Faculty Profiles - SUZUKI Nobuhiro

Papers - SUZUKI Nobuhiro

Division display 1 - 20 of about 181 ／ All the affair displays >>

RNA editing of genomic neighbors controls antiviral response in fungi

Shinji Honda, Ayumi Yokoyama, Nobuhiro Suzuki

Cell Host & Microbe 2025.3

Argonaute-independent, Dicer-dependent antiviral defense against RNA viruses. Reviewed International journal

Yukiyo Sato, Hideki Kondo, Nobuhiro Suzuki

Proceedings of the National Academy of Sciences of the United States of America 121 ( 25 ) e2322765121 2024.6

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

Antiviral RNA interference (RNAi) is conserved from yeasts to mammals. Dicer recognizes and cleaves virus-derived double-stranded RNA (dsRNA) and/or structured single-stranded RNA (ssRNA) into small-interfering RNAs, which guide effector Argonaute to homologous viral RNAs for digestion and inhibit virus replication. Thus, Argonaute is believed to be essential for antiviral RNAi. Here, we show Argonaute-independent, Dicer-dependent antiviral defense against dsRNA viruses using Cryphonectria parasitica (chestnut blight fungus), which is a model filamentous ascomycetous fungus and hosts a variety of viruses. The fungus has two dicer-like genes (dcl1 and dcl2) and four argonaute-like genes (agl1 to agl4). We prepared a suite of single to quadruple agl knockout mutants with or without dcl disruption. We tested these mutants for antiviral activities against diverse dsRNA viruses and ssRNA viruses. Although both DCL2 and AGL2 worked as antiviral players against some RNA viruses, DCL2 without argonaute was sufficient to block the replication of other RNA viruses. Overall, these results indicate the existence of a Dicer-alone defense and different degrees of susceptibility to it among RNA viruses. We discuss what determines the great difference in susceptibility to the Dicer-only defense.

DOI： 10.1073/pnas.2322765121

Replication of single viruses across the kingdoms, Fungi, Plantae, and Animalia. Reviewed International journal

Paul Telengech, Kiwamu Hyodo, Hiroaki Ichikawa, Ryusei Kuwata, Hideki Kondo, Nobuhiro Suzuki

Proceedings of the National Academy of Sciences of the United States of America 121 ( 25 ) e2318150121 2024.6

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

It is extremely rare that a single virus crosses host barriers across multiple kingdoms. Based on phylogenetic and paleovirological analyses, it has previously been hypothesized that single members of the family Partitiviridae could cross multiple kingdoms. Partitiviridae accommodates members characterized by their simple bisegmented double-stranded RNA genome; asymptomatic infections of host organisms; the absence of an extracellular route for entry in nature; and collectively broad host range. Herein, we show the replicability of single fungal partitiviruses in three kingdoms of host organisms: Fungi, Plantae, and Animalia. Betapartitiviruses of the phytopathogenic fungusRosellinia necatrix could replicate in protoplasts of the carrot (Daucus carota), Nicotiana benthamiana and Nicotiana tabacum, in some cases reaching a level detectable by agarose gel electrophoresis. Moreover, betapartitiviruses showed more robust replication than the tested alphapartitiviruses. One of the fungal betapartitiviruses, RnPV18, could persistently and stably infect carrot plants regenerated from virion-transfected protoplasts. Both alpha- and betapartitiviruses, although with different host preference, could replicate in two insect cell lines derived from the fall armyworm Spodoptera frugiperda and the fruit fly Drosophila melanogaster. Our results indicate the replicability of single partitiviruses in members of three kingdoms and provide insights into virus adaptation, host jumping, and evolution.

DOI： 10.1073/pnas.2318150121

Three-Layered Complex Interactions among Capsidless (+)ssRNA Yadokariviruses, dsRNA Viruses, and a Fungus Reviewed

Yukiyo Sato, Sakae Hisano, Carlos José López-Herrera, Hideki Kondo, Nobuhiro Suzuki

mBio 2022.8

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：American Society for Microbiology

A capsidless (+)ssRNA virus YkV1 (family Yadokariviridae ) highjacks the capsid of an unrelated dsRNA virus YnV1 (proposed family “ Yadonushiviridae ”) in a phytopathogenic ascomycete, while YkV1 trans -enhances YnV1 replication. Herein, we identified the dsRNA virus partners of three yadokariviruses (YkV3, YkV4a, and YkV4b) with genome organization different from YkV1 as being different from YnV1 at the suborder level.

