Figure 14

Proposed model for sporamin gene regulation in sweet potato leaves. Two mechanisms induced by wounding were clarified in this work: activated by abiotic MW or biotic HA. Our findings illustrate that both of them have an impact on different ROS levels and antioxidant mechanisms, which indicates signal components are different. The results presented two wound–induced signals: MW or HA can change the endogenous level of JA or SA to regulate sporamin. MW was shown to be JA-mediated, signaling to regulate the transcription factor IbNAC1 for the activation of sporamin gene expression. On the other hand, HA was shown to be both JA- and SA-mediated, signaling to regulate transcription factors both IbNAC1 and IbWRKY1 for the activation of sporamin against herbivores. This antagonistic difference was further confirmed through the analysis of genes identified in the transcriptome and biological network in the context of MW stress. The selected genes involved in the first line of signaling cascade supports further the partial cross-talk between JA- and SA-mediated signal pathways in regulation of sporamin gene expression.