Synthesis of full-length transcripts of beet western yellows virus RNA: Messenger properties and biological activity in protoplasts

Veidt, Isabelle; Bouzoubaa, S.; Leiser, Robert-Matthias; Ziegler-Graff, Véronique; Guilley, H.; Richards, K.; Jonard, G.

doi:10.1016/0042-6822(92)90073-x

Cited by 95 publications

(71 citation statements)

References 42 publications

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“…P0 is encoded by the 5Ј-proximal gene of BWYV RNA, and the protein is readily detected when viral RNA is translated in vitro (38). Therefore, we asked whether full-length BWYV RNA can elicit silencing suppression in the patch coinfiltration assay.…”

Section: Resultsmentioning

confidence: 99%

P0 of Beet Western Yellows Virus Is a Suppressor of Posttranscriptional Gene Silencing

Pfeffer

Dunoyer

Heim

et al. 2002

J Virol

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202

144

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Higher plants employ a homology-dependent RNA-degradation system known as posttranscriptional gene silencing (PTGS) as a defense against virus infection. Several plant viruses are known to encode proteins that can suppress PTGS. Here we show that P0 of beet western yellows virus (BWYV) displays strong silencing suppressor activity in a transient expression assay based upon its ability to inhibit PTGS of green fluorescent protein (GFP) when expressed in agro-infiltrated leaves of Nicotiana benthamiana containing a GFP transgene. PTGS suppressor activity was also observed for the P0s of two other poleroviruses, cucurbit aphid-borne yellows virus and potato leafroll virus. P0 is encoded by the 5-proximal gene in BWYV RNA but does not accumulate to detectable levels when expressed from the genome-length RNA during infection. The low accumulation of P0 and the resulting low PTGS suppressor activity are in part a consequence of the suboptimal translation initiation context of the P0 start codon in viral RNA, although other factors, probably related to the viral replication process, also play a role. A mutation to optimize the P0 translation initiation efficiency in BWYV RNA was not stable during virus multiplication in planta. Instead, the P0 initiation codon in the progeny was frequently replaced by a less efficient initiation codon such as ACG, GTG, or ATA, indicating that there is selection against overexpression of P0 from the viral genome.Most if not all plants possess a defense mechanism against virus infection known as posttranscriptional gene silencing (PTGS; see reference 44 for a recent review). PTGS is a homology-dependent RNA degradation system to recognize and degrade viral RNA (and any homologous transgene mRNA) in the cytoplasm. Mechanistically similar phenomena exist in animals and fungi (reviewed in references 4, 13, and 35). The mechanism by which a virus infection triggers PTGS in plants is not fully understood, but double-stranded RNA is a strong inducer of PTGS (43) and such a form is produced during replication of an RNA virus. Production of small RNAs of ϳ21 to 23 nucleotides, called small interfering RNAs (siRNAs), corresponding to both the plus and minus strands of the target RNA is associated with PTGS (12,13,45). In plants, gene silencing at one site can trigger PTGS in distant tissues and across a graft union (29, 39a). The mobile signal, which must consist at least in part of homologous RNA, is thought to move from cell to cell through plasmodesmata and systemically via the vasculature. Some plant viruses have been shown to encode proteins which can counteract PTGS (8,22,39,40,42). These silencing suppressor proteins may act at different steps in the PTGS pathway. Thus, (i) the potyvirus helper component-proteinase (HCPro) interferes with initiation and maintenance of silencing at a step coincident with or upstream of siRNA production (1,7,16,23,24), (ii) the 2b protein of cucumber mosaic virus (CMV) prevents initiation of PTGS in new growth by inhibiting the long-range PTGS signaling acti...

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Section: Resultsmentioning

confidence: 99%

P0 of Beet Western Yellows Virus Is a Suppressor of Posttranscriptional Gene Silencing

Pfeffer

Dunoyer

Heim

et al. 2002

J Virol

Self Cite

202

144

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“…LEAKY SCANNING In all luteoviruses, ORFs 3 and 4, and in subgroup II luteoviruses, ORFs 0 and 1 (65,106,119), are translated by leaky scanning.…”

Section: Translationmentioning

confidence: 99%

Barley Yellow Dwarf Viruses

Miller

Rasochova²

1997

Annu. Rev. Phytopathol.

215

154

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Barley yellow dwarf viruses represent one of the most economically important and ubiquitous groups of plant viruses. This review focuses primarily on four research areas in which progress has been most rapid. These include (a) evidence supporting reclassification of BYDVs into two genera; (b) elucidation of gene function and novel mechanisms controlling gene expression; (c) initial forays into understanding the complex interactions between BYDV virions and their aphid vectors; and (d ) replication of a BYDV satellite RNA. Economic losses, symptomatology, and means of control of BYD are also discussed.

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“…1 for a genetic map). The 3Ј-located genes are expressed from a subgenomic RNA (7,29,35). ORF3 encodes the major capsid protein of about 22 kDa.…”

Section: Beet Western Yellows Virus (Bwyv) Is a Member Of Thementioning

confidence: 99%

Effects of Point Mutations in the Readthrough Domain of the Beet Western Yellows Virus Minor Capsid Protein on Virus Accumulation In Planta and on Transmission by Aphids

Brault

Mutterer

Scheidecker

et al. 2000

J Virol

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Point mutations were introduced into or near five conserved sequence motifs of the readthrough domain of the beet western yellows virus minor capsid protein P74. The mutant virus was tested for its ability to accumulate efficiently in agroinfected plants and to be transmitted by its aphid vector, Myzus persicae. The stability of the mutants in the agroinfected and aphid-infected plants was followed by sequence analysis of the progeny virus. Only the mutation Y201D was found to strongly inhibit virus accumulation in planta following agroinfection, but high accumulation levels were restored by reversion or pseudoreversion at this site. Four of the five mutants were poorly aphid transmissible, but in three cases successful transmission was restored by pseudoreversion or second-site mutations. The same second-site mutations in the nonconserved motif PVT(32-34) were shown to compensate for two distinct primary mutations (R24A and E59A/D60A), one on each side of the PVT sequence. In the latter case, a second-site mutation in the PVT motif restored the ability of the virus to move from the hemocoel through the accessory salivary gland following microinjection of mutant virus into the aphid hemocoel but did not permit virus movement across the epithelium separating the intestine from the hemocoel. Successful movement of the mutant virus across both barriers was accompanied by conversion of A59 to E or T, indicating that distinct features of the readthrough domain in this region operate at different stages of the transmission process.

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Synthesis of full-length transcripts of beet western yellows virus RNA: Messenger properties and biological activity in protoplasts

Cited by 95 publications

References 42 publications

P0 of Beet Western Yellows Virus Is a Suppressor of Posttranscriptional Gene Silencing

P0 of Beet Western Yellows Virus Is a Suppressor of Posttranscriptional Gene Silencing

Barley Yellow Dwarf Viruses

Effects of Point Mutations in the Readthrough Domain of the Beet Western Yellows Virus Minor Capsid Protein on Virus Accumulation In Planta and on Transmission by Aphids

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