Novel Victorivirus from a Pakistani Isolate of Alternaria alternata Lacking a Typical Translational Stop/Restart Sequence Signature

Jamal, Atif; Sato, Yukiyo; Shahi, Sabitree; Shamsi, Wajeeha; Kondō, Hideki; Suzuki, Nobuhiro

doi:10.3390/v11060577

Cited by 34 publications

(30 citation statements)

References 68 publications

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“…The third element of the -1 frameshifting mechanism is a short spacer region between the slippery site and the pseudoknot, and is a 19 nt long stretch in TkTV1/Mg10. It was recently demonstrated that the presence of -1 ribosomal frameshifting elements does not necessarily lead to the expression of a fusion protein (Jamal et al, 2019). Although the expression of a CP-RdRp fusion protein by TkTV1 is yet to be confirmed experimentally, the presence of the -1 frameshifting signature in TkTV1 genome might induce the expression of an ORF1-ORF2 (CP-RdRp) fusion protein of 1518 aa with a molecular weight of 172.020 kDa.…”

Section: Resultsmentioning

confidence: 99%

A Novel Totivirus Naturally Occurring in Two Different Fungal Genera

Khalifa

MacDiarmid

2019

Front. Microbiol.

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Mycoviruses are widely distributed across different phyla of the fungal kingdom. Viruses that share significant sequence similarities have been reported in different fungi, suggesting descent from a common ancestor. In this study, two fungal genera isolated from the same sample, Trichoderma koningiopsis isolate Mg10 and Clonostachys rosea isolate Mg06, were reported to have identical double-stranded RNA (dsRNA) profiles that consist of two virus-like, dsRNA elements (dsRNA-L and dsRNA-S). The complete sequence and genome organization of dsRNA-L from isolate Mg10 was determined. It is 4712 nucleotides (nt) long and contains two non-overlapping open reading frames (ORFs) that code for proteins with similarities to totiviruses. Consequently the virus was given the proposed name Trichoderma koningiopsis totivirus 1 (TkTV1/Mg10). The TkTV1/Mg10 genome structure resembles that of yeast totiviruses in which the region preceding the stop codon of ORF1 contains the elements required for -1 ribosomal frameshifting which may induce the expression of an ORF1–ORF2 (CP-RdRp) fusion protein. Sequence analyses of viral dsRNA-L from C. rosea isolate Mg06 revealed that it is nearly identical with that of TkTV1/Mg10. This relatedness was confirmed by northern blot hybridization and indicates very recent natural horizontal transmission of this virus between unrelated fungi. TkTV1 purified isometric virions were ∼38–40 nm in diameter and were able to transfect T. koningiopsis and C. rosea protoplasts. This is another report of a mycovirus present naturally in two taxonomically distinct fungi.

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Section: Resultsmentioning

confidence: 99%

A Novel Totivirus Naturally Occurring in Two Different Fungal Genera

Khalifa

MacDiarmid

2019

Front. Microbiol.

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“…The complete genome sequence of PjPmV1 was determined by next-generation sequencing (NGS) and Sanger sequencing. We performed NGS (HiSeq 2500, Illumina, Inc.) as previously described (Jamal et al, 2019;Shamsi et al, 2019). For NGS, we submitted a mixed dsRNA preparation (called "pool A1") from three fungal strains including P. janthinellum strain A58 and Alternaria alternata strain A16 (Jamal et al, 2019).…”

Section: Extraction Sequencing and Northern Hybridization Of Dsrnamentioning

confidence: 99%

“…We performed NGS (HiSeq 2500, Illumina, Inc.) as previously described (Jamal et al, 2019;Shamsi et al, 2019). For NGS, we submitted a mixed dsRNA preparation (called "pool A1") from three fungal strains including P. janthinellum strain A58 and Alternaria alternata strain A16 (Jamal et al, 2019). The 5'-and 3'-terminal nucleotide sequences were determined by 3' RNA ligase-mediated rapid amplification of cDNA ends (3' RLM-RACE) using dsRNA as templates with the method of Lin et al (2013).…”

Section: Extraction Sequencing and Northern Hybridization Of Dsrnamentioning

confidence: 99%

“…A novel five-segmented polymycovirus, named Penicillium janthinellum polymycovirus 1 (PjPmV1), was discovered from one of fungal strains collected in Pakistan as previously described (Jamal et al, 2019;Shamsi et al, 2019;Sato et al, 2020). The host fungal strain A58 was identified as Penicillium species P. janthinellum based on the ITS sequence (see Materials and Methods).…”

