Figure 3

Increased salt tolerance in transgenic rice plants over-expressing SAPK4 . (A) Northern-type hybridization of the expression of SAPK4 in leaves of wild-type rice (WT) and the SAPK4 over-expressing rice lines S1 and S4 grown under control conditions and analysis of the SAPK4 transcript levels by RT-PCR in leaves of wild-type rice (WT) and the SAPK4 over-expressing rice lines S1, S4, and S5 exposed to 150 mM NaCl for 48 hours. Analysis of the SAPK4 transcript levels by RT-PCR in leaves of wild-type rice (WT) and the rice lines C1 and C2 that were transformed with the empty plant expression vector and that were exposed to 150 mM NaCl for 48 hours is shown as a control. Transcript levels of actin are shown as a loading control. (B) Phenotype of wild-type rice and transgenic rice plants over-expressing SAPK4. The plants were grown to the age of 8 weeks in hydroponic culture. Control plants and plants that were treated with 150 mM NaCl for up to 7 days. (C) Growth performance of wild-type rice and the SAPK4-over-expressing lines. Values are means ± S.D. (n = 30).