Molecular Genetics of the Viruses Infecting the Plant Pathogenic Fungus Helminthosporium Victoriae

Ghabrial, Said A.; Havens, Wendy M.; Soldevila, Ana I.

doi:10.1201/9781420039122.ch9

Cited by 21 publications

(26 citation statements)

References 38 publications

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“…Satellite RNAs, which are generally significantly smaller in size than the genomic RNAs of the helper virus, are known to share very little or no sequence similarity with their helper viruses (Mayo et al, 2000;Bruening, 2002). PcV dsRNAs 3 and 4 (as well as those of the chrysovirus Hv145SV; Ghabrial et al, 2002;A. Soldevila and S. A. Ghabrial, unpublished) are of comparable size to dsRNAs 1 and 2 and all four dsRNAs share extended regions (50-75 nt) of high sequence similarity (>80 %) at both of their termini.…”

Section: Discussionmentioning

confidence: 96%

Molecular characterization of Penicillium chrysogenum virus: reconsideration of the taxonomy of the genus Chrysovirus

Jiāng

Ghabrial

2004

Journal of General Virology

112

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Molecular cloning and complete nucleotide sequencing of Penicillium chrysogenum virus (PcV) dsRNAs indicated that PcV virions contained four dsRNA segments with sizes of 3562, 3200, 2976 and 2902 bp. Each dsRNA segment had unique sequences and contained a single large open reading frame (ORF). In vitro translation of transcripts derived from full-length cDNA clones of PcV dsRNAs yielded single products of sizes similar to those predicted from the deduced amino acid sequences of the individual ORFs. Sequence similarity searches revealed that dsRNA1 encodes a putative RNA-dependent RNA polymerase. In this study, it was determined that dsRNA2 encodes the major capsid protein and that p4, encoded by dsRNA4, is virion-associated as a minor component. All four dsRNAs of PcV, like the genomic segments of viruses with multipartite genomes, were found to have extended regions of highly conserved terminal sequences at both ends. In addition to the strictly conserved 5′-terminal 10 nt, a second region consisting of reiteration of the sequence CAA was found immediately upstream of the AUG initiator codon. These (CAA) n repeats are reminiscent of the translational enhancer elements of tobamoviruses. The 3′-terminal 14 nt were also strictly conserved. As PcV and related viruses with four dsRNA segments (genus Chrysovirus) have not been previously characterized at the molecular level, they were provisionally classified in the family Partitiviridae, comprising viruses with bipartite genomes. This study represents the first report on molecular characterization of a chrysovirus and the results suggest the creation of a new family of mycoviruses with multipartite dsRNA genomes to accommodate PcV and related viruses.

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Section: Discussionmentioning

confidence: 96%

Molecular characterization of Penicillium chrysogenum virus: reconsideration of the taxonomy of the genus Chrysovirus

Jiāng

Ghabrial

2004

Journal of General Virology

112

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“…Such infections have been termed latent, even though the virus may replicate to high titers (Buck, 1986). Several mycoviruses can induce hypovirulence in plant pathogenic fungi and have been extensively studied as they have the potential to identify unique physiological pathways that affect virulence in fungal plant pathogens, and as biological control agents in plant disease management (Dawe and Nuss, 2001;Buck and Brasier, 2002;Ghabrial et al, 2002;Tavantzis et al, 2002;Nuss 2005).…”

Section: Discussionmentioning

confidence: 98%

“…Hypovirulence in plant pathogenic fungi can be caused by several infectious cytoplasmic factors, including viruses, virus-like agents, and plamids (Elliston, 1982), but most commonly, hypovirulence has been associated with double-stranded RNA (dsRNA) genetic elements. The hypovirulence-associated mycoviruses in several plant pathogenic fungi have been characterized and classified into five virus families, the Chrysoviridae, Hypoviridae, Narnaviridae, Reoviridae, and Totiviridae, based on genome structure, particle morphology, or absence of an encoded coat protein (Buck, 1998;Hillman et al, 2000;Wickner et al, 2000;Ghabrial, 2002;Nuss, 2005).…”

Section: Introductionmentioning

confidence: 98%

Attenuation of Virulence in Sclerotinia homoeocarpa during Storage is Associated with Latent Infection by Ophiostoma mitovirus 3a

Deng

Boland

2006

Eur J Plant Pathol

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The hypovirulence-associated mitovirus, Ophiostoma mitovirus 3a (OMV3a), has been shown to be widespread in eastern Canadian populations of Sclerotinia homoeocarpa in the form of latent infection. Latent infection by OMV3a was not associated with an apparent phenotype and did not significantly reduce the growth and virulence of the pathogen. In the present study, we found that isolates of S. homoeocarpa latently infected by OMV3a can change to hypovirulent isolates after storage at 4°C, and that this attenuation of virulence was associated with increased concentration of the OMV3a virus. Recurrent observations revealed that up to 29.8% of latently infected isolates changed to hypovirulent isolates after 21 months of storage. Transmission of OMV3a dsRNA from latently infected isolates to virus-free isolates resulted in latent infection of the recipient isolates, indicating that latent infection by OMV3a was not associated with genetic differences in the fungal host. The RNA genomes of the OMV3a virus in an isogenic pair of latently infected and hypovirulent isolates were sequenced and compared. Each of the two RNAs contained an open reading frame of 726 amino acids with conserved motifs typical of RNA-dependent RNA polymerase (RdRp). The OMV3a RNA sequences in these two isolates share 95.1% nucleotide and 94.6% amino acid sequence identities. The development of hypovirulence from latent infection by OMV3a virus may provide new strategies to improve the biological control efficacy of hypovirulence in dollar spot management.

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“…Phylogenetically, DsRV1 grouped most closely to a dsRNA element isolated from Phlebiopsis gigantea ( P g V 2 ) . I t s n e x t c l o s e s t r e l a t i v e s a r e v i r u s e s belonging to the Chrysoviridae (Hv145sV and PcV) [18,25].…”

Section: Discussionmentioning

confidence: 99%

“…The closest relatives to DsRV1 and PgV2 are another dsRNA element from P. gigantea (PgV1) and viruses belonging to the Chrysoviridae (Hv145SV and PcV) [18,25]. The Chrysoviridae represents a family newly erected to accommodate mycoviruses with multipartite dsRNA genomes of three to four segments [19], previously considered to be part of the genus Chrysovirus in the Partitiviridae [25].…”

Section: Viruses In the Genusmentioning

confidence: 99%

Characterization of a novel dsRNA element in the pine endophytic fungus Diplodia scrobiculata

et al. 2011

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Molecular Genetics of the Viruses Infecting the Plant Pathogenic Fungus Helminthosporium Victoriae

Cited by 21 publications

References 38 publications

Molecular characterization of Penicillium chrysogenum virus: reconsideration of the taxonomy of the genus Chrysovirus

Molecular characterization of Penicillium chrysogenum virus: reconsideration of the taxonomy of the genus Chrysovirus

Attenuation of Virulence in Sclerotinia homoeocarpa during Storage is Associated with Latent Infection by Ophiostoma mitovirus 3a

Characterization of a novel dsRNA element in the pine endophytic fungus Diplodia scrobiculata

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