Figure 6.

Transcriptional Activation in the CDPK Pathway Is Attenuated in adf4 following elf26 Treatment.

Quantitative analysis of marker genes for early defense signaling in the MAPK and CDPK pathways.

(A) to (C) A MAPK-specific reporter gene, FRK1 (A), as well as the MAPK dominant-pathway genes CYP81F2 (B) and WRKY33 (C), were induced in both wild-type and adf4 plants following treatment with elf26 or chitin.

(D) and (E) PHI1, a CDPK-specific response gene (D), and the CDPK-synergistic pathway gene, NHL10 (E), were induced in the wild type following treatment with elf26; however, PHI1 and NHL10 induction was markedly reduced in the adf4 mutant. By contrast, both wild-type and adf4 plants responded with increased PHI1 and NHL10 transcripts following treatment with chitin. Expression of each defense signaling gene and the housekeeping gene GAPD were absent from controls lacking reverse transcriptase (data not shown). Mean values from triplicate biological samples and technical replications are plotted ±se, normalized to GAPD expression and presented as fold induction from mock. Defense gene expression was significantly increased following treatment with either elf26 or chitin on wild-type and the adf4 mutant seedlings compared with mock-treated controls (P < 0.001, ANOVA with Tukey HSD posthoc analysis).