Strain ATCC 4720T is the authentic type strain of Agrobacterium tumefaciens, which is not a later heterotypic synonym of Agrobacterium radiobacter

Transmission and Management of Pathogenic Agrobacterium tumefaciens and Rhodococcus fascians in Select Ornamentals

Pathogenic Agrobacterium tumefaciens and Rhodococcus fascians are phytobacteria that induce crown gall and leafy gall disease, respectively, resulting in undesirable growth abnormalities. When present in nurseries, plants infected by either bacterium are destroyed, resulting in substantial losses for growers, especially those producing plants valued for their ornamental attributes. There are many unanswered questions regarding pathogen transmission on tools used to take cuttings for propagation and whether products used for bacterial disease control are effective. We investigated the ability to transmit pathogenic A. tumefaciens and R. fascians on secateurs and the efficacy of registered control products against both bacteria in vitro and in vivo. Experimental plants used were Rosa × hybrida, Leucanthemum × superbum, and Chrysanthemum × grandiflorum for A. tumefaciens and Petunia × hybrida and Oenothera 'Siskiyou' with R. fascians. In separate experiments, we found secateurs could convey both bacteria in numbers sufficient to initiate disease in a host-dependent manner and that bacteria could be recovered from secateurs after a single cut through an infected stem. In in vivo assays, none of six products tested against A. tumefaciens prevented crown gall disease, although several products appeared promising in in vitro trials. Likewise, four compounds trialed against R. fascians failed to prevent disease. Sanitation and clean planting material remain the primary means of disease management.

Phylogenomics reveals insights into the functional evolution of the genus Agrobacterium and enables the description of Agrobacterium divergens sp. nov

The genus Agrobacterium was initially described as mainly phytopathogenic strains. Nowadays, the genus includes phytopathogenic and non-phytopathogenic bacteria that are distinctive among the Rhizobiaceae family. Recently we have isolated two closely related strains, LMG 31531^T and LMG 31532, from soil and plant roots, respectively. Both strains differ from previously reported species based on the genomic and phenotypic data. A. arsenijevicii KFB 330^T and A. fabacearum LMG 31642^T showed the highest 16S rRNA similarity (98.9 %), followed by A. nepotum LMG 26435^T (98.7 %). A clear genomic feature that distinguishes LMG 31531^T and LMG 31532 from other Agrobacterium species is the absence of a linear chromid. Nevertheless, typical values of the core-proteome Average Amino Acid Identity (cpAAI > 85 %) and 16S rRNA gene sequence similarity (>96 %) when compared to other members of the genus confirm the position of these two strains as part of the Agrobacterium genus. They are therefore described as Agrobacterium divergens sp. nov. Besides, our comparative genomic study and survey for clade-specific markers resulted in the discovery of conserved proteins that provide insights into the functional evolution of this genus.

Judicial Opinions 123-127

Opinion 123 places the epithet of the name Aeromonas punctata on the list of rejected epithets and clarifies the citation of authors of selected names within the genus Aeromonas. Opinion 124 denies the request to place Borreliella on the list of rejected names because the request is based on a misinterpretation of the Code, which is clarified. There are alternative ways to solve the perceived problem. Opinion 125 denies the request to place Lactobacillus fornicalis on the list of rejected names because the provided information does not yield a reason for rejection. Opinion 126 denies the request to place Prolinoborus and Prolinoborus fasciculus on the list of rejected names because a relevant type strain deposit was not examined. Opinion 127 grants the request to assign the strain deposited as ATCC 4720 as the type strain of Agrobacterium tumefaciens, thereby correcting the Approved Lists. These Opinions were ratified by the voting members of the International Committee on Systematics of Prokaryotes.

Judicial Commission of the International Committee on Systematics of Prokaryotes: Minutes of the Meeting on 27 July 2022

The minutes of the online meeting of the Judicial Commission of the International Committee on Systematics of Prokaryotes that was held on 27 July 2022 per video conference are presented.

International Committee on Systematics of Prokaryotes, Subcommittee on the taxonomy of Rhizobia and Agrobacteria, minutes of the annual meeting by videoconference, 5 July 2021, followed by online discussion until 31 December 2021

Minutes of the closed meeting of the International Committee on Systematics of Prokaryotes Subcommittee on the Taxonomy of Rhizobia and Agrobacteria held by videoconference, 5 July 2021, followed by online discussion until 31 December 2021, and list of recent species.