Figure 4.

Crosstalk between MAPK and CPK3 kinase activities, and induction of marker genes, upon salt stress.(a) Salt-triggered induction of known salt stress-responsive marker genes was compared among the wild type (Col-0), cpk3-2, and the two CPK3 overexpressor lines by RT-PCR, and compared with Actin (ACT3) as an internal control. Gene identifiers and sequences of the used primers are listed in Table S1. Fourteen-day-old seedlings were treated with 150 mm NaCl for the indicated time periods, as described in the Experimental procedures.(b) Salt-triggered activation of MPK6 in wild type (Col-0), cpk3-2 knock-out, and two independent CPK3 overexpressor lines towards myeline basic protein (MBP) as generic substrate. Kinase activities were measured in immunocomplex kinase assays upon salt treatment of 14-day-old seedlings for 15 min, as described in the Experimental procedures.