Induction of the hypersensitive response on tobacco (Nicotiana tabacum) by different Acidovorax citrulli strains. Leaves were infiltrated with 1, AAC00-1hrcC
(nonpathogenic hrcC mutant of AAC00-1); 2, AAC00-1hrcCcomp (complemented hrcC mutant of AAC00-1); 3, AAC00-1 (wild-type A. citrulli); and 4, 0.1 M phosphatebuffered
saline (PBS, negative control) at 1 × 106 CFU/ml.