Agrobacterium is well-known as a vector for transferring genes to plants. In nature, this bacterium infects plants, and induces the growth of galls and roots. These structures result from the precise transfer of a series of genes from Agrobacterium to plant cells. Sometimes, the transformed roots can spontaneously regenerate into new plants and these plants still carry the transferred Agrobacterium genes. Such root regenerants can therefore be considered as naturally genetically modified organisms (nGMOs). They are interesting examples of horizontal gene transfer, the transfer of genes between different species. It has been shown that certain nGMOs continue to express these Agrobacterium genes and as a consequence, produce new substances. Up to now, only three types of nGMOs had been identified: tobacco, Linaria and sweet potato, and it was believed that such plants were extremely rare. Recently, highly efficient DNA sequencing techniques have been developed, and an evergrowing number of plant sequences is now available in public data banks. A detailed analysis of these sequences has revealed 41 nGMOs. These species comprise well-known plants like tea (Camillia sinensis), hops (Humulus lupulus), peanut (Arachis hypogaea), cranberry (Vaccinium macrocarpon), guava (Psidium guajava), banana (Musa acuminata) and other plants used for food and drinks. Various transgenes appear intact, but their functions are still unknown, and will need further study. Extrapolating the data leads to an estimation of at least 10.000 Angiosperm nGMOs. This work was carried out by Léon Otten (emeritus Professor at the University of Strasbourg, France) and Tatiana Matveeva of the University of Saint-Petersburg, Russia. The results have been published in Plant Molecular Biology in September 2019.
Reference : Matveeva, T. M. and Otten, L. (2019) Widespread occurrence of natural genetic transformation of plants by Agrobacterium. Plant Molecular Biology, September 2019. doi: 10.1007/s11103-019-00913-y
Figure legend. Some naturally transformed plants: banana, peanuts, tea and hops (an ingredient of beer).