Characterization and host range of five tumorigenic <i> <scp>A</scp> grobacterium tumefaciens </i> strains and possible application in plant transient transformation assays

Abstract

A grobacterium tumefaciens is a G ram‐negative bacterium. It causes plants to produce crown gall disease because of the transfer, integration and expression of oncogenes encoded by the T ‐ DNA (transferred DNA ) region of the tumour‐inducing ( T i) plasmid. A set of transferred genes directs the production of bacterial nutrients, called opines, formed by condensation of an amino acid and a keto acid or a sugar. Transformed cells synthesize and secrete substantial quantities of particular opines, which A . tumefaciens then uses as a carbon and sometimes nitrogen source. A grobacterium tumefaciens strains are usually classified on the basis of the opines they can catabolize. Because of the ability to transfer DNA between different kingdoms, A . tumefaciens is also frequently used to generate transgenic plants. This study analyses five poorly characterized wildtype A grobacterium strains, 1D1108, 1 D 1460, 1 D 132, 1 D 1478 and 1 D 1487, isolated from E uonymus , cane, cherry, S alix and apple, respectively. Partial T i‐plasmid sequence analysis demonstrated that the five strains harbour the nopaline‐type T i plasmid. Tumorigenesis and transient transformation assays of the five analysed and six wildtype A . tumefaciens strains were performed with selected plant species, including two or three species of B rassicaceae, A steraceae, S olanaceae, A piaceae and L eguminosae. The A . tumefaciens strains 1 D 1108, 1 D 1460 and 1 D 1478 showed higher transformation efficiencies than the previously characterized A . tumefaciens strains with several economically important crops. These data suggest the potential use of these newly characterized wildtype A . tumefaciens strains in transient transformation assays with certain plant species.