Mutations in Turnip mosaic virus genomes that have adapted to Raphanus sativus

The genetic basis for virulence in potyviruses is largely unknown. Earlier studies showed that there are two host types of Turnip mosaic virus (TuMV); the Brassica/Raphanus (BR)-host type infects both Brassica and Raphanus systemically, whereas the Brassica (B)-host type infects Brassica fully and systemically, but not Raphanus. The genetic basis of this difference has been explored by using the progeny of an infectious clone, p35Tunos; this clone is derived from the UK1 isolate, which is of the B-host type, but rarely infects Raphanus systemically and then only asymptomatically. Two inocula from one such infection were adapted to Raphanus by passaging, during which the infectivity and concentration of the virions of successive infections increased. The variant genomes in the samples, 16 in total, were sequenced fully. Four of the 39 nucleotide substitutions that were detected among the Raphanus sativus-adapted variant genomes were probably crucial for adaptation, as they were found in several variants with independent passage histories. These four were found in the protein 1 (P1), protein 3 (P3), cylindrical inclusion protein (CI) and genome-liked viral protein (VPg) genes. One of four ‘parallel evolution’ substitutions, 3430G→A, resulted in a 1100Met→Ile amino acid change in the C terminus of P3. It seems likely that this site is important in the initial stages of adaptation to R. sativus. Other independent substitutions were mostly found in the P3, CI and VPg genes.

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Comparison of two Turnip mosaic virus P1 proteins in their ability to co-localize with the Arabidopsis thaliana G3BP-2 protein

Virus Genes ◽

10.1007/s11262-021-01829-w ◽

2021 ◽

Vol 57 (2) ◽

pp. 233-237

Author(s):

Hendrik Reuper ◽

Björn Krenz

Keyword(s):

Arabidopsis Thaliana ◽

Mosaic Virus ◽

Specific Interaction ◽

Viral Proteins ◽

Turnip Mosaic Virus ◽

Stress Conditions ◽

C Terminus ◽

Positive Sense ◽

Key Factor ◽

Large Host

AbstractTurnip mosaic virus (TuMV), belonging to the genus Potyvirus (family Potyviridae), has a large host range and consists of a single-stranded positive sense RNA genome encoding 12 proteins, including the P1 protease. This protein which is separated from the polyprotein by cis cleavage at its respective C-terminus, has been attributed with different functions during potyviral infection of plants. P1 of Turnip mosaic virus (P1-TuMV) harbors an FGSF-motif and FGSL-motif at its N-terminus. This motif is predicted to be a binding site for the host Ras GTPase-activating protein-binding protein (G3BP), which is a key factor for stress granule (SG) formation in mammalian systems and often targeted by viruses to inhibit SG formation. We therefore hypothesized that P1-TuMV might interact with G3BP to control and regulate plant SGs to optimize cellular conditions for the production of viral proteins. Here, we analyzed the co-localization of the Arabidopsis thaliana G3BP-2 with the P1 of two TuMV isolates, namely UK 1 and DEU 2. Surprisingly, P1-TuMV-DEU 2 co-localized with AtG3BP-2 under abiotic stress conditions, whereas P1-TuMV-UK 1 did not. AtG3BP-2::RFP showed strong SGs formation after stress, while P1-UK 1::eGFP maintained a chloroplastic signal under stress conditions, the signal of P1-DEU 2::eGFP co-localized with that of AtG3BP-2::RFP. This indicates a specific interaction between P1-DEU 2 and the AtG3BP family which is not solely based on the canonical interaction motifs.

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Turnip mosaic virus determinants of virulence for Brassica napus resistance genes

Plant Protection Science ◽

10.17221/10343-pps ◽

2002 ◽

Vol 38 (SI 1 - 6th Conf EFPP 2002) ◽

pp. S155-S157

Author(s):

C.E. Jenner ◽

F. Sánchez ◽

K. Tomimura ◽

K. Ohshima ◽

F. Ponz ◽

...

Keyword(s):

Brassica Napus ◽

Mosaic Virus ◽

Resistance Gene ◽

Resistance Genes ◽

Infectious Clone ◽

Turnip Mosaic Virus ◽

Viral Fitness ◽

Virulence Determinants ◽

Similar Strategy ◽

Napus Line

Dominant resistance genes identified in Brassica napus lines are effective against some, but not all, Turnip mosaic virus (TuMV) isolates. An infectious clone of an isolate (UK 1) was used as the basis of chimeric virus constructions using resistance-breaking mutants and other isolates to identify the virulence determinants for three dominant resistance genes. For the resistance gene TuRB01, the presence of either of two mutations affecting the cylindrical inclusion (CI) protein converted the avirulent UK 1 to a virulent isolate. Acquisition of such mutations had a slight cost to viral fitness in plants lacking the resistance gene. A similar strategy is being used to identify the virulence determinants for two more resistance genes present in another B. napus line.

