Transformation Mediated by Agrobacterium tumefaciens

摘要: The soil bacterium Agrobacterium tumefaciens can be used nowadays as a vector for the genetic transformation of organisms diverse plants, yeasts, and filamentous fungi. For century this has been recognized etiological agent plant disease crown gall, characterized by tumorous overgrowths that occur mostly on root plant. In laboratory gall induced at any part wounding infecting with bacterium. Fifty years ago it was discovered cells differ from normal their ability to grow in absence growth regulators (Braun, 1958). They do so even inducing Agrobacteria, concluded, therefore, are tumor cells. How transforms into elucidated several later. introduces segment oncogenic DNA, called T(transferred)-DNA infection sites (Chilton et al., 1977), converts because DNA directs synthesis regulators. By receipt T-DNA, concomitantly acquire produce tumor-specific metabolites opines (Figure 4.1). Different strains may provoke tumors different types opines. Thus classified octopine strains, nopaline leucinopine etc. produced (and secreted by) dividend gained having provoked tumor, only agrobacteria catabolize formed (Petit 1970). example, which induce producing octopine, utilize (but not, instance, nopaline) growth, whereas conversely making degrade not octopine). process induces tumors, is often referred colonization, modification host creates favorable niche horizontal transfer T-DNA plants have played role evolution, seen genus Nicotiana, where segments naturally present genomes species (Aoki Syono, 1999).