Symptoms observed on N. benthamiana plants after inoculation with A. tumefaciens containing the binary PVX vector expressing P. infestans crn1 and crn2 cDNAs. Inoculated leaves and plantlets of N. benthamiana were photographed 12 (A,C,E) or 16 (B,D,F) d after inoculation with A. tumefaciens containing the binary PVX vector pGR106 (Jones et al. 1999) (A,B), pGR106 derivative expressing crn1 cDNA (C,D), or pGR106 derivative expressing crn2 cDNA (E,F). Panels B, D, and E correspond to an independent experiment from panels A, C, and F, in which smaller plants were inoculated, resulting in faster systemic spread of the virus. Panels A,B show no symptoms at the inoculation site and systemic mosaic symptoms typical of PVX infection. Panels C–E show localized necrosis at site of inoculations, and panels D–F show systemic necrotic symptoms. Note that the symptoms obtained with the crn2 construct were observed as early as 5 d after inoculation, and the symptoms induced by crn1 occurred later, starting around 12 d after inoculation.