K361M seedlings are responsive to treatment with flg22 peptide. A, Five-day-old seedlings subsequently treated with and without 10 μm flg22 peptide for 10 d. Error bars indicate se. B, Ten-day-old seedlings treated with 10 μm flg22 peptide for 24 h and stained for callose deposition. Independent replicated experiments gave similar results for both A and B. mekk1 + MEKK1, mekk1-1 mutant stably transformed with the wild-type MEKK1 gene. mekk1 + K361M, mekk1-1 mutant stably transformed with MEKK1 (K361M). fls2, fls2-101/fls2-101 T-DNA mutant.