a, Flg22 stimulates endogenous CDPK activities. Calcium-dependent histone phosphorylation, abolished by EGTA, is stimulated by flg22 at 15 min. b, NHL10 is an early flg22 responsive gene. c, Flg22 activation of NHL10-LUC is dependent on the FLS2 receptor. The fls2 mutant is complemented by FLS2-HA. Error bars, s.d. (n=8). d, Flg22 signalling requires calcium and PK activity. Inhibitors: 1 mM LaCl3 (La), 0.5 mM GdCl3 (Gd), 2 μM K252a (K). Error bars, s.d. (n=6). e, Specific CPKac can activate NHL10-LUC. Error bars, s.d. (n=6). Mesophyll protoplasts (a–d) were treated with 100 nM flg22. The expression level of FLS2-HA and CPKac-FLAG was monitored by immunoblot.