Western blotting showing the regulation and secretion of PopW in Ralstonia solanacearum ZJ3721. An anti‐PopW polyclonal antibody was used to identify the presence of PopW in preparations from different sources. The cell‐free lysate preparations (CLPs) and concentrated supernatant preparations (CSPs) correspond to the odd and even numbers, respectively. ‘popW,’‘WT,’‘hrpB’ and ‘hrpV’ denote CLPs and CSPs of popW mutant ZJ3722 (lanes 1 and 2), wild‐type strain ZJ3721 (lanes 3 and 4), hrpB mutant ZJ3723 (lanes 5 and 6) and hrpV mutant ZJ3724 (lanes 7 and 8), respectively.