Induction of a Hypersensitivelike Reaction in Four-o'clock by Clavibacter michiganensis subsp. michiganensis

(...). Injection of four-o'clock with bacterial suspensions was an accurate and rapid way to distinguish C.m. subsp. michiganensis from other bacteria with similar colony morphology recovered from standard or semiselective bacteriological media. Strains of Erwinia herbicola, Pseudomonas fluorescens, and coryne-formlike bacteria that failed to elicit HR in four-o'clock were nonpathogenic to tomato (Lycopersicon esculentum), whereas all strains eliciting HR caused typical symptoms of bacterial canker on tomato and had the characteristics of C.m. subsp. michiganensis