Section: Molecular Characterization Of Pjpmv1mentioning

confidence: 99%

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Molecular Characterization of a Novel Polymycovirus From Penicillium janthinellum With a Focus on Its Genome-Associated PASrp

et al. 2020

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The genus Polymycovirus of the family Polymycoviridae accommodates fungal RNA viruses with different genomic segment numbers (four, five, or eight). It is suggested that four members form no true capsids and one forms filamentous virus particles enclosing double-stranded RNA (dsRNA). In both cases, viral dsRNA is associated with a viral protein termed "proline-alanine-serine-rich protein" (PASrp). These forms are assumed to be the infectious entity. However, the detailed molecular characteristics of PASrps remain unclear. Here, we identified a novel five-segmented polymycovirus, Penicillium janthinellum polymycovirus 1 (PjPmV1), and characterized its purified fraction form in detail. The PjPmV1 had five dsRNA segments associated with PASrp. Density gradient ultracentrifugation of the PASrp-associated PjPmV1 dsRNA revealed its uneven structure and a broad fractionation profile distinct from that of typical encapsidated viruses. Moreover, PjPmV1-PASrp interacted in vitro with various nucleic acids in a sequence-non-specific manner. These PjPmV1 features are discussed in view of the diversification of genomic segment numbers of the genus Polymycovirus.

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“…Almost all victoriviruses infect their natural hosts without any apparent symptoms; examples include Rosellinia necatrix victorivirus 1 and Alternaria alternata victorivirus 1 (Chiba et al, 2013a;Jamal et al, 2019). Exceptions include Helminthosporium victoriae virus 190S, which induces disease symptoms in its natural host H. victoriae (Xie et al, 2016).…”

Section: Discussionmentioning

confidence: 99%

Population Structure of Double-Stranded RNA Mycoviruses That Infect the Rice Blast Fungus Magnaporthe oryzae in Japan

et al. 2020

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Various viruses infect Magnaporthe oryzae (syn. Pyricularia oryzae), which is a well-studied fungus that causes rice blast disease. Most research has focused on the discovery of new viruses and the hypovirulence-associated traits conferred by them. Therefore, the diversity and prevalence of viruses in wild fungal populations have not been explored. We conducted a comprehensive screening of M. oryzae mycoviruses from various regions in Japan using double-stranded RNA (dsRNA) electrophoresis and RT-PCR assays. We detected three mycoviruses, Magnaporthe oryzae virus 2 (MoV2), Magnaporthe oryzae chrysovirus 1 (MoCV1), and Magnaporthe oryzae partitivirus 1 (MoPV1), among 127 of the 194 M. oryzae strains screened. The most prevalent virus was MoPV1 (58.8%), which often co-infected in a single fungal strain together with MoV2 or MoCV1. MoV2 and MoCV1 were found in 22.7 and 10.8% of strains, respectively, and they were usually distributed in different regions so that mixed-infection with these two mycoviruses was extremely rare. The predominance of MoPV1 in M. oryzae is supported by significant negative values from neutrality tests, which indicate that the population size of MoPV1 tends to increase. Population genetic analyses revealed high nucleotide diversity and the presence of phylogenetically diverse subpopulations among the MoV2 isolates. This was not the case for MoPV1. Furthermore, studies of a virus-cured M. oryzae strain revealed that MoV2 does not cause any abnormalities or symptoms in its host. However, a leaf sheath inoculation assay showed that its presence slightly increased the speed of mycelial growth, compared with virus-free mycelia. These results demonstrate that M. oryzae in Japan harbors diverse dsRNA mycovirus communities with wide variations in their population structures among different viruses.

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Novel Victorivirus from a Pakistani Isolate of Alternaria alternata Lacking a Typical Translational Stop/Restart Sequence Signature

Cited by 34 publications

References 68 publications

A Novel Totivirus Naturally Occurring in Two Different Fungal Genera

A Novel Totivirus Naturally Occurring in Two Different Fungal Genera

Molecular Characterization of a Novel Polymycovirus From Penicillium janthinellum With a Focus on Its Genome-Associated PASrp

Population Structure of Double-Stranded RNA Mycoviruses That Infect the Rice Blast Fungus Magnaporthe oryzae in Japan

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