First report of causing bacteria wilt on eucalyptus in Brazil.

The Ralstonia solanacearum Species Complex (RSSC) is the most significant plant pathogen group with a wide host range. It is genetically related but displays distinct biological features, such as restrictive geography occurrence. The RSSC comprises three species: Ralstonia pseudosolanacearum (phylotype I and III), Ralstonia solanacearum (phylotype IIA and IIB), and Ralstonia syzygii (phylotype IV) (Fegan and Prior 2005).

Detection and molecular characterization of a novel mitovirus associated with Passiflora edulis Sims.

Mitoviruses are cryptic capsidless viruses belonging to the family Mitoviridae that replicate and are maintained in the mitochondria of fungi. Complete mitovirus-like sequences were recently assembled from plant transcriptome data and plant leaf tissue samples. Passion fruit (Passiflora spp.

Analysis of CRISPR-Cas loci distribution in Xanthomonas citri and its possible control by the quorum sensing system.

Xanthomonas is an important genus of plant-associated bacteria that causes significant yield losses of economically important crops worldwide. Different approaches have assessed genetic diversity and evolutionary interrelationships among the Xanthomonas species. However, information from clustered regularly interspaced short palindromic repeats (CRISPRs) has yet to be explored.

Drivers and consequences of bacteriophage host range.

Bacteriophages are obligate parasites of bacteria characterized by the breadth of hosts that they can infect. This "host range" depends on the genotypes and morphologies of the phage and the bacterial host, but also on the environment in which they are interacting. Understanding phage host range is critical to predicting the impacts of these parasites in their natural host communities and their utility as therapeutic agents, but is also key to predicting how phages evolve and in doing so drive evolutionary change in their host populations, including through movement of genes among unrelated bacterial genomes.

Changes to virus taxonomy and the ICTV Statutes ratified by the International Committee on Taxonomy of Viruses (2023).

This article reports changes to virus taxonomy and taxon nomenclature that were approved and ratified by the International Committee on Taxonomy of Viruses (ICTV) in April 2023. The entire ICTV membership was invited to vote on 174 taxonomic proposals that had been approved by the ICTV Executive Committee in July 2022, as well as a proposed revision of the ICTV Statutes. All proposals and the revised ICTV Statutes were approved by a majority of the voting membership.

Virus taxonomy and the role of the International Committee on Taxonomy of Viruses (ICTV).

The taxonomy of viruses is developed and overseen by the International Committee on Taxonomy of Viruses (ICTV), which scrutinizes, approves and ratifies taxonomic proposals, and maintains a list of virus taxa with approved names (https://ictv.global). The ICTV has approximately 180 members who vote by simple majority.

Four principles to establish a universal virus taxonomy.

A universal taxonomy of viruses is essential for a comprehensive view of the virus world and for communicating the complicated evolutionary relationships among viruses. However, there are major differences in the conceptualisation and approaches to virus classification and nomenclature among virologists, clinicians, agronomists, and other interested parties. Here, we provide recommendations to guide the construction of a coherent and comprehensive virus taxonomy, based on expert scientific consensus.

Abolishment of morphology-based taxa and change to binomial species names: 2022 taxonomy update of the ICTV bacterial viruses subcommittee.

This article summarises the activities of the Bacterial Viruses Subcommittee of the International Committee on Taxonomy of Viruses for the period of March 2021-March 2022. We provide an overview of the new taxa proposed in 2021, approved by the Executive Committee, and ratified by vote in 2022. Significant changes to the taxonomy of bacterial viruses were introduced: the paraphyletic morphological families Podoviridae, Siphoviridae, and Myoviridae as well as the order Caudovirales were abolished, and a binomial system of nomenclature for species was established.

Genomic Analysis Unveils the Pervasiveness and Diversity of Prophages Infecting Species.

Prophages are abundant elements integrated into bacterial genomes and contribute to inter-strain genetic variability and, in some cases, modulate the environmental behavior of bacteria, such as pathogen virulence. Here, we described prophage occurrence and diversity in publicly available genome assemblies, a genus containing plant pathogens. Prophage-like sequences were identified and taxonomically classified.

In through the Out Door: A Functional Virulence Factor Secretion System Is Necessary for Phage Infection in Ralstonia solanacearum.

Bacteriophages put intense selective pressure on microbes, which must evolve diverse resistance mechanisms to survive continuous phage attacks. We used a library of spontaneous acteriophage nsensitive utants (BIMs) to learn how the plant pathogen Ralstonia solanacearum resists the virulent lytic podophage phiAP1. Phenotypic and genetic characterization of many BIMs suggested that the R.

Differentiating between viruses and virus species by writing their names correctly.

