The regulatory implications of using transgrafted plants are currently unknown. A plant's vascular system can selectively transport across graft junctions endogenous elements such as full-length RNAs, sRNAs, proteins, hormones, metabolites and vitamins, and even elicit epigenetic effects, heritably changing the way genes are expressed without changing the actual DNA sequence. However, not all of these elements are transported freely, and they either require specific molecular signals or cellular transporters to aid in their movement through a plant's vascular system.