DOI： 10.1128/mbio.01685-22

Mycovirus Diversity and Evolution Revealed/Inferred from Recent Studies. International journal

Hideki Kondo, Leticia Botella, Nobuhiro Suzuki

Annual review of phytopathology 2022.5

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)

High-throughput virome analyses with various fungi, from cultured or uncultured sources, have led to the discovery of diverse viruses with unique genome structures and even neo-lifestyles. Examples in the former category include splipalmiviruses and ambiviruses. Splipalmiviruses, related to yeast narnaviruses, have multiple positive-sense (+) single-stranded (ss) RNA genomic segments that separately encode the RNA-dependent RNA polymerase motifs, the hallmark of RNA viruses (members of the kingdom Orthornavirae). Ambiviruses appear to have an undivided ssRNA genome of 3∼5 kb with two large open reading frames (ORFs) separated by intergenic regions. Another narna-like virus group has two fully overlapping ORFs on both strands of a genomic segment that span more than 90% of the genome size. New virus lifestyles exhibited by mycoviruses include the yado-kari/yado-nushi nature characterized by the partnership between the (+)ssRNA yadokarivirus and an unrelated dsRNA virus (donor of the capsid for the former) and the hadaka nature of capsidless 10-11 segmented (+)ssRNA accessible by RNase in infected mycelial homogenates. Furthermore, dsRNA polymycoviruses with phylogenetic affinity to (+)ssRNA animal caliciviruses have been shown to be infectious as dsRNA-protein complexes or deproteinized naked dsRNA. Many previous phylogenetic gaps have been filled by recently discovered fungal and other viruses, which have provided interesting evolutionary insights. Phylogenetic analyses and the discovery of natural and experimental cross-kingdom infections suggest that horizontal virus transfer may have occurred and continue to occur between fungi and other kingdoms. Expected final online publication date for the Annual Review of Phytopathology, Volume 60 is August 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

DOI： 10.1146/annurev-phyto-021621-122122

Proof of concept of the Yadokari nature: A capsidless replicase-encoding but replication-dependent positive-sense single-stranded RNA virus hosted by an unrelated double-stranded RNA virus Reviewed

Subha Das, Md Mahfuz Alam, Rui Zhang, Sakae Hisano, Nobuhiro Suzuki

Journal of Virology 95 ( 17 ) e00467-21 2021.9

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)

We previously proposed a new virus lifestyle or yadokari/yadonushi nature exhibited by a positive-sense single-stranded RNA (ssRNA) virus, yadokari virus 1 (YkV1), and an unrelated double-stranded RNA (dsRNA) virus, yadonushi virus 1 (YnV1) in a phytopathogenic ascomycete, Rosellinia necatrix. We have proposed that YkV1 diverts the YnV1 capsid to trans-encapsidate YkV1 RNA and RNA-dependent RNA polymerase (RdRp) and replicate in the heterocapsid. However, it remains uncertain whether YkV1 replicates using its own RdRp and whether YnV1 capsid copackages both YkV1 and YnV1 components. To address these questions, we first took advantage of the reverse genetics tools available for YkV1. Mutations in the GDD RdRp motif, one of the two identifiable functional motifs in the YkV1 polyprotein, abolished its replication competency. Mutations were also introduced in the conserved 2A-like peptide motif, hypothesized to cleave the YkV1 polyprotein cotranslationally. Interestingly, the replication proficiency of YkV1 mutants in the host fungus agreed with the cleavage activity of the 2A-like peptide tested using a baculovirus expression system. Cesium chloride equilibrium density gradient centrifugation allowed for the separation of particles, with a subset of YnV1 capsids solely packaging YkV1 dsRNA and RdRp. These results provide proof of concept that a capsidless positive-sense ssRNA [(1)ssRNA] virus is hosted by an unrelated dsRNA virus. IMPORTANCE Viruses typically encode their own capsids that encase their genomes. However, a capsidless positive-sense single-stranded RNA [(1)ssRNA] virus, YkV1, depends on an unrelated double-stranded RNA (dsRNA) virus, YnV1, for encapsidation and replication. We previously showed that YkV1 highjacks the capsid of YnV1 for trans-encapsidation of its own RNA and RdRp. YkV1 was hypothesized to divert the heterocapsid as the replication site, as is commonly observed for dsRNA viruses. Herein, mutational analyses showed that the RdRp and 2A-like domains of the YkV1 polyprotein are important for its replication. The active RdRp must be cleaved by a 2A-like peptide from the C-proximal protein. Cesium chloride equilibrium density gradient centrifugation allowed for the separation of particles, with YnV1 capsids solely packaging YkV1 dsRNA and RdRp. This study provides proof of concept of a virus neo-lifestyle where a (1)ssRNA virus snatches capsids from an unrelated dsRNA virus to replicate with its own RdRp, thereby mimicking the typical dsRNA virus lifestyle.

