Identification of Phloem Mobile mRNAs Using the Solanaceae Heterograft System.

Large numbers of mRNAs move in the phloem and some may function as signals to exert important physiological functions in the distal recipient organs. Generating an authentic list of phloem mobile mRNA is a prerequisite for elucidating their physiological functions. Nicotiana benthamiana can be used as a scion to graft on a tomato (Solanum lycopersicum) rootstock. Thereby, shoot-to-root mobile N. benthamiana mRNAs transported via the phloem can be identified from the root of the tomato rootstock. Due to the close relationship and similar genome sequences of the two species, stringent informatics procedures should be applied to avoid false identification. This heterograft system can be used to study physiological processes associated with mRNAs that are mobile under either normal or adverse growth condition.