Cryspovirus: a new genus of protozoan viruses in the family Partitiviridae

Nibert, Max L.; Woods, Keith M.; Upton, Steve J.; Ghabrial, Said A.

doi:10.1007/s00705-009-0513-7

Cited by 65 publications

(50 citation statements)

References 38 publications

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“…Our studies also raise the possibility of treating other diseases caused by protozoans bearing dsRNA viruses, which show endogenous virus-dependent pathogenicity, including Totiviridae present within Trichomonas vaginalis (Trichomonasvirus), Giardia lamblia (Giardiavirus), or Eimeria (Eimeravirus) (34,57), and Partitiviridae within Cryptosporidium parvum (Cryspovirus) (58,59). Potentially, agents targeting these putative pathogenicity factor viruses could prove similarly valuable for laboratory studies of these viruses as well.…”

Section: Antiviral Cures and The Generation Of Isogenic Lrv1mentioning

confidence: 94%

Antiviral screening identifies adenosine analogs targeting the endogenous dsRNALeishmaniaRNA virus 1 (LRV1) pathogenicity factor

Kuhlmann

Robinson

Bluemling

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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The endogenous double-stranded RNA (dsRNA) virus Leishmaniavirus (LRV1) has been implicated as a pathogenicity factor for leishmaniasis in rodent models and human disease, and associated with drug-treatment failures in Leishmania braziliensis and Leishmania guyanensis infections. Thus, methods targeting LRV1 could have therapeutic benefit. Here we screened a panel of antivirals for parasite and LRV1 inhibition, focusing on nucleoside analogs to capitalize on the highly active salvage pathways of Leishmania, which are purine auxotrophs. Applying a capsid flow cytometry assay, we identified two 2′-C-methyladenosine analogs showing selective inhibition of LRV1. Treatment resulted in loss of LRV1 with first-order kinetics, as expected for random virus segregation, and elimination within six cell doublings, consistent with a measured LRV1 copy number of about 15. Viral loss was specific to antiviral nucleoside treatment and not induced by growth inhibitors, in contrast to fungal dsRNA viruses. Comparisons of drug-treated LRV1 + and LRV1 − lines recapitulated LRV1-dependent pathology and parasite replication in mouse infections, and cytokine secretion in macrophage infections. Agents targeting Totiviridae have not been described previously, nor are there many examples of inhibitors acting against dsRNA viruses more generally. The compounds identified here provide a key proof-ofprinciple in support of further studies identifying efficacious antivirals for use in in vivo studies of LRV1-mediated virulence.trypanosomatid protozoan parasite | endobiont virus | viral segregation | chemotherapy | virulence

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Section: Antiviral Cures and The Generation Of Isogenic Lrv1mentioning

confidence: 94%

Antiviral screening identifies adenosine analogs targeting the endogenous dsRNALeishmaniaRNA virus 1 (LRV1) pathogenicity factor

Kuhlmann

Robinson

Bluemling

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…Members of family Partitiviridae are characterized by having genomes comprised of two linear, monocistronic dsRNA segments (1.4 to 2.4 kbp in length) (15,16). Most partitiviruses examined to date are typically associated with latent infections of their fungal, plant, and protozoan hosts (16).…”

