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 expande d our knowledge of plant defense responses to biotic and abiotic stresses. The results obtained in our laboratory with transgenic tobacco plants expre ssing bacterial genes, which code for proteins homologous to proteins of pl ant 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 r esults confirm the notion that EPSP synthase is a target of glyphosate acti on, and proline accumulation is one of the defense responses to salinity. T he investigation of transgenic plants expressing the bacterial genes for po lyglucanhydrolases, cytokinin biosynthesis (T-cyt), and dioxygenase (nahC) permits us to conclude that these plants are a convenient and adequate mode l for studying some aspects of stress response.