Molecular, Cellular, and Structural Biology of Grapevine fanleaf virus

Schmitt-Keichinger, Corinne; Hemmer, Caroline; Berthold, François; Ritzenthaler, Christophe

doi:10.1007/978-3-319-57706-7_4

Cited by 15 publications

(35 citation statements)

References 101 publications

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“…Plasmid pVecP2-2A:EG contains the cDNA of GFLV-RNA2 and the EGFP coding sequence inserted between the 2A HP and 2B MP coding sequences [31]. This plasmid codes for a suboptimal R/G cleavage site between the 2A HP and EGFP domains within the polyprotein P2 and allows the expression of a 2A:EGFP fusion protein in addition to free EGFP (see also Figure 2).…”

Section: Cloning Of 2c Cp Mutations Into Gflv-egfp Infectious Clonesmentioning

confidence: 99%

“…In order to visualize GFLV cell-to-cell movement in planta, we used an EGFP encoding cDNA infectious clone of GFLV-RNA2 [31] along with the infectious clone of GFLV-RNA1 [30] to generate the GFLV-EGFP inoculum ( Figure 2). A movement-deficient control was obtained by deleting the 2C CP coding sequence from the recombinant EGFP encoding infectious clone (∆CP-EGFP construct) ( Figure 2).…”

Section: A Gflv Encoding Egfp Allows Short Distance Movement Visualizmentioning

confidence: 99%

See 1 more Smart Citation

From a Movement-Deficient Grapevine Fanleaf Virus to the Identification of a New Viral Determinant of Nematode Transmission

Belval

Marmonier

Schmitt-Keichinger

et al. 2019

Viruses

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Grapevine fanleaf virus (GFLV) and arabis mosaic virus (ArMV) are nepoviruses responsible for grapevine degeneration. They are specifically transmitted from grapevine to grapevine by two distinct ectoparasitic dagger nematodes of the genus Xiphinema. GFLV and ArMV move from cell to cell as virions through tubules formed into plasmodesmata by the self-assembly of the viral movement protein. Five surface-exposed regions in the coat protein called R1 to R5, which differ between the two viruses, were previously defined and exchanged to test their involvement in virus transmission, leading to the identification of region R2 as a transmission determinant. Region R4 (amino acids 258 to 264) could not be tested in transmission due to its requirement for plant systemic infection. Here, we present a fine-tuning mutagenesis of the GFLV coat protein in and around region R4 that restored the virus movement and allowed its evaluation in transmission. We show that residues T258, M260, D261, and R301 play a crucial role in virus transmission, thus representing a new viral determinant of nematode transmission.Regions R3 (residues 207 to 210), R4 (residues 258 to 264), and R5 (residues 297 to 305) located in the jelly-roll domain B of the 2C CP protein were initially predicted to be exposed at the outer surface of the GFLV capsid from a GFLV 3D homology model derived from TRSV [27]. These regions differ between GFLV and ArMV and are described as motifs with possible function in encapsidation, movement, and transmission of GFLV. Following the obtention of the GFLV-F13 atomic structure at 3 Å resolution [21], we refined the structural features of these regions (Figure 1).Viruses 2019, 11, x FOR PEER REVIEW 6 of 23 Results Structural Environments of Regions R3, R4, and R5 of the GFLV 2C CPRegions R3 (residues 207 to 210), R4 (residues 258 to 264), and R5 (residues 297 to 305) located in the jelly-roll domain B of the 2C CP protein were initially predicted to be exposed at the outer surface of the GFLV capsid from a GFLV 3D homology model derived from TRSV [27]. These regions differ between GFLV and ArMV and are described as motifs with possible function in encapsidation, movement, and transmission of GFLV. Following the obtention of the GFLV-F13 atomic structure at 3 Å resolution [21], we refined the structural features of these regions (Figure 1).

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Section: Cloning Of 2c Cp Mutations Into Gflv-egfp Infectious Clonesmentioning

confidence: 99%

Section: A Gflv Encoding Egfp Allows Short Distance Movement Visualizmentioning

confidence: 99%

From a Movement-Deficient Grapevine Fanleaf Virus to the Identification of a New Viral Determinant of Nematode Transmission

Belval

Marmonier

Schmitt-Keichinger

et al. 2019

Viruses

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“…The absence of GFLV in the upper uninoculated leaves suggests that virus neutralization occurs early during infection, before systemic movement is initiated. To address more precisely the stage at which GFLV infection is arrested, we monitored infection using a recombinant GFLV encoding TagRFP (Schmitt-Keichinger et al, 2017). Whereas numerous infection foci (64.3 AE 5.9 foci) were counted on three inoculated leaves from three independent EG11-3 plants (Figure 7a and c), no evidence of infection in equivalent leaves from 23EG16-9 plants was detected ( Figure 7b and c).…”

