NtWRKY-R1-mediated Tobacco Topping Injury Signaling Pathway

Nicotine, as a kind of secondary metabolism, was produced by tobacco in root. Topping was an obbligato technology method in tobacco production. It can provide nutrition for leaves’ development and gain tobacco production, and activate the defense system of tobacco at the same time. As a result, the content of nicotine accumulated rapidly. In order to elucidate the molecular mechanism of increased nicotine content, I chosen an EST from SSH c DNA library constructed by our research group before for understanding the influence of topping on nicotine synthesis.We can get five points about our work:Nt WRKY-R1 was divided into GroupⅡe of plant WRKY family through bio-information analysis.Nt WRKY-R1 and GFP co-expressed in nuclei of tobacco cells.To deepen the understanding of Nt WRKY-R1, we have constructed over expression of Nt WRKY-R1 lines in tobacco and Aradopsis. In Aradopsis, we demonstrated that Nt WRKY-R1 activated SA signaling and repressed JA signaling by relevant makers about different signaling pathways.Over expression of Nt WRKY-R1 in tobacco(OvNt WRKY-R1) flowered earlier than wild type and was incapable of fructifying successfully.We also used the roots and leaves of OvNt WRKY-R1 to detect the relative expressions of genes involved in flowering, SA, IAA and JA signaling, and synthesis of nicotine. Among pathways mentioned above, SOC1, IAA13 were up-regulated, but PMT1 a was down-regulated. It was assuring that this transcription factors was participated in all these signaling, simultaneously.Together, it can positive regulated synthesis of tobacco nicotine and be involved in many signaling pathways synchronously.