Figure 3

Confirmation of OsMT1e-P transgenic tobacco plants and assessment of their tolerance towards salinity stress. (A) Schematic representation of construct (pCAMBIA OsMT1e-P ) used to ectopically express OsMT1e-P in tobacco plants. (B) PCR analysis of the wild type (WT) and T₀ transgenic lines (L1, L2 and L7) to confirm the integration of the OsMT1e-P gene. (C) Northern blot analysis of OsMT1e-P transcript in shoots of seven days old WT and T₀ transgenic lines (L1, L2 and L7) under unstressed condition. (D) Ethidium bromide stained RNA gel used as loading control for northern blot analysis of samples used in C. (E) Northern blot analysis of OsMT1e-P transcript in shoots of seven days old WT and T₀ transgenic lines (L1, L2 and L7) under salinity (200 mM NaCl, 48 h) stress condition. (F) Ethidium bromide stained RNA gel used as loading control for northern blot analysis of samples used in E. (G) Histogram depicting signal intensity of OsMT1e-P transcript in WT and T₀ transgenic lines (L1, L2 and L7) under unstressed and salinity (200 mM NaCl) stress conditions as obtained from C and E above. (H) Germination assay of OsMT1e-P transgenic seeds (T₁) on MS media supplemented with various stressors. For this purpose, medium was supplemented with either NaCl (100 or 200 or 300 mM) or CuSO₄ (5 mM) or PEG (5%) or ZnSO₄ (5 mM or 10 mM). Seeds sown on plain MS medium served as control. (I) Histograms depicting fresh weight of WT and OsMT1e-P transgenic seedlings grown under various stress conditions. The seedlings were maintained under culture room conditions (28 ± 1⁰ C, 16 h light/8 h dark) and their growth was monitored for 15 days under different stresses and fresh weight of surviving seedlings was measured. The data represent means ± SE of three biological replicates (n = 3). Bars with different letters are statistically significant and those with the same letters are not significantly different (p < 0.05).