DOI： 10.1128/JVI.00467-21

Establishment of Neurospora crassa as a model organism for fungal virology Reviewed

Shinji Honda, Ana Eusebio-Cope, Shuhei Miyashita, Ayumi Yokoyama, Annisa Aulia, Sabitree Shahi, Hideki Kondo, Nobuhiro Suzuki

Nature Communications 11 ( 1 ) 5627 2020.12

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)

The filamentous fungus Neurospora crassa is used as a model organism for genetics, developmental biology and molecular biology. Remarkably, it is not known to host or to be susceptible to infection with any viruses. Here, we identify diverse RNA viruses in N. crassa and other Neurospora species, and show that N. crassa supports the replication of these viruses as well as some viruses from other fungi. Several encapsidated double-stranded RNA viruses and capsid-less positive-sense single-stranded RNA viruses can be experimentally introduced into N. crassa protoplasts or spheroplasts. This allowed us to examine viral replication and RNAi-mediated antiviral responses in this organism. We show that viral infection upregulates the transcription of RNAi components, and that Dicer proteins (DCL-1, DCL-2) and an Argonaute (QDE-2) participate in suppression of viral replication. Our study thus establishes N. crassa as a model system for the study of host-virus interactions.

DOI： 10.1038/s41467-020-19355-y

Hadaka virus 1: A capsidless eleven-segmented positive-sense single-stranded RNA virus from a phytopathogenic fungus, Fusarium oxysporum Reviewed International journal

Yukiyo Sato, Wajeeha Shamsi, Atif Jamal, Muhammad Faraz Bhatti, Hideki Kondo, Nobuhiro Suzuki, Reed B. Wickner

mBio 11 ( 3 ) e0045-20 2020.5

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)

The search for viruses infecting fungi, or mycoviruses, has extended our knowledge about the diversity of RNA viruses, as exemplified by the discovery of polymycoviruses, a phylogenetic group of multisegmented RNA viruses with unusual forms. The genomic RNAs of known polymycoviruses, which show a phylogenetic affinity for animal positive-sense single-stranded RNA [(+)RNA] viruses such as caliciviruses, are comprised of four conserved segments with an additional zero to four segments. The double-stranded form of polymycovirus genomic RNA is assumed to be associated with a virally encoded protein (proline-alanine-serine-rich protein [PASrp]) in either of two manners: a capsidless colloidal form or a filamentous encapsidated form. Detailed molecular characterizations of polymycoviruses, however, have been conducted for only a few strains. Here, a novel polymyco-related virus named Hadaka virus 1 (HadV1), from the phytopathogenic fungus Fusarium oxysporum, was characterized. The genomic RNA of HadV1 consisted of an 11-segmented positive-sense RNA with highly conserved terminal nucleotide sequences. HadV1 shared the three conserved segments with known polymycoviruses but lacked the PASrp-encoding segment. Unlike the known polymycoviruses and encapsidated viruses, HadV1 was not pelleted by conventional ultracentrifugation, possibly due to the lack of PASrp. This result implied that HadV1 exists only as a soluble form with naked RNA. Nevertheless, the 11 genomic segments of HadV1 have been stably maintained through host subculturing and conidiation. Taken together, the results of this study revealed a virus with a potential novel virus lifestyle, carrying many genomic segments without typical capsids or PASrp-associated forms. IMPORTANCE Fungi collectively host various RNA viruses. Examples include encapsidated double-stranded RNA (dsRNA) viruses with diverse numbers of genomic segments (from 1 to 12) and capsidless viruses with nonsegmented (+)RNA genomes. Recently, viruses with unusual intermediate features of an infectious entity between encapsidated dsRNA viruses and capsidless (+)RNA viruses were found. They are called polymycoviruses, which typically have four to eight dsRNA genomic segments associated with one of the virus-encoded proteins and are phylogenetically distantly related to animal (+)RNA caliciviruses. Here, we identified a novel virus phylogenetically related to polymycoviruses, from the phytopathogenic fungus Fusarium oxysporum. The virus, termed Hadaka virus 1 (HadV1), has 11 (+)RNA genomic segments, the largest number in known (+)RNA viruses. Nevertheless, HadV1 lacked a typical structural protein of polymycoviruses and was not pelleted by standard ultracentrifugation, implying an unusual capsidless nature of HadV1. This study reveals a potential novel lifestyle of multisegmented RNA viruses.

