The bacterial spot caused by pathogen Pseudomonas syringae pv. tomato (P.s. tomato) is a devastating disease affecting tomato plants. The invention shows that the mere inhibition of the expression of gene Ep5C, coding an extracellular cationic peroxidase is sufficient to impart marked resistance to P.s. tomato. Said inhibition found in tomato plants provides a resistance with no need for activation of defense pathways currently described and controlled by salicylic acid and jasmonic acid. In addition the invention shows that Ep5C is repressed at the transcription level in healthy plants through the formation of a stable complex including proteins and one cis acting element identified within the 5' region of the gene promoter. Said complex is disabled in tissue infected with P.s. tomato and shows maximum expression in the gene. Thus Ep5C gene as well as its promoter provides a new genetic asset to develop plants resisting to the bacterial spot disease.