PD-GRAFT · Uncovering the Role of Plasmodesmata in Plant Graft Healing

Despite its long history and importance for combining desirable traits such as yield, stress resistance and fruit quality, plant grafting is still restricted to a few closely related species. To overcome the cellular and molecular barriers underlying graft failure, termed incompatibility, we need an in-depth understanding of how cells at the graft interface communicate to coordinate their fusion and regeneration into a successful graft. Together with recent reports of vast formation of plasmodesmata (PD), nanoscale channels that mediate exchange of molecules and signaling cues between plant cells, my preliminary data of dynamic callose accumulation at the graft interface in Arabidopsis hypocotyls leads me to suggest that PD-mediated cell-to-cell communication is key for graft success. However, to date, the nanoscale of PD structures and necessity of capturing transcriptional changes at single cell resolution cause methodological challenges that preclude PD’s precise roles in grafting. Meeting these challenges, I will in PD-GRAFT acquire the skill-set needed for integrating super-resolution microscopy and single-cell RNA sequencing to decipher the role of PD-mediated communication during grafting, and use this knowledge to improve grafting success. To do so, I will join Prof. Melnyk’s lab (host) and engage in two secondments to complement my current expertise in PD regulation, including grafting, regeneration, single-cell transcriptomics and PD ultrastructural imaging. While boosting my career as an independent researcher, this will allow me to provide novel insights into the molecular regulation of grafting and regeneration, specifically revealing the spatiotemporal dynamics, molecular regulators and functional roles of PD during grafting. By pinpointing key candidates, PD-GRAFT will further guide novel solutions for improving graft compatibility in agriculture and horticulture, in support of the European Grean Deal and EU’s priorities for sustainable development.