DOI： 10.1128/mBio.00450-20

Dicer functions transcriptionally and posttranscriptionally in a multilayer antiviral defense. Reviewed

Andika IB, Kondo H, Suzuki N

Proceedings of the National Academy of Sciences of the United States of America 116 ( 6 ) 2274 - 2281 2019.2

SAGA complex mediates the transcriptional up-regulation of antiviral RNA silencing Reviewed

Ida Bagus Andika, Atif Jamal, Hideki Kondo, Nobuhiro Suzuki

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 114 ( 17 ) E3499 - E3506 2017.4

Language：English Publishing type：Research paper (scientific journal) Publisher：NATL ACAD SCIENCES

Pathogen recognition and transcriptional activation of defense-related genes are crucial steps in cellular defense responses. RNA silencing (RNAi) functions as an antiviral defense in eukaryotic organisms. Several RNAi-related genes are known to be transcriptionally up-regulated upon virus infection in some host organisms, but little is known about their induction mechanism. A phytopathogenic ascomycete, Cryphonectria parasitica (chestnut blight fungus), provides a particularly advantageous system to study RNAi activation, because its infection by certain RNA viruses induces the transcription of dicer-like 2 (dcl2) and argonaute-like 2 (agl2), two major RNAi players. To identify cellular factors governing activation of antiviral RNAi in C. parasitica, we developed a screening protocol entailing multiple transformations of the fungus with cDNA of a hypovirus mutant lacking the RNAi suppressor (CHV1-Delta p69), a reporter construct with a GFP gene driven by the dcl2 promoter, and a random mutagenic construct. Screening for GFP-negative colonies allowed the identification of sgf73, a component of the SAGA (Spt-Ada-Gcn5 acetyltransferase) complex, a well-known transcriptional coactivator. Knockout of other SAGA components showed that the histone acetyltransferase module regulates transcriptional induction of dcl2 and agl2, whereas histone deubiquitinase mediates regulation of agl2 but not dcl2. Interestingly, full-scale induction of agl2 and dcl2 by CHV1 Delta p69 required both DCL2 and AGL2, whereas that by another RNA virus, mycoreovirus 1, required only DCL2, uncovering additional roles for DCL2 and AGL2 in viral recognition and/or RNAi activation. Overall, these results provide insight into the mechanism of RNAi activation.

