A role of Jasmonate in adventitious rooting in Arabidopsis

Jasmonate (JA) controls plethora of developmental processes including adventitious root initiation (ARI). We have previously shown that auxin signaling promotes ARI by antagonizing with MYC2-dependent JA signaling. To get mechanistic insights into the role of MYC2-mediated JA signaling in this process, we performed RNA-seq between ninja myc2-322B double mutant (which produce very few AR) and the wild-type seedlings at different three stages of ARI (darkness at T0, just before exposure of some of the etiolated seedlings to light. Further samples were collected after 9 and 24 h in long-day conditions (T9 and T24, respectively). We identified several differentially expressed genes. Among the candidate genes we retrieved ERF115 transcription factor, which belongs to AP2/ETHYLENE RESPONSE FACTOR family. Interestingly, the overexpressing ERF115 line (35S:ERF115) phenocopied ninja myc2-322B in term of AR number, suggesting a genetic link between MYC2 and ERF115 genes. We demonstrated that ERF115 represses ARI by activating the cytokinin signaling machinery. Altogether, our data suggest that JA-induced ERF115 acts as a "molecular switch" for auxin and CK interplay during ARI.