Heterografting with nonself rootstocks induces genes involved in stress responses at the graft interface when compared with autografted controls

Although grafting is widely used in the agriculture of fruit-bearing crops, little is known about graft union formation in particular when two different species are grafted together. It is fascinating that two different plant species brought together can develop harmoniously as one organism for many decades. The objective of this study was to determine whether grafting two different grapevine genotypes alters gene expression at the graft interface in comparison to the presumably wound-like gene expression changes induced in autografts. Gene expression at the graft interface was studied 3, 7, 14, and 28 d after grafting in hetero- and autografts of grapevine (Vitis spp.). Genes differentially expressed between the hetero- and autografts during graft union formation were identified. These genes were clustered according to their expression profile over the time course. MapMan and Gene Ontology enrichment analysis revealed the coordinated upregulation of genes from numerous functional categories related to stress responses in the hetero- compared to the autografts. This indicates that heterografting with nonself rootstocks upregulates stress responses at the graft interface, potentially suggesting that the cells of the graft interface can detect the presence of a nonself grafting partner.