ICTV Virus Taxonomy Profile: .

is a family of non-enveloped spherical viruses with dsRNA genomes of two linear segments, each of 7.2-8.9 kbp, comprising 16.

My Life and Virus Research Journey.

My long career in virology has been a continuous learning exercise with a very modest start. Virology and related pertinent fields have changed significantly during my lifetime. Sometimes I wish that my career had just started and I could apply all available and state of the art technology to solving problems and explaining intriguing observations.

ICTV Virus Taxonomy Profile: Quadriviridae.

The Quadriviridae is a monogeneric family of non-enveloped spherical viruses with quadripartite dsRNA genomes, each segment of 3.5-5.0 kbp, comprising 16.

Capsid Structure of dsRNA Fungal Viruses.

Most fungal, double-stranded (ds) RNA viruses lack an extracellular life cycle stage and are transmitted by cytoplasmic interchange. dsRNA mycovirus capsids are based on a 120-subunit T = 1 capsid, with a dimer as the asymmetric unit. These capsids, which remain structurally undisturbed throughout the viral cycle, nevertheless, are dynamic particles involved in the organization of the viral genome and the viral polymerase necessary for RNA synthesis.

ICTV Virus Taxonomy Profile: Hypoviridae.

The Hypoviridae, comprising one genus, Hypovirus, is a family of capsidless viruses with positive-sense, ssRNA genomes of 9.1-12.7 kb that possess either a single large ORF or two ORFs.

ICTV Virus Taxonomy Profile: Chrysoviridae.

The Chrysoviridae is a family of small, isometric, non-enveloped viruses (40 nm in diameter) with segmented dsRNA genomes (typically four segments). The genome segments are individually encapsidated and together comprise 11.5-12.

Acquisition of functions on the outer capsid surface during evolution of double-stranded RNA fungal viruses.

Unlike their counterparts in bacterial and higher eukaryotic hosts, most fungal viruses are transmitted intracellularly and lack an extracellular phase. Here we determined the cryo-EM structure at 3.7 Å resolution of Rosellinia necatrix quadrivirus 1 (RnQV1), a fungal double-stranded (ds)RNA virus.

ICTV Virus Taxonomy Profile: Partitiviridae.

The Partitiviridae is a family of small, isometric, non-enveloped viruses with bisegmented double-stranded (ds) RNA genomes of 3-4.8 kbp. The two genome segments are individually encapsidated.

Virus-mediated suppression of host non-self recognition facilitates horizontal transmission of heterologous viruses.

Non-self recognition is a common phenomenon among organisms; it often leads to innate immunity to prevent the invasion of parasites and maintain the genetic polymorphism of organisms. Fungal vegetative incompatibility is a type of non-self recognition which often induces programmed cell death (PCD) and restricts the spread of molecular parasites. It is not clearly known whether virus infection could attenuate non-self recognition among host individuals to facilitate its spread.

Heterodimers as the Structural Unit of the T=1 Capsid of the Fungal Double-Stranded RNA Rosellinia necatrix Quadrivirus 1.

Unlabelled: Most double-stranded RNA (dsRNA) viruses are transcribed and replicated in a specialized icosahedral capsid with a T=1 lattice consisting of 60 asymmetric capsid protein (CP) dimers. These capsids help to organize the viral genome and replicative complex(es). They also act as molecular sieves that isolate the virus genome from host defense mechanisms and allow the passage of nucleotides and viral transcripts.

Cooperative functioning between phenylalanine ammonia lyase and isochorismate synthase activities contributes to salicylic acid biosynthesis in soybean.

Salicylic acid (SA), an essential regulator of plant defense, is derived from chorismate via either the phenylalanine ammonia lyase (PAL) or the isochorismate synthase (ICS) catalyzed steps. The ICS pathway is thought to be the primary contributor of defense-related SA, at least in Arabidopsis. We investigated the relative contributions of PAL and ICS to defense-related SA accumulation in soybean (Glycine max).

Genomoviridae: a new family of widespread single-stranded DNA viruses.

Here, we introduce a new family of eukaryote-infecting single-stranded (ss) DNA viruses that was created recently by the International Committee on Taxonomy of Viruses (ICTV). The family, named Genomoviridae, contains a single genus, Gemycircularvirus, which currently has one recognized virus species, Sclerotinia gemycircularvirus 1. Sclerotinia sclerotiorum hypovirulence-associated DNA virus 1 (SsHADV-1) is currently the sole representative isolate of the family; however, a great number of SsHADV-1-like ssDNA virus genomes has been sequenced from various environmental, plant- and animal-associated samples, indicating that members of family Genomoviridae are widespread and abundant in the environment.

Reprint of "The victorivirus Helminthosporium victoriae virus 190S is the primary cause of disease/hypovirulence in its natural host and a heterologous host".

A transmissible disease of the plant pathogenic fungus Helminthosporium victoriae, the causal agent of Victoria blight of oats, was reported more than 50 years ago. Diseased, but not normal, isolates, of H. victoriae contain two distinct viruses designated according to their sedimentation values as victorivirus Helminthosporium victoriae virus 190S (HvV190S) and chrysovirus Helminthosporium victoriae 145S (HvV145S).

The victorivirus Helminthosporium victoriae virus 190S is the primary cause of disease/hypovirulence in its natural host and a heterologous host.

A transmissible disease of the plant pathogenic fungus Helminthosporium victoriae, the causal agent of Victoria blight of oats, was reported more than 50 years ago. Diseased, but not normal, isolates, of H. victoriae contain two distinct viruses designated according to their sedimentation values as victorivirus Helminthosporium victoriae virus 190S (HvV190S) and chrysovirus Helminthosporium victoriae 145S (HvV145S).

