Updated project metadata. Cellulose is the major polysaccharide in the primary and secondary cell wall. Its breakdown generates short-chain cellooligomers (COs) which induce Ca2+-dependent cell wall integrity (CWI) responses. Recently, a mutant (cork1) which did not respond to COs was identified. To find out the early phosphorylation events following CO perception, roots of the segregated wild-type and homozygous mutants (F2 generation from cork1-2 X AeqWT) were treated with 10 µM cellotriose or water for 0, 5 and 15 minutes. Phosphoproteome analyses identified early targets involved in signaling, the endoplasmatic recticulum/Golgi secretory pathway, cell wall repair and immune responses. The result identified protein targets of the novel CO-CORK1 pathway and shine light on the role of COs in CWI maintenance.