The genus Agrobacterium was created a century ago by Conn who included it in the family Rhizobiaceae together with the genus Rhizobium. Initially, the genus Agrobacterium contained the non-pathogenic species Agrobacterium radiobacter and the plant pathogenic species Agrobacterium tumefaciens and Agrobacterium rhizogenes. At the end of the past century two new pathogenic species, Agrobacterium rubi and Agrobacterium vitis, were added to the genus. Already in the present century these species plus Agrobacterium larrymoorei were reclassified into genus Rhizobium. This reclassification was controversial and for a time both genus names were used when new species were described. Few years ago, after a taxonomic revision based on genomic data, the old species A. rhizogenes was maintained in the genus Rhizobium, the old species A. vitis was transferred to the genus Allorhizobium and several Rhizobium species were transferred to the genus Agrobacterium, which currently contains 14 species including the old species A. radiobacter, A. tumefaciens, A. rubi and A. larrymoorei. Most of these species are able to produce tumours in different plants, nevertheless the genus Agrobacterium also encompasses non-pathogenic species, one species able to nodulate legumes and one human pathogenic species. Taking into account that the species affiliations to five Agrobacterium genomospecies have not been determined yet, an increase in the number of species within this genus is expected in the near future.

属农杆菌是由康涅狄格州谁在家庭中包括它创造了一个世纪前根瘤菌与一起属根瘤菌。最初，农杆菌属包含非致病性种农杆菌，以及植物病原性根癌农杆菌和发根农杆菌。在上个世纪末，两个新的病原体，红宝石农杆菌和葡萄农杆菌被添加到该属中。在本世纪，这些物种与农杆菌属一起被重新归类为根瘤菌属（Rhizobium）。。这种重新分类是有争议的，并且一度在描述新物种时同时使用了两个属的名称。几年前，基于基因组数据的分类修订后，老品种的发根农杆菌维持属中的根瘤菌，老品种A.葡萄转移属Allorhizobium和几个根瘤菌物种转移属农杆菌，这目前包含14种，包括老种A. radiobacter，A. tumefaciens，A. rubi和A. larrymoorei。这些物种中的大多数能够在不同的植物中产生肿瘤，但是农杆菌属还包括非致病性物种，一种能够结节豆类的物种和一种人类致病物种。考虑到尚未确定与五种农杆菌属的种属关系，预计不久将来该属种的数量将增加。