Figure 3

Response of WT and cycam1 to different A. brassicae -derived stimuli. The roots of 18-day old WT and cycam1 seedlings were dissected and incubated overnight in 7.5 μM coelenterazine. The roots of WT, cycam1-1 and cycam1-2 were challenged with 50 μl of CWE (A), EPM (B), EPS (C) or Tox (D). The mutants did not respond to the CWE, EPM and EPS (A-C) but responded to the Tox preparation (D). pMAQ2 in Col-0 seedlings served as control. Refractory behavior of the fungal stimuli to [Ca²⁺]_cyt changes in WT and cycam1-2 were determined by competition assays (E-H). WT and mutant roots were first treated either with the CWE, the EPM or EPS and subsequently 10 min later with CWE (E) or the Tox (E-H). The CWE-induced [Ca²⁺]_cyt change is refractory to consecutive applications of CWE but non-refractory to the second treatment with Tox in WT roots (E). The CWE, EPM or EPS induce [Ca²⁺]_cyt changes in WT, but not cycam1-2 roots, while both WT and mutant responded to subsequent treatment with the Tox (E-H). All curves represent average of four independent experiments with eight replications in each experiment.