Long-Distance Signaling: What Grafting has Revealed?

Grafting has been a long-standing technique used to improve crop production and provide tolerance to biotic stresses, including soil-borne pathogens, as well as tolerance to abiotic stresses, such as cold, salinity, drought, and heavy metals. Currently, beyond its use in horticultural production, grafting has received great prominence as an important research tool, mainly regarding signaling mechanisms related to root–shoot communication. Most of the emphasis from recent studies has been on detection of the long-distance transport of molecules and signaling factors, especially phytohormones, RNAs, peptides, and proteins. Through these studies, there have been significant breakthroughs about the underlying mechanisms implicated in the regulation of developmental and stress responses at the whole plant level. Because of this, the aim of this paper is to provide an overview of grafting as an important tool for plant science. Thus, in the following sections, we will summarize what is most recent and relevant in the use of grafting in plant research.