DOI： 10.1073/pnas.1701196114

Harnessing host ROS-generating machinery for the robust genome replication of a plant RNA virus Reviewed

Kiwamu Hyodo, Kenji Hashimoto, Kazuyuki Kuchitsu, Nobuhiro Suzuki, Tetsuro Okuno

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 114 ( 7 ) E1282 - E1290 2017.2

Language：English Publishing type：Research paper (scientific journal) Publisher：NATL ACAD SCIENCES

As sessile organisms, plants have to accommodate to rapid changes in their surrounding environment. Reactive oxygen species (ROS) act as signaling molecules to transduce biotic and abiotic stimuli into plant stress adaptations. It is established that a respiratory burst oxidase homolog B of Nicotiana benthamiana (NbRBOHB) produces ROS in response to microbe-associated molecular patterns to inhibit pathogen infection. Plant viruses are also known as causative agents of ROS induction in infected plants; however, the function of ROS in plant-virus interactions remains obscure. Here, we show that the replication of red clover necrotic mosaic virus (RCNMV), a plant positive-strand RNA [(+) RNA] virus, requires NbRBOHB-mediated ROS production. The RCNMV replication protein p27 plays a pivotal role in this process, redirecting the subcellular localization of NbRBOHB and a subgroup II calcium-dependent protein kinase of N. benthamiana (NbCDPKiso2) from the plasma membrane to the p27-containing intracellular aggregate structures. p27 also induces an intracellular ROS burst in an RBOH-dependent manner. NbCDPKiso2 was shown to be an activator of the p27-triggered ROS accumulations and to be required for RCNMV replication. Importantly, this RBOH-derived ROS is essential for robust viral RNA replication. The need for RBOHderived ROS was demonstrated for the replication of another (+) RNA virus, brome mosaic virus, suggesting that this characteristic is true for plant (+) RNA viruses. Collectively, our findings revealed a hitherto unknown viral strategy whereby the host ROS-generating machinery is diverted for robust viral RNA replication.

DOI： 10.1073/pnas.1610212114

A capsidless ssRNA virus hosted by an unrelated dsRNA virus Reviewed

Rui Zhang, Sakae Hisano, Akio Tani, Hideki Kondo, Satoko Kanematsu, Nobuhiro Suzuki

Nature Microbiology 1 ( 1 ) 2016.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Nature Publishing Group

Viruses typically encode the capsid that encases their genome, while satellite viruses do not encode a replicase and depend on a helper virus for their replication 1. Here, we report interplay between two RNA viruses, yado-nushi virus 1 (YnV1) and yado-kari virus 1 (YkV1), in a phytopathogenic fungus, Rosellinia necatrix2. YkV1 has a close phylogenetic affinity to positive-sense, single-stranded (+)ssRNA viruses such as animal caliciviruses3, while YnV1 has an undivided double-stranded (ds) RNA genome with a resemblance to fungal totiviruses4. Virion transfection and infectious full-length cDNA transformation has shown that YkV1 depends on YnV1 for viability, although it probably encodes functional RNA-dependent RNA polymerase (RdRp). Immunological and molecular analyses have revealed trans-encapsidation of not only YkV1 RNA but also RdRp by the capsid protein of the other virus (YnV1), and enhancement of YnV1 accumulation by YkV1. This study demonstrates interplay in which the capsidless (+)ssRNA virus (YkV1), hijacks the capsid protein of the dsRNA virus (YnV1), and replicates as if it were a dsRNA virus.

DOI： 10.1038/nmicrobiol.2015.1

Highly activated RNA silencing via strong induction of dicer by one virus can interfere with the replication of an unrelated virus Reviewed

Sotaro Chiba, Nobuhiro Suzuki

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 112 ( 35 ) E4911 - E4918 2015.9

Language：English Publishing type：Research paper (scientific journal) Publisher：NATL ACAD SCIENCES

Viruses often coinfect single host organisms in nature. Depending on the combination of viruses in such coinfections, the interplay between them may be synergistic, apparently neutral with no effect on each other, or antagonistic. RNA silencing is responsible for many cases of interference or cross-protection between viruses, but such antagonistic interactions are usually restricted to closely related strains of the same viral species. In this study, we present an unprecedented example of RNA silencing-mediated one-way interference between unrelated viruses in a filamentous model fungus, Cryphonectria parasitica. The replication of Rosellinia necatrix victorivirus 1 (RnVV1; Totiviridae) was strongly impaired by coinfection with the prototypic member of the genus Mycoreovirus (MyRV1) or a mutant of the prototype hypovirus (Cryphonectria hypovirus 1, CHV1) lacking the RNA silencing suppressor (CHV1-Delta p69). This interference was associated with marked transcriptional induction of key genes in antiviral RNA silencing, dicer-like 2 (dcl2) and argonaute-like 2 (agl2), following MyRV1 or CHV1-Delta p69 infection. Interestingly, the inhibition of RnVV1 replication was reproduced when the levels of dcl2 and agl2 transcripts were elevated by transgenic expression of a hairpin construct of an endogenous C. parasitica gene. Disruption of dcl2 completely abolished the interference, whereas that of agl2 did not always lead to its abolishment, suggesting more crucial roles of dcl2 in antiviral defense. Taken altogether, these results demonstrated the susceptible nature of RnVV1 to the antiviral silencing in C. parasitica activated by distinct viruses or transgene-derived double-stranded RNAs and provide insight into the potential for broad-spectrum virus control mediated by RNA silencing.

