Model Refinement For Graft Union Development In Plants:Identification Of The Transcriptome And Associated Genes

Grafting is an ancient cloning method that has been used widely for thousands of years in agricultural practices. Graft union development is also an intricate process which involves substantial changes such as organ regeneration and genetic material exchange. However, the molecular mechanisms for graft union development are still largely unknown. Here, we improved the micrografting method that has been used widely in Arabidopsis to facilitate the sample analysis. Based on our new method, we analysed the graft union development. Histological analysis suggested a recovery of transport activities of vasculature at3dag (days after grafting). Investigations of auxin marker DR5with WT plants showed auxin modulated the vascular reconnection at2dag. We performed transcriptional analysis of WT/WT grafts at ldag, and the data revealed a signal exchange process between cells of scion and stock at1dag, which reestablished the communication network in graft union. This communication process concomitant with the cleaning of cell debris, and both of the processes were initiated by a wound-induced program. Based on the microarray data, several genes were analysed to identify their functions in union development. In summary, our results demonstrate the feasibility and potential power of investigating various plant developmental processes by the new micrografting method and represent a primary and significant step in interpretation of the molecular mechanisms underlying graft union development.