Figure 4.

Induction and priming by direct BTH treatment and exposition to VOCs from BTH-treated plants. A, RT-PCR shows an induction of PR-2 by direct BTH treatment (0 h) and a priming effect on this gene, which was strongly expressed 6 and 12 h after P. syringae inoculation (hpi) when plants had already been treated with 0.5 mm BTH. Lima bean exposed to the directly BTH-treated plants (Indirect) also showed a priming effect (PR-2 expression 6 h after infection stronger than in controls). The housekeeping gene Actin was used to indicate equal loading. B and C, Expression levels as quantified by qRT-PCR (B) confirmed these results, while no significant responses of LOX expression could be observed (C). Bars represent means ± se. Sample size was n = 3 replications per treatment. The experiment was repeated three times with similar results.