Fig. 8.

MKKK18 activity increases in the abi1td mutant in response to ABA treatment. (A) Seedlings of WT Col-0 and the abi1td and snrk2.6 mutants were treated with 100 µM ABA for the indicated times. A 600 µg aliquot of total protein was used for the immune complex MKKK18 activity assay using anti-MKKK18 antibody. Coomassie Brilliant Blue (CBB) staining of MBP confirmed equal loading. Due to low abundance, the endogenous MKKK18 protein was not detectable by immunoblot analysis. The results shown are representative of three independent experiments (n = 9) with consistent results. (B) ³²P-labeled MBP bands were quantified using ImageJ software and normalized by taking the radioactivity of the band in the absence of ABA as 1. Data are means ± SD of the relative band intensities from three independent experiments (n = 9).