Effector protein that plays different roles depending on the species and plant cultivars that interact with the pathogen. Acts as a virulence determinant by enhancing the development of disease symptoms and bacterial growth. Acts as an avirulence factor by eliciting hypersensitive response (HR) and plant resistance (By similarity). Secreted via type III secretion system (TTSS). Transcriptionally induced by HrpL. Belongs to the HopAB family.