Inducible xopB expression in transgenic tobacco plants causes severe leaf abnormality.
A.) Analysis of xopB-specific transcript accumulation in transgenic tobacco lines. Seven different lines (No. 22, 26, 37, 44, 64, 71, 72) and two control plants (wt) were analysed for xopB expression by Northern blotting. Total RNA was isolated 1 day after watering plants with 1% ethanol to induce xopB expression. Twenty µg of RNA were separated on a formaldehyde-containing agarose gel and analysed by hybridization with a xopB-specific radioactively labelled probe. Ethidium bromide stained rRNA is shown as loading control. B.) Analysis of XopB protein accumulation upon watering with 1% ethanol in selected transgenic lines (#22, #71). XopB migrates at ∼70 kDa, while in tobacco a cross-reactive band appeared at ∼55kDa. Expression of RubisCO as stained by Coomassie Blue is shown as control for protein loading. C.) Phenotypic changes in transgenic tobacco plants caused by xopB expression. Upper panel: symptoms 2 days after ethanol-treatment; lower panel: phenotypic alterations 10 days after induction. Arrows indicate morphological changes of the leaf lamina and cell death of meristematic tissue, respectively. From left to right: control line, lines #22 and #71.