Figure 4.

Identification and expression analyses of key candidate genes involved in the chitin signaling pathway.

(A) A simplified chitin signaling pathway in plants and the key genes under selection. Genes in red are putative candidate genes selected for further analysis.

(B) Chitin treatment and sampling strategy for expression analysis by qPCR. R, pecan scab resistance; S, pecan scab sensitivity.

(C–H) Expression of selected candidate key genes involved in chitin signaling pathways in chitin-treated leaves of the pecan cultivars Excell and Pawnee. Letters show the significance of differences between time points within cultivars (P < 0.05, one-way ANOVA), and stars show the significance of differences between cultivars (∗P < 0.05, ∗∗P < 0.01). qPCR was performed using five replicate leaves from each time point and cultivar.