Figure 3.

Induction of myb1 by TMV infections during the hypersensitive response. (A) RNA blot analysis of myb1 and PR-1 gene expression following TMV infection at 22°C in the resistant tobacco cultivar Xanthi nc. Time is indicated in h postinfection. (B) Accumulation of myb1 and PR-1 mRNA following shift of Xanthi nc plants from a temperature where resistance to TMV cannot develop (32°C) to a temperature at which resistance is established (22°C). RNAs were isolated from inoculated leaves. Time is indicated in h posttemperature shift. TMV- and mock-inoculated plants were maintained at 32°C for 48 h after inoculation before being transferred to 22°C.