Exchange of Genetic Material Between Cells in Plant Tissue Grafts

Hard Graft In plants, it is not clear whether heritable changes can be induced by tissue grafting—for example, when one plant is grafted onto a different root stock. Stegemann and Bock (p. 649 ) now show that genetic material is transferred between plants across graft junctions. This suggests that eukaryotic cells can indeed exchange genetic information, and in this way, grafting allows genes to cross species barriers. Although the exchange is limited to the site around the graft, the finding blurs the boundary between natural gene transfer and genetic engineering techniques and suggests that natural grafting may serve as a mechanism of horizontal gene transfer during evolution.