XgΔavrHah1 has an in-frame deletion of the DBD. (A) Schematic of the in-frame deletion that removes the DBD from avrHah1 to create avrHah1ΔDBD. NLS, nuclear localization signal. (B) Southern blot analysis of BamHI-digested genomic DNA from X. gardneri strains listed probed for the DBD (Top) or the T3SS (Bottom). The size of BamHI-digested avrHah1 is 2,964 bp, and the size of BamHI-digested DBD deletion of avrHah1 is 1,491 bp. (C) Cell death (or HR) occurs in response to activation of the Bs3 resistance gene in pepper 30R and appears here as a dark, opaque area. XgΔavrHah1 does not activate Bs3 and is pathogenic on pepper 30R. Complementation of XgΔavrHah1 with avrHah1 or avrBs3 restores activation of Bs3 resistance and HR in pepper 30R.