Figure 3.

MAPK activity in response to consecutive treatments with systemin, OEs, and UV-B. The experimental setup was as in Figure 2. A, L. peruvianum cells were pretreated with the OEs chitosan (CHO), chitotetraose (CH4), β-glucan (GLU), or PGA, with systemin (SYS), or were left untreated. Elicitor concentrations were as indicated in Figure 2. At 30 min thereafter, treated and untreated cells were left untreated or were supplied a second time with a different elicitor. Ten minutes thereafter, cells were quick-frozen and assayed for MAPK activity. The increase in MAPK activity in response to the second treatment after a pretreatment was expressed as percentage of the full response (100%), defined as the response to the second treatment without a pretreatment. B, Cells were pretreated as described in A or were left untreated. At 30 min thereafter, treated and untreated cells were left untreated or were irradiated with UV-B for 5 min. Ten and 90 min after the start of irradiation, cells were frozen and assayed for MAPK activity. The increase in MAPK activity was expressed as in A.