CA-MPK4 partially blocks the constitutive defense responses in anp2-2 anp3-3. A, Morphology of 3-week-old wild-type (WT), anp2-2 anp3-3, and CA-MPK4 anp2-2 anp3-3 plants. B and C, PR1 (B) and PR2 (C) expression levels in wild type, anp2-2 anp3-3, and CA-MPK4 anp2-2 anp3-3. Error bars represent standard deviations from three measurements. D, H. a. Noco2 growth on wild-type, anp2-2 anp3-3, and CA-MPK4 anp2-2 anp3-3. Statistical differences among the samples are labeled with different letters (P < 0.01, one-way ANOVA/Tukey’s test, n = 3).