DOI： 10.1073/pnas.1509151112

Mycoreovirus genome rearrangements associated with RNA silencing deficiency Reviewed

Ana Eusebio-Cope, Nobuhiro Suzuki

NUCLEIC ACIDS RESEARCH 43 ( 7 ) 3802 - 3813 2015.4

Language：English Publishing type：Research paper (scientific journal) Publisher：OXFORD UNIV PRESS

Mycoreovirus 1 (MyRV1) has 11 double-stranded RNA genome segments (S1 to S11) and confers hypovirulence to the chestnut blight fungus, Cryphonectria parasitica. MyRV1 genome rearrangements are frequently generated by a multifunctional protein, p29, encoded by a positive-strand RNA virus, Cryphonectria hypovirus 1. One of its functional roles is RNA silencing suppression. Here, we explored a possible link between MyRV1 genome rearrangements and the host RNA silencing pathway using wild-type (WT) and mutant strains of both MyRV1 and the host fungus. Host strains included deletion mutants of RNA silencing components such as dicer-like (dcl) and argonaute-like (agl) genes, while virus strains included an S4 internal deletion mutant MyRV1/S4ss. Consequently, intragenic rearrangements with nearly complete duplication of the three largest segments, i.e. S1, S2 and S3, were observed even more frequently in the RNA silencing-deficient strains Delta dcl2 and Delta agl2 infected with MyRV1/S4ss, but not with any other viral/host strain combinations. An interesting difference was noted between genome rearrangement events in the two host strains, i.e. generation of the rearrangement required prolonged culture for Delta agl2 in comparison with Delta dcl2. These results suggest a role for RNA silencing that suppresses genome rearrangements of a dsRNA virus.

DOI： 10.1093/nar/gkv239

A capsidless (+)RNA yadokarivirus hosted by a dsRNA virus is infectious as particles, cDNA, and dsRNA. International journal

Muhammad Fadli, Sakae Hisano, Guy Novoa, José R Castón, Hideki Kondo, Nobuhiro Suzuki

Journal of virology 99 ( 3 ) e0216624 2025.3

Language：English Publishing type：Research paper (scientific journal)

