Abstract : Protein lysine acetylation is a highly conserved posttranslational modification that plays key roles in many biological processes such as the regulation of gene expression, chromatin dynamics, and metabolic pathways. Recent studies revealed that various pathogens use lysine acetylation to interfere with host immune responses. Identification of lysine-acetylated host proteins resulting from virulence activities of pathogen effectors is therefore essential for understanding their biological functions. Here we provide a method for immunoprecipitating lysine-acetylated proteins transiently expressed in planta under non-denaturing or denaturing conditions and detecting them by immunoblotting. To illustrate this rapid and simple procedure, immunoprecipitation of the lysine-acetylated WRKY domain of the RRS1-R immune receptor, a substrate of the Ralstonia solanacearum PopP2 effector, is presented as a typical example.