruit commodities worldwide, offers divers texture qualities to consumers and food processors. Knowledge on the underlying structural determinants of textures is required to help developing pertinent varieties, production practice, post-harvest management and processing to fit with new environmental and societal constraints and thus, making full use of productions without waste. Cell wall polysaccharide and water compartmentalization are known key contributors of fruit texture. In cell wall, pectin has been highlighted as a major determinant of apple firmness 1 in relation with water compartmentalization and cell wall organization 2,3 . Cell wall remodeling occurring all along fruit development, the synthesis and metabolism of the glucomannan family of hemicellulose during the early cell wall set-up 4,5 will be presented as one possible determining step of the ripe fruit texture. New means of assessing cell wall architecture will be discussed along with apple texture variability. 1 Videcoq, et al. (2017). Examining the contribution of cell wall polysaccharides to the mechanical properties of apple parenchyma tissue using exogenous enzymes. J Exp Bot 68: 5137-5146. 2 Lahaye et al. (2018). Water and cell wall contributions to apple mechanical properties. Food Chem. 268: 386-394. 3 Lahaye et al. (2020). Cellulose, pectin and water in cell walls determine apple flesh viscoelastic mechanical properties. Carbohydr Polym 232: 115768. 4 Dheilly et al. (2016). Cell wall dynamics during apple development and storage involves hemicellulose modifications and related expressed genes. BMC Plant Biol. 16: 201 5 Lahaye et al. (2021). Comparison of cell wall chemical evolution during the development of fruits of two contrasting quality from two members of the Rosaceae family: Apple and sweet cherry. Plant Physiol Biochem 168: 93-104.