Agrobacterium radiobacter

Agrobacterium radiobacter is the type species of the genus Agrobacterium, a genus of Gram-negative bacteria that cause tumors in plants. It was incorrectly synonymized with Agrobacterium tumefaciens until 2022. This species is widely found in soil, in plant rhizospheres, and in human clinical specimens. Some members such as B6 harbor a tumor-inducing (Ti) plasmid and cause crown gall disease in plants. The type strain ATCC 19358 does not carry such a plasmid and is nonpathogenic.

The incorrect synonimization with A. tumefaciens was due to a strain B6 (ATCC 23308) being assigned as the type strain of A. tumefaciens in 1980, when B6 should be classified as A. radiobacter. One consequence is that this B6 strain is very well-studied in the lab. Another consequence is that research done on "A. tumefaciens" between 1980 and 2022 are possibly describing A. radiobacter instead. To determine the actual species, one should look up the 16S or genomic sequences of the strain used in the study.