Transgenic plants expressing foreign genes as a model for studying plant stress responses and a source for resistant plant forms

Recent data from the publications concerning transgenic plants have expanded our knowledge of plant defense responses to biotic and abiotic stresses. The results obtained in our laboratory with transgenic tobacco plants expressing bacterial genes, which code for proteins homologous to proteins of plant stress responses, are also described. Expression of the bacterial genes for delta-endotoxin, the proline operon (proB(osm), proA), and a mutant 5-enolpyruvylshikimate-3-phosphate synthase (EPSP synthase) resulted in plant resistance to insect pests, salinity, and glyphosate, respectively. Thus, resistant crops can be produced using bacterial genes. In addition, these results confirm the notion that EPSP synthase is a target of glyphosate action, and proline accumulation is one of the defense responses to salinity. The investigation of transgenic plants expressing the bacterial genes for polyglucanhydrolases, cytokinin biosynthesis (T-cyt), and dioxygenase (nahC) permits us to conclude that these plants are a convenient and adequate model for studying some aspects of stress response.