International Committee on Systematics of Prokaryotes: Subcommittee on the taxonomy of Agrobacterium and Rhizobium

This document presents the minutes from a July 2001 meeting of the International Committee on Systematics of Prokaryotes Subcommittee on Agrobacterium and Rhizobium taxonomy held in Hamilton, Canada. The committee discussed its evolving role, shifting from primarily reviewing new species to providing taxonomy guidelines and fostering scientific discussion. Key topics included establishing a website for rhizobial taxonomy discussions, defining terminology for nodulating bacteria discovered outside traditional genera (such as Burkholderia and Methylobacterium), and reviewing newly described species including Agrobacterium larrymoorei, Mesorhizobium chacoense, and Sinorhizobium species. The committee noted Young et al.'s proposal to merge Agrobacterium and Rhizobium genera, recommending scientists remain informed while allowing the community to choose preferred nomenclature. Additionally, the committee addressed the taxonomic relationship between Sinorhizobium and Ensifer genera, noting they represent a single taxon and indicating plans to petition the Judicial Commission regarding priority naming under bacteriological code rules.

Key findings

• The committee's focus shifted from species review to developing taxonomy guidelines and providing discussion forums for the scientific community
• Nodulating bacteria from β-subclass Proteobacteria (Burkholderia, Methylobacterium) raised questions about defining 'rhizobia' terminology
• Young et al. proposed merging Agrobacterium and Rhizobium genera, with nomenclature updates appearing in bacterial name databases
• Sinorhizobium and Ensifer represent a single taxon, requiring the committee to petition the Judicial Commission regarding naming priority
• Multiple new Agrobacterium, Mesorhizobium, and Sinorhizobium species were described since the previous meeting