Rhizoviticin is an alphaproteobacterial tailocin that mediates biocontrol of grapevine crown gall disease.

Tailocins are headless phage tail structures that mediate interbacterial antagonism. Although the prototypical tailocins, R- and F-pyocins, in Pseudomonas aeruginosa, and other predominantly R-type tailocins have been studied, their presence in Alphaproteobacteria remains unexplored. Here, we report the first alphaproteobacterial F-type tailocin, named rhizoviticin, as a determinant of the biocontrol activity of Allorhizobium vitis VAR03-1 against crown gall. Rhizoviticin is encoded by a chimeric prophage genome, one providing transcriptional regulators and the other contributing to tail formation and cell lysis, but lacking head formation genes. The rhizoviticin genome retains a nearly intact early phage region containing an integrase remnant and replication-related genes critical for downstream gene transcription, suggesting an ongoing transition of this locus from a prophage to a tailocin-coding region. Rhizoviticin is responsible for the most antagonistic activity in VAR03-1 culture supernatant against pathogenic A. vitis strain, and rhizoviticin deficiency resulted in a significant reduction in the antitumorigenic activity in planta. We identified the rhizoviticin-coding locus in eight additional A. vitis strains from diverse geographical locations, highlighting a unique survival strategy of certain Rhizobiales bacteria in the rhizosphere. These findings advance our understanding of the evolutionary dynamics of tailocins and provide a scientific foundation for employing rhizoviticin-producing strains in plant disease control.

Complete Genome Sequence Data of Nonpathogenic and Nonantagonistic Strain of Rhizobium vitis VAR06-30 Isolated From Grapevine Rhizosphere.

Rhizobium (Agrobacterium) is one genus in the family Rhizobiaceae. Most of the species are epi- or endophytic bacteria which include tumorigenic or rhizogenic pathogens, root nodule bacteria, and commensal endosymbionts. Rhizobium vitis strain VAR06-30 is a commensal bacterium without pathogenicity which was isolated from a rootstock of grapevine in Japan. It also does not have antagonistic activity to the pathogenic strain of R. vitis. Here, we show the complete genome sequence data with annotation of R. vitis VAR06-30 which was analyzed by sequence reads obtained from both PacBio and Illumina platforms. This genome sequence would contribute to the understanding of evolutionary lineage and characteristics of Rhizobium commensal bacteria.[Formula: see text] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Complete Genome Sequence Data of Tumorigenic Rhizobium vitis Strain VAT03-9, a Causal Agent of Grapevine Crown Gall Disease.

Rhizobium vitis strain VAT03-9 (MAFF 211676) is a causal agent of crown gall disease in grapevine. It is one of the pathogenic strains of R. vitis isolated from graft unions of grapevine in Okayama Prefecture, Japan. Inoculation tests verified its virulence for gall formation on grapevine, tomato, and sunflower. It harbors tumor-inducing plasmid. Here, we present the complete genome sequence with annotation of R. vitis VAR03-9 obtained by assembling reads from PacBio and Illumina-sequencers. This genome sequence should be useful for the analyses of pathogenicity and evolutionary lineage of the pathogens of crown gall disease.[Formula: see text] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Complete Genome Sequence Data of Nonpathogenic Strain Rhizobium vitis VAR03-1, a Biological Control Agent for Grapevine Crown Gall Disease.

Crown gall disease in grapevine is caused by pathogenic strains of Rhizobium vitis with a tumor-inducing (Ti) plasmids. A nonpathogenic strain, VAR03-1 of R. vitis, has been isolated from the grapevine root of nursery stock and it was shown to act as a biological control agent to crown gall disease. Its disease-suppressive effect was observed even when it was coinoculated with the pathogen in a 1:1 ratio. Here, we present the complete genome data of R. vitis VAR03-1, assembled by sequencing reads obtained by both PacBio and Illumina technologies with annotation. This genome sequence could contribute to investigations of the molecular basis underlying the biocontrol activity as well as the root-colonization ability of this bacterial strain.[Formula: see text] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.