Capsidless yadokariviruses (members of the order Yadokarivirales) with (+)RNA genomes divert the capsid of their partner icosahedral double-stranded RNA (dsRNA) viruses in different families of the order Ghabrivirales into the replication site. A yadokarivirus, AfSV2, has been reported from a German strain of the ascomycete fungus Aspergillus foetidus coinfected by two dsRNA viruses, a victorivirus (AfSV1, family Pseudototiviridae) and an alternavirus (AfFV, family Alternaviridae). Here, we identified AfSV1 as the partner of AfSV2 in a Japanese A. foetidus strain after showing the infectiousness of AfSV2 in three forms: virus particles (heterocapsid), transforming full-length complementary DNA (cDNA), and purified replicated form (RF) dsRNA that is believed to be inactive as a translational template. Virion transfection of virus-free A. foetidus protoplasts resulted in the generation of two strains infected either by AfSV1 alone or by both AfSV1 and AfSV2. Transformants with AfSV2 full-length cDNA launched AfSV2 infection only in the presence of AfSV1, but not those with AfSV2 RNA-directed RNA polymerase mutant cDNA. The purified fractions containing AfSV2 RF dsRNA also launched infection when transfected into protoplasts infected by AfSV1. Treatment with dsRNA-specific RNase III, but not with proteinase K, S1 nuclease, or DNase I, abolished the infectivity of AfSV2 RF dsRNA. Furthermore, we confirmed the infectiousness of gel-purified AfSV2 RF dsRNA in the presence of AfSV1. Taken together, our results show the unique infectious entity of AfSV2 and the expansion of yadokarivirus partners in the family Pseudototiviridae and provide interesting evolutionary insights.IMPORTANCEThe viral phylum Pisuviricota accommodates members with both double-stranded RNA (dsRNA) and (+)RNA genomes. Some members of the second group display peculiar virus lifestyles. These include (+)RNA yadkariviruses, which are capsidless and highjack the capsid of their partner dsRNA viruses in the order Ghabrivirales of a different phylum Duplornaviricota. We identified the partner dsRNA virus (AfSV1, a victorivirus) of a yadokarivirus (AfSV2) from the ascomycete Aspergillus foetidus. AfSV2 is infectious in the presence of AfSV1 in three forms: purified particles, transforming full-length complementary DNA, and, surprisingly, the purified replicative form dsRNA. These combined results expand yadokarivirus partner viruses to the family Pseudototiviridae and provide evidence for AfSV2 as a unique infectious entity as well as interesting evolutionary insights.

DOI： 10.1128/jvi.02166-24

Evidence for the replication of a plant rhabdovirus in its arthropod mite vector. International journal

Hideki Kondo, Miki Fujita, Paul Telengech, Kazuyuki Maruyam, Kiwamu Hyodo, Aline Daniele Tassi, Ronald Ochoa, Ida Bagus Andika, Nobuhiro Suzuki

Virus research 351 199522 - 199522 2025.1

Language：English Publishing type：Research paper (scientific journal)

Transmission of plant viruses that replicate in the insect vector is known as persistent-propagative manner. However, it remains unclear whether such virus-vector relationships also occur between plant viruses and other biological vectors such as arthropod mites. In this study, we investigated the possible replication of orchid fleck virus (OFV), a segmented plant rhabdovirus, within its mite vector (Brevipalpus californicus s.l.) using quantitative RT-qPCR, western blotting and next-generation sequencing. Time-course RT-qPCR and western blot analyses showed an increasing OFV accumulation pattern in mites after virus acquisition. Since OFV genome expression requires the transcription of polyadenylated mRNAs, polyadenylated RNA fractions extracted from the viruliferous mite samples and OFV-infected plant leaves were used for RNA-seq analysis. In the mite and plant datasets, a large number of sequence reads were aligned to genomic regions of OFV RNA1 and RNA2 corresponding to transcribed viral gene mRNAs. This includes the short polyadenylated transcripts originating from the leader and trailer regions at the ends of the viral genome, which are believed to play a crucial role in viral transcription/replication. In contrast, a low number of reads were mapped to the non-transcribed regions (gene junctions). These results strongly suggested that OFV gene expression occurs both in mites and plants. Additionally, deep sequencing revealed the accumulation of OFV-derived small RNAs in mites, although their size profiles differ from those found in plants. Taken together, our results indicated that OFV replicates within a mite vector and is targeted by the RNA-silencing mechanism.

DOI： 10.1016/j.virusres.2024.199522

Changes to virus taxonomy and the ICTV Statutes ratified by the International Committee on Taxonomy of Viruses (2024) Reviewed

Peter Simmonds, Evelien M. Adriaenssens, Elliot J. Lefkowitz, Hanna M. Oksanen, Stuart G. Siddell, Francisco Murilo Zerbini, Poliane Alfenas-Zerbini, Frank O. Aylward, Donald M. Dempsey, Bas E. Dutilh, Juliana Freitas-Astúa, María Laura García, R. Curtis Hendrickson, Holly R. Hughes, Sandra Junglen, Mart Krupovic, Jens H. Kuhn, Amy J. Lambert, Małgorzata Łobocka, Arcady R. Mushegian, Judit Penzes, Alejandro Reyes Muñoz, David L. Robertson, Simon Roux, Luisa Rubino, Sead Sabanadzovic, Donald B. Smith, Nobuhiro Suzuki, Dann Turner, Koenraad Van Doorslaer, Anne-Mieke Vandamme, Arvind Varsani

