Figure 3.

UV-B activates MPK3 and MPK6 in leaves of wild-type (WT) Col-0 and Ws and hyperactivates MPK3 and MPK6 in leaves of the mkp1 mutant. A, Leaves of wild-type Col-0 were exposed to different doses of UV-B for 2 h. B, Leaves of wild-type Col-0 were exposed to 0.5 W m⁻² UV-B for the indicated times or leaves of mutants mpk3-1 and mpk6-4 were exposed to 0.5 W m⁻² UV-B for 2 h. C, Leaves of wild-type Ws, mutant mkp1, and line 6 (a representative line of mkp1 complemented by the expression of wild-type MKP1) were exposed to 0.5 W m⁻² UV-B for the indicated times. After treatment, total proteins were extracted from the treated leaves and immunoblot analysis was performed with anti-phospho-p44/42 MPK and anti-actin (loading control) antibodies.