To investigate the involvement of SA-signalling via NPR1 pepper seedlings were infiltrated with a mixture of A. tumefaciens strains of pTRV1 (CaMV 35S-driven TRV RNA1) and pTRV2-NPR1 (TRV RNA2 containing the target sequence), or pTRV2-GFPsil (serving as a control for infection symptoms). This evidence concerns the gene NPR1 and infection.