Characterisation of DNA forms associated with cassava latent virus infection

Stanley, John; Townsend, R.

doi:10.1093/nar/13.7.2189

Cited by 100 publications

(81 citation statements)

References 23 publications

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“…6, inset); they were probably dimers. Similar dimer molecules have been described with A C M V D N A (Stanley & Townsend, 1985). No defective molecules (minicircles) were observed.…”

Section: Short Communication (A) (B) (C) (A) (B) (C) (D) (E)supporting

confidence: 85%

A Geminivirus, Serologically Related to Maize Streak Virus, from Digitaria sanguinalis from Vanuatu

Dollet¹,

Accotto

Vaccari

et al. 1986

Journal of General Virology

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SUMMARYElectron microscopy of purified particles of a virus found in Dig#aria sanguinalis from Vanuatu (formerly New Hebrides) indicated that it is a geminivirus. Preparations of virus particles contained one coat protein of tool. wt. about 27 500 and circular and linear single-stranded DNA about 2350 nucleotides in length. In thin sections of infected cells, geminate particles were found in crystalline arrays both in nuclei and in the cytoplasm. The virus is serologically related to maize streak virus but differs from it with a serological differentiation index of 3.A striate mosaic disease of Digitaria sanguinatis in Vanuatu (formerly New Hebrides) was described some years ago (Dollet & De Taffin, 1979), but the causal agent was not identified. In this paper, we show that the diseased plants contain geminate virus particles (Francki et al., 1985; Harrison, 1985) that are serologically related to maize streak virus (MSV) (Bock et al., 1974).Infected D. sanguinalis plants were collected in the field and vegetatively propagated in an insect-proof glasshouse. Healthy D. sanguinalis was grown from seed in sterilized soil in the same glasshouse.Pieces of diseased leaf were fixed in glutaraldehyde and osmium tetroxide and embedded in epoxy resin (Dollet et al., 1983). Sections were stained in uranyl acetate and lead citrate. Linear aggregates of geminate particles (16 to 21 nm) were observed in the nuclei of companion and phloem parenchyma cells, often in large amounts (Fig. 1). Similar arrays of particles were also found in intact areas of cytoplasm, in cells in which nuclei appeared to be intact. Among other geminiviruses, this unusual location has been reported only for chloris striate mosaic virus (CSMV) (Francki et al., 1979). Virus particles were purified by a method derived from that of Larsen & Duffus (1984). Frozen leaves were ground in 0-1 M-potassium phosphate buffer pH 7, containing 10 mM-EDTA, 10 mM-sodium diethyldithiocarbamate and 20 mM-Na2SO3. The sap was treated with 1% Triton X-100 and clarified with 1/10 vol. chloroform/butanol (1:1, v/v). Virus particles were concentrated with 12% polyethylene glycol and 0.2 M-NaC1 and a cycle of differential centrifugation. The pellets were dissolved in 0.1 M-phosphate buffer pH 7 containing 10 mM-EDTA, and the virus preparation ultracentrifuged in a 10 to 40% sucrose density gradient prepared in the same buffer. The virus-containing band was concentrated by ultracentrifugation, and the sucrose density gradient centrifugation was then repeated. The yield was about 6 mg of virus per kg of fresh leaf tissue (a relatively large amount for a geminivirus), estimated assuming that Almg/ml is 7"7 (Goodman & Bird, 1978). Most particles in the purified virus ~ ~260nm, I cm preparations were geminate (Fig. 2), and the remaining few were single. The methods of 0000-6920 © 1986 SGM

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“…6, inset); they were probably dimers. Similar dimer molecules have been described with A C M V D N A (Stanley & Townsend, 1985). No defective molecules (minicircles) were observed.…”

Section: Short Communication (A) (B) (C) (A) (B) (C) (D) (E)supporting

confidence: 85%

A Geminivirus, Serologically Related to Maize Streak Virus, from Digitaria sanguinalis from Vanuatu

Dollet¹,

Accotto

Vaccari

et al. 1986

Journal of General Virology

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“…2, lane 7) is also seen in wild-type infections (Fig. 2, lane 8), and is thought to be a multimeric form of MSV DNA; dimeric forms of ACMV have been reported by Stanley & Townsend (1985). The molecule does not hybridize to a probe specific for pBIN19.…”

Section: Infectivity Of Mutant Msv Clonesmentioning

confidence: 82%

Mutational Analysis of the Virion-sense Genes of Maize Streak Virus

Boulton

Steinkellner

Donson

et al. 1989

Journal of General Virology

117

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SUMMARYInsertion and deletion mutagenesis of the two virion-sense genes, V1 and V2, of maize streak virus (MSV) prevents symptomatic infections following Agrobacteriummediated 'agroinoculation' of maize seedlings. These genes code for an Mr 10900 protein and for coat protein, respectively. Mutants containing insertions or deletions in the coat protein gene, V2, were able to replicate to low levels, producing dsDNA although virion ssDNA was not detected and symptoms were not observed. Hence, unlike the bipartite geminiviruses, MSV requires coat protein to produce symptomatic systemic infection. Mutations in gene V1 which considerably shortened the Mr 10900 protein (V1 gen¢) resulted either in low levels of replication, in which all the DNA forms associated with a wild-type infection were produced, or in no infection, in which case coat protein production may also have been affected. A V1 mutant generated in vivo with 11 of the 14 N-terminal amino acids altered, was viable and produced symptoms typical of a wild-type infection. Infectivity, assessed by replication and symptom expression, was restored by co-inoculating constructs containing single mutations in different open reading frames, thus rescue can occur by transcomplementation of gene products. The experiments showed that the mutations did not affect the nucleotide sequence requirements for replication and that in all cases intermolecular recombination eventually resulted in dominant wild-type virus.

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“…S5). The short direct repeat sequences flanking LIR and SIR may represent signal nucleotides for deletion (24).…”

Section: Resultsmentioning

confidence: 99%

A geminivirus-related DNA mycovirus that confers hypovirulence to a plant pathogenic fungus

Fù

et al. 2010

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

483

341

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Mycoviruses are viruses that infect fungi and have the potential to control fungal diseases of crops when associated with hypovirulence. Typically, mycoviruses have double-stranded (ds) or singlestranded (ss) RNA genomes. No mycoviruses with DNA genomes have previously been reported. Here, we describe a hypovirulenceassociated circular ssDNA mycovirus from the plant pathogenic fungus Sclerotinia sclerotiorum. The genome of this ssDNA virus, named Sclerotinia sclerotiorum hypovirulence-associated DNA virus 1 (SsHADV-1), is 2166 nt, coding for a replication initiation protein (Rep) and a coat protein (CP). Although phylogenetic analysis of Rep showed that SsHADV-1 is related to geminiviruses, it is notably distinct from geminiviruses both in genome organization and particle morphology. Polyethylene glycol-mediated transfection of fungal protoplasts was successful with either purified SsHADV-1 particles or viral DNA isolated directly from infected mycelium. The discovery of an ssDNA mycovirus enhances the potential of exploring fungal viruses as valuable tools for molecular manipulation of fungi and for plant disease control and expands our knowledge of global virus ecology and evolution.

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Characterisation of DNA forms associated with cassava latent virus infection

Cited by 100 publications

References 23 publications

A Geminivirus, Serologically Related to Maize Streak Virus, from Digitaria sanguinalis from Vanuatu

A Geminivirus, Serologically Related to Maize Streak Virus, from Digitaria sanguinalis from Vanuatu

Mutational Analysis of the Virion-sense Genes of Maize Streak Virus

A geminivirus-related DNA mycovirus that confers hypovirulence to a plant pathogenic fungus

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