Figure 5

Correlations between transgene expression level and O₃ tolerance observed in various Arabidopsis lines overexpressing different phytocyanin genes. (a–c) The levels of mRNA encoding AtUC5 (a), AtUC6 (b), and AtSC3 (c) extracted from 2-week-old seedlings of each transgenic line were measured using reverse transcription PCR and relative values against the control plants (wt) are shown in the upper figure. Images of various plant lines 1 day after 2 h exposure to fresh air or 0.3 μL L⁻¹ O₃ under 420 μmol photons m⁻² s⁻¹ illumination are shown in the middle figure. The amounts of ion leakage from the leaves of plants that received either 0 or 2 h fresh air or 0.3 μL L⁻¹ O₃ under an irradiation at 420 μmol photons m⁻² s⁻¹ are shown in the bottom figure. Line names shown in the bottom figure also represent those of the upper and middle figures just above the bottom results. For the upper and bottom results, the mean and SD are shown (n = 3–16) and means with the same letter are not significantly different from each other at p < 0.05. FA fresh air, wt wild type, vector a plant to which only vector was introduced, OE:AtUC5-1(or 2, 3, 4, 5) AtUC5-overexpressing lines, OE:AtUC6-1(or 2, 3, 4) AtUC6-overexpressing lines; AtSC3-1 (or 2, 3, 4, 5), AtSC3-overexpressing lines. (d) Correlations between levels of transgene expression and ion leakage from leaves treated with ozone for 2 h, in various transgenic lines. The correlation coefficient (r) of the linear relationship for each transgenic line is shown in the figure.