Figure 9.

SoSnRK2 activation in response to NaCl (A), ABA (B), H₂O₂ (C) and cold (D) stress. Arabidopsis protoplasts were transiently transformed with the empty vector (*) or the expression vector for each SoSnRK2. Protoplasts were transferred to isosmotic medium [400 mOsm (−)] or NaCl salt stress [1000 mOsm (+)] for 15 min (A); For ABA (B) and oxidative stress (C), protoplasts were incubated with 100 µM ABA (+) or 10 mM H₂O₂ ( + ), or the same volume of ethanol solvent control (−) for 20 min (C), respectively. Protoplasts were incubated at room temperature (−) or at 4 °C (+) for 20 min for cold treatment (D). Number 1–10 on the head of the figure indicated the SoSnRK2.1-SoSnRK2.10. HA-tagged SoSnRK2 proteins were immunoprecipitated from protoplasts protein extracts with anti-HA antibody and analyzed by in-gel kinase assay using MBP as a substrate (upper panel). The expression of each kinase was monitored by immunoblotting the same extracts with anti-HA antibody (lower panel).