Section: Virus Neutralization Occurs Early During Infection Before Cementioning

confidence: 99%

“…The latter is often considered to be the most detrimental and widespread grapevine viral disease as it affects vineyards worldwide, in particular those of high‐added value in which grapevine has been cultivated for centuries (Basso et al ., ). Fanleaf degenerative disease is characterized by a range of symptoms that include yellow mottling and distortion of the leaves that can resemble a fan, malformed canes with exceedingly short internodes, smaller than normal clusters and overall stunted vines of reduced vigour (Schmitt‐Keichinger et al ., ).…”

Section: Introductionmentioning

confidence: 97%

Nanobody‐mediated resistance to Grapevine fanleaf virus in plants

Hemmer

Djennane

Ackerer

et al. 2017

Plant Biotechnology Journal

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SummarySince their discovery, single‐domain antigen‐binding fragments of camelid‐derived heavy‐chain‐only antibodies, also known as nanobodies (Nbs), have proven to be of outstanding interest as therapeutics against human diseases and pathogens including viruses, but their use against phytopathogens remains limited. Many plant viruses including Grapevine fanleaf virus (GFLV), a nematode‐transmitted icosahedral virus and causal agent of fanleaf degenerative disease, have worldwide distribution and huge burden on crop yields representing billions of US dollars of losses annually, yet solutions to combat these viruses are often limited or inefficient. Here, we identified a Nb specific to GFLV that confers strong resistance to GFLV upon stable expression in the model plant Nicotiana benthamiana and also in grapevine rootstock, the natural host of the virus. We showed that resistance was effective against a broad range of GFLV isolates independently of the inoculation method including upon nematode transmission but not against its close relative, Arabis mosaic virus. We also demonstrated that virus neutralization occurs at an early step of the virus life cycle, prior to cell‐to‐cell movement. Our findings will not only be instrumental to confer resistance to GFLV in grapevine, but more generally they pave the way for the generation of novel antiviral strategies in plants based on Nbs.

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“…The GFLV genome consists of two single-stranded positive-sense RNA molecules (RNA-1 and RNA-2). The genomic RNAs are encapsidated in icosahedral particles of about 30 nm in diameter, assembled from 60 units of the capsid protein in a pseudo T=3 symmetry [17]. RNA-1 and RNA-2 are necessary for local and systemic infection in planta.…”

Section: Introductionmentioning

confidence: 99%

Detection of Multiple Variants of Grapevine Fanleaf Virus in Single Xiphinema index Nematodes

Garcia¹,

Hily

Komar³

et al. 2019

Viruses

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Grapevine fanleaf virus (GFLV) is responsible for a widespread disease in vineyards worldwide. Its genome is composed of two single-stranded positive-sense RNAs, which both show a high genetic diversity. The virus is transmitted from grapevine to grapevine by the ectoparasitic nematode Xiphinema index. Grapevines in diseased vineyards are often infected by multiple genetic variants of GFLV but no information is available on the molecular composition of virus variants retained in X. index following nematodes feeding on roots. In this work, aviruliferous X. index were fed on three naturally GFLV-infected grapevines for which the virome was characterized by RNAseq. Six RNA-1 and four RNA-2 molecules were assembled segregating into four and three distinct phylogenetic clades of RNA-1 and RNA-2, respectively. After 19 months of rearing, single and pools of 30 X. index tested positive for GFLV. Additionally, either pooled or single X. index carried multiple variants of the two GFLV genomic RNAs. However, the full viral genetic diversity found in the leaves of infected grapevines was not detected in viruliferous nematodes, indicating a genetic bottleneck. Our results provide new insights into the complexity of GFLV populations and the putative role of X. index as reservoirs of virus diversity.

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Molecular, Cellular, and Structural Biology of Grapevine fanleaf virus

Cited by 15 publications

References 101 publications

From a Movement-Deficient Grapevine Fanleaf Virus to the Identification of a New Viral Determinant of Nematode Transmission

From a Movement-Deficient Grapevine Fanleaf Virus to the Identification of a New Viral Determinant of Nematode Transmission

Nanobody‐mediated resistance to Grapevine fanleaf virus in plants

Detection of Multiple Variants of Grapevine Fanleaf Virus in Single Xiphinema index Nematodes

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