Following the results of the International Committee on Taxonomy of Viruses (ICTV) Ratification Vote held in March 2021, a standard two-part "binomial nomenclature" is now the norm for naming virus species. Adoption of the new nomenclature is still in its infancy; thus, it is timely to reiterate the distinction between "virus" and "virus species" and to provide guidelines for naming and writing them correctly.

Characterization of a new mitovirus infecting the phytopathogenic fungus Microdochium albescens.

A novel mycovirus was identified infecting the phytopathogenic fungus Microdochium albescens. The characterized dsRNA segment, corresponding to the replicative intermediate of the mitovirus genome, is 2,562 base pairs (bp) in length, with an A+U content of 62.3%.

Genomic and Biological Characterization of Ralstonia solanacearum Inovirus Brazil 1, an Inovirus that Alters the Pathogenicity of the Phytopathogen Ralstonia pseudosolanacearum.

Filamentous bacteriophages contain a single-stranded DNA genome and have a peculiar lifestyle, since they do not cause host cell lysis, but establish a persistent association with the host, often causing behavioral changes, with effects on bacterial ecology. Over the years, a gradual reduction in the incidence of bacterial wilt has been observed in some fields from Brazil. This event, which has been associated with the loss of pathogenicity of Rasltonia spp.

Bacterial Viruses Subcommittee and Archaeal Viruses Subcommittee of the ICTV: update of taxonomy changes in 2021.

In this article, we - the Bacterial Viruses Subcommittee and the Archaeal Viruses Subcommittee of the International Committee on Taxonomy of Viruses (ICTV) - summarise the results of our activities for the period March 2020 - March 2021. We report the division of the former Bacterial and Archaeal Viruses Subcommittee in two separate Subcommittees, welcome new members, a new Subcommittee Chair and Vice Chair, and give an overview of the new taxa that were proposed in 2020, approved by the Executive Committee and ratified by vote in 2021. In particular, a new realm, three orders, 15 families, 31 subfamilies, 734 genera and 1845 species were newly created or redefined (moved/promoted).

Complete genome sequence of a recombinant isolate of yambean mosaic virus from Canavalia ensiformis.

The complete genome sequence of a Brazilian isolate of yambean mosaic virus (YBMV) is presented. High-throughput sequencing (Illumina HiSeq) and Sanger sequencing revealed the complete genome sequence of the YBMV-BRA-6 isolate, found in Canavalia ensiformis. The de novo contigs were assembled into a 9612 nucleotides (nt) long scaffold, excluding the 3'-terminal poly(A) tail, covering the complete genome.

Changes to virus taxonomy and to the International Code of Virus Classification and Nomenclature ratified by the International Committee on Taxonomy of Viruses (2021).

This article reports the changes to virus taxonomy approved and ratified by the International Committee on Taxonomy of Viruses (ICTV) in March 2021. The entire ICTV was invited to vote on 290 taxonomic proposals approved by the ICTV Executive Committee at its meeting in October 2020, as well as on the proposed revision of the International Code of Virus Classification and Nomenclature (ICVCN). All proposals and the revision were ratified by an absolute majority of the ICTV members.

Widespread distribution of prophages signaling the potential for adaptability and pathogenicity evolution of Ralstonia solanacearum species complex.

Integrated bacteriophages (prophages) can impact host cells, affecting their lifestyle, genomic diversity, and fitness. However, many basic aspects of how these organisms affect the host cell remain poorly understood. Ralstonia solanacearum is a gram-negative plant pathogenic bacterium that encompasses a great diversity of ecotypes regarded as a species complex (R.

Intra-host evolution of the ssDNA virus tomato severe rugose virus (ToSRV).

To evaluate and quantify the evolutionary dynamics of the bipartite begomovirus tomato severe rugose virus (ToSRV) in a cultivated and a non-cultivated host, plants of tomato and Nicandra physaloides were biolistically inoculated with an infectious clone and systemically infected leaves were sampled at 30, 75 and 120 days after inoculation. Total DNA was extracted and sequenced in the Illumina HiSeq 2000 platform. The datasets were trimmed with the quality score limit set to 0.

Taxonomy of prokaryotic viruses: 2018-2019 update from the ICTV Bacterial and Archaeal Viruses Subcommittee.

This article is a summary of the activities of the ICTV's Bacterial and Archaeal Viruses Subcommittee for the years 2018 and 2019. Highlights include the creation of a new order, 10 families, 22 subfamilies, 424 genera and 964 species. Some of our concerns about the ICTV's ability to adjust to and incorporate new DNA- and protein-based taxonomic tools are discussed.

Biological and molecular characterization of a bacteriophage infecting Xanthomonas campestris pv. campestris, isolated from brassica fields.

Xanthomonas campestris pv. campestris (Xcc) is the causal agent of black rot of crucifers. Here, we report a virus that infects Xcc isolated from brassica fields in Brazil.