As a result of the genetic transformation of plants, the loss of a transformant's ability to express the transgene becomes frequent. The causes of such silencing transgenes can be various factors. For example, micropropagation of transgenic plants or their long-term cultivation can lead to a gradual decrease in the expression level of a transgene. At the present study, the preservation of transgenes after five years of cultivation of genetically modified plants of Berlin poplar under laboratory conditions in the absence of a selective factor in a nutrient medium was carried out. Berlin poplar (Populus ×berolinensis Dippel) is a hybrid of laurel poplar (Populus laurifolia Ledeb.) and Italica black poplar (P. nigra L. “Italica”). Genetic transformation of plants was performed using the C58C1 strain of Agrobacterium tumefaciens. The transformation vector pBI121 (Clontech, USA) containing the selective neomycin phosphotransferase II gene – nptII, which determines resistance to kanamycin sulfate and the E. coli reporter uidA gene encoding bacterial enzyme β-D-glucuronidase was used. The transfer of the vector into A. tumefaciens cells was carried out using direct transformation by the freeze-thaw method. The studied transgenic plants of the Berlin poplar were characterized by stable (constant) expression of the uidA and nptII genes. Despite the absence of a selective agent in the nutrient medium, the activity of the nptII gene did not decrease or disappear after 5 years of keeping the plants in a sterile laboratory culture. It is shown that the applied approach of agrobacterium mediated genetic transformation of Berlin poplar can be effectively used to obtain stable transgenic plants without losing newly acquired properties after at least 5 years.

Pavlichenko Vasiliy Valeryevich, Candidate of Science (Biology), Senior Research Scientist, Siberian Institute of Plant Physiology and Biochemistry SB RAS, 132, Lermontov st., Irkutsk, 664033, Russian Federation, tel.: (3952) 42–46–59, fax (3952) 51–07–54, e-mail: vpavlichenko@gmail.com 

Protopopova Marina Vladimirovna, Candidate of Science (Biology), Senior Research Scientist, Siberian Institute of Plant Physiology and Biochemistry SB RAS, 132, Lermontov st., Irkutsk, 664033, Russian Federation, tel.: (3952) 42–46–59, fax (3952) 51–07–54, e-mail: marina.v.protopopova@gmail.com 

Voinikov Victor Kirillovich, Doctor of Sciences (Biology), Principal Research Scientist, Siberian Institute of Plant Physiology and Biochemistry SB RAS, 132, Lermontov st., Irkutsk, 664033, Russian Federation, tel.: (3952) 42–46–59, fax (3952) 51–07–54, e-mail: vvk@sifibr.irk.ru

Pavlichenko V.V., Protopopova M.V., Voinikov V.K. Results of a Five-year Laboratory Cultivation of the Berlin Poplar Genetically Modified with uidA and nptII Genes. The Bulletin of Irkutsk State University. Series Biology. Ecology, 2018, vol. 25, pp. 3-14. https://doi.org/10.26516/2073-3372.2018.25.3 (in Russian)

agrobacterium mediated transformation, nptII, uidA, GUS-reporter system, Populus ×berolinensis, transgenic plants, stable transformation

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