The in vivo and in vitro interactions between tobacco (Nicotiana tabacum L.), tomato (Lycopersicon esculentum Mill.), cabbage (Brassica oleracea var. capitata L.), rape (B. napus L.), and the common ice plant (Mesembryanthemum crystallinum L.) and bacteria Pseudomonas aureofaciens, P. putida, and Methylovorus mays were studied. Stable associations of these microorganisms with plants are demonstrated. Colonized plants were characterized by accelerated growth, more efficient rooting, better adaptation to in vivo conditions, and enhanced resistance to bacterial and fungal phytopathogens (Erwinia carotovora, Sclerotinia sclerotiorum and Phytophthora infestans). Plants colonized by bacteria resistant to kanamycin and naphthalene can grow steadily on the medium containing these compounds. The results obtained indicate a promising usage of beneficial associative microorganisms for the development of technologies for plant protection against biotic and abiotic stressors. © 2012 Pleiades Publishing, Ltd.