Devadas and Raina (2002) demonstrated that the P. syringae pv. maculicola ES4326 strain harboring avrRpm1 failed to elicit HR in the Arabidopsis Col-0 plants pre-treated with SA. Rate and Greenberg (2001) reported that the NPR1-overexpressing Arabidopsis plants exhibited a reduced HR response, while the npr1 mutants displayed a more severe HR, in the infection assays conducted with P. syringae carrying the avrRpm1 gene. These studies suggest that SA is a multifaceted phytohormone involved in various signal transduction systems in plant immune responses (Li et al., 2019a). The gene discussed is NPR1; the disease is infection.