Archives of Virology 169 ( 11 ) 2024.11

Language：English Publishing type：Research paper (scientific journal) Publisher：Springer Science and Business Media LLC

Abstract

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 2024. The entire ICTV membership was invited to vote on 203 taxonomic proposals that had been approved by the ICTV Executive Committee (EC) in July 2023 at the 55th EC meeting in Jena, Germany, or in the second EC vote in November 2023. All proposals were ratified by online vote. Taxonomic additions include one new phylum (Ambiviricota), one new class, nine new orders, three new suborders, 51 new families, 18 new subfamilies, 820 new genera, and 3547 new species (excluding taxa that have been abolished). Proposals to complete the process of species name replacement to the binomial (genus + species epithet) format were ratified. Currently, a total of 14,690 virus species have been established.

DOI： 10.1007/s00705-024-06143-y

Other Link： https://link.springer.com/article/10.1007/s00705-024-06143-y/fulltext.html

Virus Research: 40 years and still going strong Invited Reviewed

Ben Berkhout, Esteban Domingo, Nobuhiro Suzuki

Virus Research 350 199493 - 199493 2024.11

Ancient environmental microbiomes and the cryosphere Reviewed

Alexander D. Williams, Vivian W. Leung, Julian W. Tang, Nishimura Hidekazu, Nobuhiro Suzuki, Andrew C. Clarke, David A. Pearce, Tommy Tsan-Yuk Lam

Trends in Microbiology 2024.10

New lineages of RNA viruses from clinical isolates of Rhizopus microsporus revealed by fragmented and primer-ligated dsRNA sequencing (FLDS) analysis. Reviewed International journal

Wasiatus Sa'diyah, Yan-Jie Zhao, Yuto Chiba, Hideki Kondo, Nobuhiro Suzuki, Sayaka Ban, Takashi Yaguchi, Syun-Ichi Urayama, Daisuke Hagiwara

mSphere 9 e0034524 2024.7

Language：English Publishing type：Research paper (scientific journal)

Rhizopus microsporus is a species in the order Mucorales that is known to cause mucormycosis, but it is poorly understood as a host of viruses. Here, we examined 25 clinical strains of R. microsporus for viral infection with a conventional double-stranded RNA (dsRNA) assay using agarose gel electrophoresis (AGE) and the recently established fragmented and primer-ligated dsRNA sequencing (FLDS) protocol. By AGE, five virus-infected strains were detected. Then, full-length genomic sequences of 12 novel RNA viruses were revealed by FLDS, which were related to the families Mitoviridae, Narnaviridae, and Endornaviridae, ill-defined groups of single-stranded RNA (ssRNA) viruses with similarity to the established families Virgaviridae and Phasmaviridae, and the proposed family "Ambiguiviridae." All the characterized viruses, except a potential phasmavirid with a negative-sense RNA genome, had positive-sense RNA genomes. One virus belonged to a previously established species within the family Mitoviridae, whereas the other 11 viruses represented new species or even new genera. These results show that the fungal pathogen R. microsporus harbors diverse RNA viruses and extend our understanding of the diversity of RNA viruses in the fungal order Mucorales, division Mucoromycota. Identifying RNA viruses from clinical isolates of R. microsporus may expand the repertoire of natural therapeutic agents for mucormycosis in the future.IMPORTANCEThe diversity of mycoviruses in fungal hosts in the division Mucoromycota has been underestimated, mainly within the species Rhizopus microsporus. Only five positive-sense RNA genomes had previously been discovered in this species. Because current sequencing methods poorly complete the termini of genomes, we used fragmented and primer-ligated double-stranded RNA sequencing to acquire the full-length genomes. Eleven novel mycoviruses were detected in this study, including the first negative-sense RNA genome reported in R. microsporus. Our findings extend the understanding of the viral diversity in clinical strains of Mucoromycota, may provide insights into the pathogenesis and ecology of this fungus, and may offer therapeutic options.

DOI： 10.1128/msphere.00345-24

　 PREV - NEXT 　

1
2
3
4
5
6
7
8
9
10