Rastogi, L.; Hussain, M.-M.; Tyagi, S.; Kabyashree, K.; Kharbanda, N.; Maiti, T. K.; Krishnan, V.; Jha, G.; Voxeur, A.; Pawar, P. A.-M.

O-acetylation is a crucial substitution found in hemicelluloses and pectin which are necessary for maintaining the flexibility and structural integrity of the cell. A balanced polysaccharide O-acetylation level is maintained by cell wall acetyl transferases and esterases present in different cell organelles. Specifically, the role of esterases in cell wall acetylation metabolism is less explored. Therefore, we investigated the role of AtGELP53 from the GELP family of esterases or lipases. Here, we show that AtGELP53 is localized in the plasma membrane. Analysis of AtGELP53 overexpressing independent transgenic lines revealed a decrease in xyloglucan acetylation, changes in other polysaccharide acetylation and alteration in cell wall composition. The series of elicitor-based, transcriptomic and proteomic analyses in AtGELP53 overexpressing lines suggested that oligosaccharide-mediated signalling activates the cell wall and defence-related genes primarily because of xyloglucan deacetylation. Furthermore, AtGELP53 overexpression plants showed resistance against Pseudomonas syringae and Ralstonia solanacearum through activation of elicitor-mediated defense response. Overall, our findings outline the role of AtGELP53 in polysaccharide acetylation, cell wall remodelling and defense through the activation of plant cell wall integrity.