Figure 1.

Infiltration of SA, fungal cell wall elicitor, and water activate a 48-kDa kinase in tobacco leaves. (A) Tobacco leaves were infiltrated with either SA (1 mM) or water, and samples were taken at the indicated times. Kinase activity was determined with an in-gel kinase activity assay by using MBP as the substrate. The size of the activated kinase is given in kilodaltons (kDa). (B) The 48-kDa kinase activities detected in SA-infiltrated (•) and water-infiltrated (○) leaves were quantitated by using a PhosphorImager (Molecular Dynamics), and the relative activities were plotted against time. Kinase activities were normalized to the level present at the zero time point, which was given a value of 1. (C) Tobacco leaves were infiltrated with either a cell wall elicitor (Eli) from P. parasitica (100 μg of glucose equivalent per milliliter) or water, and samples were taken at the indicated times and analyzed as in A. (D) The 48-kDa kinase activities in fungal cell wall elicitor-infiltrated (•) and water-infiltrated (○) leaves were quantitated by using a PhosphorImager, and the relative activities were plotted against time as in B. The difference between elicitor- and water-infiltrated leaves, which presumably represents the elicitor effect, is depicted as a line with triangular symbol (▴).