Natural GMOs: a history of research

Agrobacterium mediated transformation underlies the production of most modern lines of transgenic plants. At the same time, in nature, plants are described that have been transformed by Agrobacterium without human intervention. They are called natural GMOs. 
Such plants were first described by White in 1983 [1] within the genus Nicotiana L., and the phenomenon of horizontal gene transfer from Agrobacterium to plants was considered unique for representatives of this genus for a long time. Only in 2012, another genus of natural GMOs was found. It was Linaria Mill. In 2019, the list of species of natural GMOs was increased by an order of magnitude and is constantly updated until now [2]. 
Several stages can be identified in the history of natural GMO research: 1. Description of individual examples of natural GMOs. 2. Estimation of the frequency of the horizontal gene transfer from Agrobacterium to plants based on the analysis of NGS data. 3. Description of the diversity of cT-DNA in terms of composition and copy number [3]. 4. Studies of the functions of individual pGMO genes [4]. 5. Phylogenetic studies of natural GMOs [5]. 
During the analysis of cT-DNA of natural GMOs, it became clear that they differ in the composition and intactness of transgenes, which can be interpreted from the point of view of the lack of a common function in all cT-DNAs. Genes that were not previously found in known Agrobacterium strains, are identifiedIn in cT-DNAs, indicating a greater biodiversity of Agrobacterium than previously thought [2]. Many cT-DNA genes are intact and expressed. For some it was possible to identify products [4]. All these discoveries lead us to understanding of the role of horizontal gene transfer from Agrobacterium to plants during their evolution. 
The work was performed using the equipment of the RC of St. Petersburg State University Development of Molecular and Cellular Technologies and Biobank with the support of the Ministry of Science and Higher Education of the RF in accordance with agreement No. 075-15-2022-322 dated 04/22/2022 on the provision of a grant in the form of a subsidy from the Federal budget of the Russian Federation for the creation and development of the world-class Scientific Center Agrotechnologies for the Future.