PtWOX11 Promote de novo Shoot Regeneration by Involving a Two- Step Mechanism in Poplar

De novo shoot regeneration is an essential step for massive propagation and genetic engineering of elite germplasm in forestry. Poplar that is a fast growth tree species have a very important ecologically and economically role around the world, especially in China. In this study, we found that PtWOX11 that is a homologue of AtWOX11 not only involved de novo root formation but also promote de novo shoot regeneration in poplar. We demonstrated that PtWOX11 can enhance callus regeneration competence and shoot regeneration during two-step de novo shoot regeneration. Furthermore, by using RNA-seq and qPCR, we uncovered that during callus induction stage PtWOX11 activates PtPLTs expression to promote callus formation and regeneration competence, and promote PtCUC2/3, PtWUSa and PtSTM transcription to fulfil shoot organogenesis during shoot regeneration stage. Overall, our data indicated that PtWOX11 play a new function and transcriptional regulation mechanism on de novo shoot regeneration in poplar. RNA-seq of leaf, callus on CIM8, SIM4 and SIM8