FIGURE 2.

Transgenic tobacco plants overexpressing MsProDH show an increased Pro oxidation activity. A, RNA blot showing the constitutive high MsProDH expression in leaves of transgenic plants grown under normal conditions (Control, C) or irrigated with 150 mm NaCl for 48 h (S). MsProDH cDNA was used as a probe. B, ProDH-dependent tolerance to the Pro toxic analogue T4C. One-week-old tobacco seedlings were transferred to MS, MS+ 50 mm NaCl, MS + 3 mm T4C, or MS+50 mm NaCl + 3 mm T4C medium and photographed 3 weeks later. Upper panel, WT plants highly sensitive to T4C + NaCl combination (right photo). Lower panel, ProDH-OE plants grown on MS + NaCl + T4C with no toxic effects. C, Pro oxidation assay in WT and ProDH-10 plants. Leaf proteins were extracted from 10-day water-stressed plants. The activity was measured in the presence of increasing Pro concentrations, using NAD⁺ as the electron acceptor. Standard deviation represents three replicates. ProDH-1, -4, -6, and -10 are independent transgenic lines harboring the MsProDH expression cassette.