Agrobacterium tumefaciens KAT23 harbors a nopaline-type Ti plasmid and is "super-virulent" to soybean (Glycine max) and other leguminous plants. The right and left border sequences of the essential cis-element for T-DNA transfer were removed in order to utilize the high infectivity of this strain in an Agrobacterium-mediated soybean transformation system. The resulting strain, named Soy2, showed no oncogenic activity. After inoculation with disarmed Soy2 harboring binary vector pIG121-Hm and pCAMBIA-WR, soybean epicotyls exhibited high beta-glucuronidase activities, with efficiencies higher than EHA105, an A. tumefaciens strain widely used in making transgenic plants.