The plant phloem system transports both essential nutrients and long-distance signaling agents. Recent transcriptomics studies and grafting experiments have demonstrated that several thousand mRNAs and various small noncoding RNAs are moved over long-distances via the phloem. Therefore, by using grafting, it is possible to deliver artificial RNAs which are derived from a designed DNA construct in the transgenic plant into the graft partner plant, and to induce heritable TGS （transcriptional gene silencing） via RdDM （RNA directed DNA Methylation）. We developed an epigenome editing system of an endogenous gene of potato （Solanum tuberosum）. We address potential function of siRNA（small interfering RNA） in grafting system with respect to epigenetic breeding.
