Relative frequency dynamics and loading of beet necrotic yellow vein virus genomic RNAs during the acquisition by its vector .

Unlabelled: The beet necrotic yellow vein virus (BNYVV) is a multipartite virus with the highest number (up to five) of genomic segments among RNA viruses. Classified as a soil-borne virus, it is persistently transmitted by the protozoan . Previous studies have demonstrated that the relative frequency of the BNYVV genomic RNAs was modified depending on the host plant as well as the infected organ, resulting in distinct stoichiometric ratios between the viral RNAs.

Arabidopsis RNA-binding proteins interact with viral structural proteins and modify turnip yellows virus accumulation.

As obligate intracellular parasites, viruses depend on host proteins and pathways for their multiplication. Among these host factors, specific nuclear proteins are involved in the life cycle of some cytoplasmic replicating RNA viruses, although their role in the viral cycle remains largely unknown. The polerovirus turnip yellows virus (TuYV) encodes a major coat protein (CP) and a 74 kDa protein known as the readthrough (RT) protein.

Rhizomania: Hide and Seek of and the Beet Necrotic Yellow Vein Virus with .

The molecular interactions between , the protist vector of sugar beet viruses, beet necrotic yellow vein virus (BNYVV), the causal agent of rhizomania, and have not been extensively studied. Here, the transmission of BNYVV to sugar beet by zoospores was optimized using genetically characterized organisms. Molecular interactions of aviruliferous and viruliferous protist infection on sugar beet were highlighted by transcriptomic analysis.

Hit two birds with one stone: the multiple properties of (viral) RNA silencing suppressors.

In any organism, gene expression regulation is provided by multiple factors to maintain a harmonious development of individuals. Discovered in the late 1990s, RNA interference (RNAi) completely remodelled the way in which gene expression regulations were initially apprehended. RNAi provides fine regulation at the cellular level and allows organisms to control their development, maintain their genomic integrity and fight against different stresses like viral infection.

[Hit two birds with one stone: the multiple properties of (viral) RNA silencing suppressors].

In any organism, gene expression regulation is provided by multiple factors to maintain a harmonious development of individuals. Discovered in the late 1990s, RNA interference (RNAi) completely remodelled the way in which gene expression regulations were initially apprehended. RNAi provides fine regulation at the cellular level and allows organisms to control their development, maintain their genomic integrity and fight against different stresses like viral infection.

[17 plant virology meeting report].

RVV Plant virology meeting (January 27-31, 2019, Aussois, France) allows researchers, engineers, technicians, students and post-docs to exchange around oral and poster presentations. These convivial meetings are 30 years old and have a nice future.

Long-distance movement of helical multipartite phytoviruses: keep connected or die?

All living organisms have to preserve genome integrity to ensure the survival of progeny generations. Viruses, though often regarded as 'non living', protect their nucleic acids from biotic and abiotic stresses, ranging from nuclease action to radiation-induced adducts. When the viral genome is split into multiple segments, preservation of at least one copy of each segment is required.

Massive up-regulation of LBD transcription factors and EXPANSINs highlights the regulatory programs of rhizomania disease.

Rhizomania of sugar beet, caused by Beet necrotic yellow vein virus (BNYVV), is characterized by excessive lateral root (LR) formation leading to dramatic reduction of taproot weight and massive yield losses. LR formation represents a developmental process tightly controlled by auxin signaling through AUX/IAA-ARF responsive module and LATERAL ORGAN BOUNDARIES DOMAIN (LBD) transcriptional network. Several LBD transcription factors play central roles in auxin-regulated LR development and act upstream of EXPANSINS (EXPs), cell wall (CW)-loosening proteins involved in plant development via disruption of the extracellular matrix for CW relaxation and expansion.

Beet Necrotic Yellow Vein Virus Noncoding RNA Production Depends on a 5'→3' Xrn Exoribonuclease Activity.

The RNA3 species of the beet necrotic yellow vein virus (BNYVV), a multipartite positive-stranded RNA phytovirus, contains the 'core' nucleotide sequence required for its systemic movement in . Within this 'core' sequence resides a conserved "coremin" motif of 20 nucleotides that is absolutely essential for long-distance movement. RNA3 undergoes processing steps to yield a noncoding RNA3 (ncRNA3) possessing "coremin" at its 5' end, a mandatory element for ncRNA3 accumulation.

Biological properties of Beet soil-borne mosaic virus and Beet necrotic yellow vein virus cDNA clones produced by isothermal in vitro recombination: Insights for reassortant appearance.

Two members of the Benyviridae family and genus Benyvirus, Beet soil-borne mosaic virus (BSBMV) and Beet necrotic yellow vein virus (BNYVV), possess identical genome organization, host range and high sequence similarity; they infect Beta vulgaris with variable symptom expression. In the US, mixed infections are described with limited information about viral interactions. Vectors suitable for agroinoculation of all genome components of both viruses were constructed by isothermal in vitro recombination.

Contributions and lessons learned from virology in contemporary biology.

Virology is a young discipline at the origin of discoveries that revolutionized our vision of biology. Often associated to pathological studies, this science raises more fundamental questions and brings molecular tools required for cellular manipulation. If viruses are considered as our enemies, they are used, sometimes as a last attempt, against multidrug resistant bacteria or to treat cancer.

ICTV Virus Taxonomy Profile: Virgaviridae.

The family Virgaviridae is a family of plant viruses with rod-shaped virions, a ssRNA genome with a 3'-terminal tRNA-like structure and a replication protein typical of alpha-like viruses. Differences in the number of genome components, genome organization and the mode of transmission provide the basis for genus demarcation. Tobacco mosaic virus (genus Tobamovirus) was the first virus to be discovered (in 1886); it is present in high concentrations in infected plants, is extremely stable and has been extensively studied.

ICTV Virus Taxonomy Profile: Benyviridae.

The Benyviridae is a family of multipartite plant viruses with rod-shaped virions. Genomes are segmented and comprised of single-stranded, positive-sense RNAs, each with a 5' m7G cap. Unlike rod-shaped viruses classified in the Virgaviridae family, the genome segments have a 3' polyA tract and there is post-translational cleavage of the viral replicase.

A Viral Noncoding RNA Complements a Weakened Viral RNA Silencing Suppressor and Promotes Efficient Systemic Host Infection.

Systemic movement of beet necrotic yellow vein virus (BNYVV) in Beta macrocarpa depends on viral RNA3, whereas in Nicotiana benthamiana this RNA is dispensable. RNA3 contains a coremin motif of 20 nucleotides essential for the stabilization of noncoding RNA3 (ncRNA3) and for long-distance movement in Beta species. Coremin mutants that are unable to accumulate ncRNA3 also do not achieve systemic movement in Beta species.

Ins and Outs of Multipartite Positive-Strand RNA Plant Viruses: Packaging versus Systemic Spread.

Viruses possessing a non-segmented genome require a specific recognition of their nucleic acid to ensure its protection in a capsid. A similar feature exists for viruses having a segmented genome, usually consisting of viral genomic segments joined together into one viral entity. While this appears as a rule for animal viruses, the majority of segmented plant viruses package their genomic segments individually.