Overcoming plant graft incompatibility by modifying signalling and perception

ended

For millennia, people have cut and joined together different plants through a process known as grafting. Plants tissues from different genotypes fuse, vasculature connects and a chimeric organism forms that combines desirable characteristics from different plants such as high yields or disease resistance. However, plants can only be grafted to closely related species and in some instances, they cannot be grafted to themselves. This phenomenon is referred to as graft incompatibility and the mechanistic basis is completely unknown. Our previous work on graft formation in Arabidopsis thaliana has uncovered genes that rapidly activate in grafted tissues to signal the presence of adjoining tissue and initiate a vascular reconnection process. These genes activate around the cut only during graft formation and present a powerful tool to screen large numbers of chemicals and genes that could promote tissue perception and vascular formation. With these sensors and our previously established grafting tools in the model plant Arabidopsis, we can address fundamental questions about grafting biology that have direct relevance to improving graft formation through: 1. Identifying genes required for the recognition response using forward and reverse genetic screens. 2. Determining and characterising signals that activate vascular induction using a chemical genetics screen. 3. Characterising the transcriptional basis for compatibility and incompatibility by analysing tissues and species that graft and comparing these to tissues and species that do not graft. 4. Overcoming graft incompatibility and improving graft formation by applying the knowledge obtained from the three previous objectives. We thus aim to broaden our fundamental understanding of the processes associated with grafting including wound healing, vascular formation and tissue regeneration, while at the same time, use this information to improve graft formation and expand the range of grafted species.