Figure 4.

Evaluation of the ability of transgenic tomato suspension cultures (±Pto) to respond to generic elicitors of the oxidative burst. Transgenic tomato cells expressing the Pto transgene (BC-R) (A) or lacking Pto (BC-S) (B) were cultured for 18 hr and either left untreated (control), treated with 50 μl OGA (0.5 mg/ml) or diluted with an equal volume of distilled water (1:1 dilution) to induce a mechanically stimulated oxidative burst. The quenching of pyranine fluorescence due to H₂O₂ production was then followed spectrofluorimetrically as a function of time. Similar results were obtained in three independent experiments.