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The in vivo and in vitro interactions between tomato (Lycopersicon esculentum Mill.) and tobacco (Nicotiana tabacum L.) and the bacteria Pseudomonas fluorescens, Acinetobacter baumannii, Rhodococcus erythropolis,Pseudomonas aureofaciens, Pseudomonas putida, Methylovorus mays have been studied. These microorganisms were shown to be in stable associations with plants. The colonized plants were characterized by more rapid growth, a higher yield, and better adaptation to in vivo conditions. The colonized plants were more resistant to bacterial phytopathogens Erwinia carotovora and Pseudomonas syringae. Plants colonized by naphthalene-resistant bacteria can grow steadily on a medium containing this compound. The results demonstrate the prospects of the use of beneficial associative microorganisms in the development of technologies for plant protection against biotic and abiotic stressors.

Marker-free transgenic Camelina sativa (L.) plants carrying a synthetic gene for cecropin P1, an antimicrobial peptide, under the control of the cauliflower mosaic virus 35S RNA promoter have been obtained and analyzed. The plants were transformed with an agrobacterial binary vector free of selective genes of antibiotic and herbicide resistance. The marker-free transformants were screened via measurement of the antibacterial activity of cecropin P1 and enzyme immunoassay. The obtained plants exhibited an increased resistance to infection with the bacteria Erwinia carotovora, the fungi Fusarium graminearum, and oxidative stress during infection. Analysis of the fatty acid composition of seed oil showed an increased amount of α-linolenic acid in the transgenic Camelina lines as compared to unmodified plants. The results indicate that the cecropin P1 gene can be included in an integral antistress plant-protective system.

Kalanchoe pinnata L. plants bearing an artificial CP1 gene encoding the cecropin P1 antimicrobial peptide have been obtained. The presence of the CP1 gene in the plant genome has been confirmed by PCR. Cecropin P1 synthesis in transgenic plants has been shown by MALDI mass spectrometry and Western blotting. The obtained plants have been highly resistant to bacterial and fungal phytopathogens, and their extracts have demonstrated antimicrobial activity towards human and animal pathogens. It has been shown that transgenic plants bearing the CP1 gene can be colonized by the beneficial associative microorganisms Methylovorus mays.

Effects of colonization of micropropagated potato (Solanum tuberosum L.) and strawberry (Fragaria L.) plants by the rhizosphere bacterium Pseudomonas aureofaciens strain BS1393 (VKM B-2188 D) on plant growth and resistance to bacterial and fungal phytopathogens were studied. Pseudomonad colonization improved the physiological characteristics of plants and enhanced their adaptation to in vivo conditions. The presence of P. aureofaciens cells in various plant tissues (leaves, stems, and roots) in vitro was demonstrated on the background of plant cocolonization by two associative strains—P. aureofaciens strain BS1393 (VKM-B-2188 D) and Methylovorus mays (VKM-B-2221). The colonized plants displayed an increased resistance to the phytopathogens Erwinia carotovora, Sclerotinia sclerotiorum, and Phytophthora infestans. These results demonstrate that pseudomonades are promising for practical application in the microbial protection of plants against phytopathogens.