Some phytopathogenic bacteria produce an effector protein that inhibits exocytosis by affecting the proper assembly of the exocyst complex.
Under normal conditions (A), the exocyst complex is properly assembled to transfer the secretory vesicles to the cell membrane for the secretion their content into the apoplast.
When the cell is infected by the bacterium Xanthomonas (B), an effector protein blocks the proper assembly of the exocyst complex, thereby inhibiting the process of extracellular secretion.