Figure 5.

PR-1 gene expression in wild-type (WT) and transgenic NahG tobacco plants exposed to gaseous MeSA. Five-week-old tobacco plants were enclosed in gas-tight glass chambers containing 250 μg L⁻¹ MeSA. After the 6-d incubation period, fully expanded leaves were removed from plants and analyzed for PR-1 gene transcription. Total RNA was isolated and the PR-1 transcript was detected by hybridization with a cDNA probe (top). A probe for rRNA (18S) was used to demonstrate equal RNA loading (bottom).