mentioning

confidence: 99%

A Novel Partitivirus That Confers Hypovirulence on Plant Pathogenic Fungi

Xiao

Chéng

Tang

et al. 2014

J Virol

Self Cite

131

103

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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. Hypovirulence and associated traits of strain WF-1 and SsPV1/WF-1 were readily cotransmitted horizontally via hyphal contact to different vegetative compatibility groups of S. sclerotiorum and interspecifically to Sclerotinia nivalis and Sclerotinia minor. S. sclerotiorum strain 1980 transfected with purified SsPV1/WF-1 virions also exhibited hypovirulence and associated traits similar to those of strain WF-1. Moreover, introduction of purified SsPV1/WF-1 virions into strain KY-1 of Botrytis cinerea also resulted in reductions in virulence and mycelial growth and, unexpectedly, enhanced conidial production. However, virus infection suppressed hyphal growth of most germinating conidia of B. cinerea and was eventually lethal to infected hyphae, since very few new colonies could develop following germ tube formation. Taken together, our results support the conclusion that SsPV1/WF-1 causes hypovirulence in Sclerotinia spp. and B. cinerea. Cryo-EM (cryo-electron microscopy) reconstruction of the SsPV1 particle shows that it has a distinct structure with similarity to the closely related partitiviruses Fusarium poae virus 1 and Penicillium stoloniferum virus F. These findings provide new insights into partitivirus biological activities and clues about molecular interactions between partitiviruses and their hosts. IMPORTANCEMembers of the Partitiviridae are believed to occur commonly in their phytopathogenic fungal and plant hosts. However, most partitiviruses examined so far appear to be associated with latent infections. Here we report a partitivirus, SsPV1/WF-1, that was isolated from a hypovirulent strain of Sclerotinia sclerotiorum and describe its biological and molecular features. We have demonstrated that SsPV1 confers hypovirulence. Furthermore, SsPV1 can infect and cause hypovirulence in Botrytis cinerea. Our study also suggests that SsPV1 has a vigorous ability to proliferate and spread via hyphal contact. SsPV1 can overcome vegetative incompatibility barriers and can be transmitted horizontally among different vegetative compatibility groups of S. sclerotiorum, even interspecifically. Cryo-EM reconstruction of SsPV1 shows that it has a distinct structure with similarity to closely related partitiviruses. Our studies exploit a novel system, SsPV1 and its hosts, which can provide the means to explore the mechanisms by which partitiviruses interact with their hosts.

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“…Brogiotto nero, two small-sized dsRNA bands (less than 2 kbp) were observed which, as reported in this paper, were sequenced and found to belong to a novel cryptic virus, for which the provisional name of Cryptic viruses are members of the family Partitiviridae, which comprises isometric viruses infecting monocotyledonous and dicotyledonous plant species, currently classified in the genera Alphacryptovirus and Betacryptovirus [4]. This family also embraces the genera Partitivirus and Cryspovirus which include fungal and protozoan dsRNA viruses, respectively [4,5]. Plant-infecting members of the family Partitiviridae are transmitted through seeds and pollen but not by grafting or mechanical inoculation, and occur in very low concentration in the host plant [4], and apparently have no economic impact.…”

Section: Introductionmentioning

confidence: 93%

The complete nucleotide sequence and genome organization of Fig cryptic virus, a novel bipartite dsRNA virus infecting fig, widely distributed in the Mediterranean basin

et al. 2011

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Two double-stranded RNA (dsRNA) segments of a virus with a bipartite genome identified in fig (Ficus carica L.) and denoted Fig cryptic virus (FCV) were cloned and sequenced. Viral dsRNAs are 1696 bp (RNA-1) and 1415 bp (RNA-2) in size. RNA-1 contains a single ORF (1419 nt) potentially encoding a 54 kDa protein and comprising the conserved amino acid motifs of the RNA-dependent RNA polymerase (RdRp) domain of species of the genus Alphacryptovirus. Its full-length amino acid sequence has the highest identity with Raphanus sativus cryptic virus 2 (RsCV-2) (36%), Beet cryptic virus 3 (BCV-3) (36%) and Fragaria chiloensis cryptic virus (FCCV) (34%). RNA-2 has also a single ORF (1014 nt) coding for a polypeptide with a predicted molecular mass of 38 kDa, identified as the viral coat protein (CP). In a phylogenetic tree constructed with the amino acid sequences of the RdRp domain, FCV clusters in a clade comprising BCV-3 and a number of tentative species of the genus Alphacryptovirus. FCV is not mechanically transmissible. It was detected in fig orchards of six Mediterranean countries (Albania, Algeria, Italy, Lebanon, Syria and Tunisia) where it does not seem to induce a visible disease.

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Cryspovirus: a new genus of protozoan viruses in the family Partitiviridae

Cited by 65 publications

References 38 publications

Antiviral screening identifies adenosine analogs targeting the endogenous dsRNALeishmaniaRNA virus 1 (LRV1) pathogenicity factor

Antiviral screening identifies adenosine analogs targeting the endogenous dsRNALeishmaniaRNA virus 1 (LRV1) pathogenicity factor

A Novel Partitivirus That Confers Hypovirulence on Plant Pathogenic Fungi

The complete nucleotide sequence and genome organization of Fig cryptic virus, a novel bipartite dsRNA virus infecting fig, widely distributed in the Mediterranean basin

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