Obtaining Transgenic Potato Plants Expressing the Human Lactoferrin Gene and Analysis of Their Resistance to Phytopathogens

Abstract

The human lactoferrin gene was transferred into genomes of several potato (Solanum tuberosum) cultivars of Ukrainian breeding using the Agrobacterium-mediated transformation. The plasmid vector pBIN35LF carrying the human lactoferrin gene hLf controlled by the 35S cauliflower mosaic virus promoter (CaMV35S) and the octopine synthase terminator, as well as the selective marker neomycin phosphotransferase II gene (nptII) conferring the resistance to kanamycin, was used. As a result of selection, 44 lines of Vernisage, 26 lines of cv. Levada, 25 lines of cv. Svitanok Kyivskyi, and 16 lines of cv. Zarevo cultivars resistant to 100 mg/L of kanamycin were obtained. PCR and Western blot analyses were carried out for transformed lines with primers specific to the hLf gene and a monoclonal antibody against lactoferrin to confirm the transgenic nature of selected tomato plants and hLf gene expression. The selected transgenic potato lines were tested for resistance to bacterial and fungal phytopathogens. The disk diffusion assay revealed that the juice of transgenic potato lines possesses an antibacterial effect against phytopathogenic bacteria Ralstonia solanacearum (causing potato brown rot) and Clavibacter michiganensis subsp. sepedonicus (causing potato ring rot). The resistance of transgenic potato plants to late blight was investigated by in vitro infection of plants with the Phytophthora infestans isolate. As a result, it was found that the obtained transgenic potato lines have enhanced resistance to P. infestans as compared to the control. Thus, the obtained data show that the transfer of the hLf gene into the potato genome enhances potato’s resistance to bacterial and fungal pathogens.