Characterization of a Novel Megabirnavirus from Sclerotinia sclerotiorum Reveals Horizontal Gene Transfer from Single-Stranded RNA Virus to Double-Stranded RNA Virus.

Unlabelled: Mycoviruses have been detected in all major groups of filamentous fungi, and their study represents an important branch of virology. Here, we characterized a novel double-stranded RNA (dsRNA) mycovirus, Sclerotinia sclerotiorum megabirnavirus 1 (SsMBV1), in an apparently hypovirulent strain (SX466) of Sclerotinia sclerotiorum. Two similarly sized dsRNA segments (L1- and L2-dsRNA), the genome of SsMBV1, are packaged in rigid spherical particles purified from strain SX466.

Ratification vote on taxonomic proposals to the International Committee on Taxonomy of Viruses (2015).

Changes to virus taxonomy approved and ratified by the International Committee on Taxonomy of Viruses in February 2015 are listed.

50-plus years of fungal viruses.

Mycoviruses are widespread in all major taxa of fungi. They are transmitted intracellularly during cell division, sporogenesis, and/or cell-to-cell fusion (hyphal anastomosis), and thus their life cycles generally lack an extracellular phase. Their natural host ranges are limited to individuals within the same or closely related vegetative compatibility groups, although recent advances have established expanded experimental host ranges for some mycoviruses.

An RNA cassette from Helminthosporium victoriae virus 190S necessary and sufficient for stop/restart translation.

Prototype victorivirus HvV190S employs stop/restart translation to express its RdRp from the downstream ORF in its bicistronic mRNA. The signals for this activity appear to include a predicted RNA pseudoknot directly upstream of the CP stop and RdRp start codons, which overlap in the motif AUGA. Here we used a dual-fluorescence system to further define which HvV190S sequences are important for stop/restart translation and found that the AUGA motif plus 38 nt directly upstream are both necessary and sufficient for this activity.

A novel partitivirus that confers hypovirulence on plant pathogenic fungi.

Unlabelled: Members of the family Partitiviridae have bisegmented double-stranded RNA (dsRNA) genomes and are not generally known to cause obvious symptoms in their natural hosts. An unusual partitivirus, Sclerotinia sclerotiorum partitivirus 1 (SsPV1/WF-1), conferred hypovirulence on its natural plant-pathogenic fungal host, Sclerotinia sclerotiorum strain WF-1. Cellular organelles, including mitochondria, were severely damaged.

Cryo-EM near-atomic structure of a dsRNA fungal virus shows ancient structural motifs preserved in the dsRNA viral lineage.

Viruses evolve so rapidly that sequence-based comparison is not suitable for detecting relatedness among distant viruses. Structure-based comparisons suggest that evolution led to a small number of viral classes or lineages that can be grouped by capsid protein (CP) folds. Here, we report that the CP structure of the fungal dsRNA Penicillium chrysogenum virus (PcV) shows the progenitor fold of the dsRNA virus lineage and suggests a relationship between lineages.

Taxonomic reorganization of family Partitiviridae and other recent progress in partitivirus research.

Phylogenetic analyses have prompted a taxonomic reorganization of family Partitiviridae (encapsidated, bisegmented dsRNA viruses that infect plants, fungi, or protozoa), the focus of this review. After a brief introduction to partitiviruses, the taxonomic changes are discussed, including replacement of former genera Partitivirus, Alphacryptovirus, and Betacryptovirus, with new genera Alphapartitivirus, Betapartitivirus, Gammapartitivirus, and Deltapartitivirus, as well as redistribution of species among these new genera. To round out the review, other recent progress of note in partitivirus research is summarized, including discoveries of novel partitivirus sequences by metagenomic approaches and mining of sequence databases, determinations of fungal partitivirus particle structures, demonstrations of fungal partitivirus transmission to new fungal host species, evidence for other aspects of partitivirus-host interactions and host effects, and identification of other fungal or plant viruses with some similarities to partitiviruses.

Complete genome sequence of a novel hypovirus infecting Phomopsis longicolla.

The complete nucleotide sequence and genome organization of a hypovirus from the isolate ME711 of Phomopsis longicolla was determined and compared to sequences of members of the family Hypoviridae. The genome of the hypovirus, tentatively named Phomopsis longicolla hypovirus 1 (PlHV1-ME711), was determined to be 9760 nucleotides long, excluding the 3' poly (A) tail. The genome contains a single large open reading frame (ORF) encoding a polyprotein designated as P307.

Overexpression of GmCaM4 in soybean enhances resistance to pathogens and tolerance to salt stress.

Plant diseases inflict heavy losses on soybean yield, necessitating an understanding of the molecular mechanisms underlying biotic/abiotic stress responses. Ca(2) (+) is an important universal messenger, and protein sensors, prominently calmodulins (CaMs), recognize cellular changes in Ca(2) (+) in response to diverse signals. Because the development of stable transgenic soybeans is laborious and time consuming, we used the Bean pod mottle virus (BPMV)-based vector for rapid and efficient protein expression and gene silencing.

Nodulin 22, a novel small heat-shock protein of the endoplasmic reticulum, is linked to the unfolded protein response in common bean.

The importance of plant small heat shock proteins (sHsp) in multiple cellular processes has been evidenced by their unusual abundance and diversity; however, little is known about their biological role. Here, we characterized the in vitro chaperone activity and subcellular localization of nodulin 22 of Phaseolus vulgaris (PvNod22; common bean) and explored its cellular function through a virus-induced gene silencing-based reverse genetics approach. We established that PvNod22 facilitated the refolding of a model substrate in vitro, suggesting that it acts as a molecular chaperone in the cell.