Systemic acquired resistance induced by tobacco mosaic virus in Nicotiana tabacum cv. Xanthi-nc does not disappear at 32°C

Systemic acquired resistance to tobacco mosaic virus (TMV) was induced in Nicotiana tabacum cv. Xanthi-nc plants by incubating them at 22°C for 9 days after inoculating them with TMV. After induction of resistance the plants were incubated for varying periods of time at either 22°C or 32°C before challenge inoculation with TMV on the five leaves above the primary inoculated ones. They were then incubated at 22°C. The level of acquired resistance, as measured by the reduction in lesion size relative to the controls, in plants that had been incubated at 32°C for up to 8 days, was similar to the level in plants that had been incubated continuously at 22°C. Thus, systemic acquired resistance is maintained for at least 8 days in plants incubated at 32°C.