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An important determinant of the ability of Turnip mosaic virus to infect Brassica spp. and/or Raphanus sativus is in its P3 protein

Journal of General Virology ◽

10.1099/vir.0.79825-0 ◽

2004 ◽

Vol 85 (7) ◽

pp. 2087-2098 ◽

Cited By ~ 83

Author(s):

Noriko Suehiro ◽

Tomohide Natsuaki ◽

Tomoko Watanabe ◽

Seiichi Okuda

Keyword(s):

Mosaic Virus ◽

Raphanus Sativus ◽

Systemic Infection ◽

Turnip Mosaic Virus ◽

Progeny Virus ◽

Cdna Clones ◽

Coding Region ◽

Terminal Sequence ◽

Long Distance ◽

Chlorotic Mottle

Turnip mosaic virus (TuMV, genus Potyvirus, family Potyviridae) infects mainly cruciferous plants. Isolates Tu-3 and Tu-2R1 of TuMV exhibit different infection phenotypes in cabbage (Brassica oleracea L.) and Japanese radish (Raphanus sativus L.). Infectious full-length cDNA clones, pTuC and pTuR1, were constructed from isolates Tu-3 and Tu-2R1, respectively. Progeny virus derived from infections with pTuC induced systemic chlorotic and ringspot symptoms in infected cabbage, but no systemic infection in radish. Virus derived from plants infected with pTuR1 induced a mild chlorotic mottle in cabbage and infected radish systemically to induce mosaic symptoms. By exchanging genome fragments between the two virus isolates, the P3-coding region was shown to be responsible for systemic infection by TuMV and the symptoms it induces in cabbage and radish. Moreover, exchanges of smaller parts of the P3 region resulted in recombinants that induced complex infection phenotypes, especially the combination of pTuC-derived N-terminal sequence and pTuR1-derived C-terminal sequence. Analysis by tissue immunoblotting of the inoculated leaves showed that the distributions of P3-chimeric viruses differed from those of the parents, and that the origin of the P3 components affected not only virus accumulation, but also long-distance movement. These results suggest that the P3 protein is an important factor in the infection cycle of TuMV and in determining the host range of this and perhaps other potyviruses.

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Improving initial infectivity of the Turnip mosaic virus (TuMV) infectious clone by an mini binary vector via agro-infiltration

Botanical Studies ◽

10.1186/1999-3110-54-22 ◽

2013 ◽

Vol 54 (1) ◽

Cited By ~ 4

Author(s):

Yen-Yu Lin ◽

Meng-Mei Fang ◽

Pin-Chun Lin ◽

Ming-Tzu Chiu ◽

Li-Yu Liu ◽

...

Keyword(s):

Mosaic Virus ◽

Binary Vector ◽

Infectious Clone ◽

Turnip Mosaic Virus ◽

Initial Infectivity

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Photosynthetic responses of radish (Raphanus sativus var. longipinnatus) plants to infection by turnip mosaic virus

Photosynthetica ◽

10.1007/s11099-005-0073-3 ◽

2005 ◽

Vol 43 (3) ◽

pp. 457-462 ◽

Cited By ~ 12

Author(s):

Y. P. Guo ◽

D. P. Guo ◽

Y. Peng ◽

J. S. Chen

Keyword(s):

Mosaic Virus ◽

Raphanus Sativus ◽

Turnip Mosaic Virus ◽

Photosynthetic Responses

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Phosphorylation of the Termini of Cauliflower mosaic virus Precapsid Protein Is Important for Productive Infection

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-20-6-0648 ◽

2007 ◽

Vol 20 (6) ◽

pp. 648-658 ◽

Cited By ~ 15

Author(s):

Julie Champagne ◽

Marie-Eve Laliberté-Gagné ◽

Denis Leclerc

Keyword(s):

Amino Acids ◽

Mosaic Virus ◽

Infectious Clone ◽

Cauliflower Mosaic Virus ◽

Productive Infection ◽

Amino Acid Substitutions ◽

Symptom Development ◽

Protein Precursor ◽

C Terminus

Cauliflower mosaic virus (CaMV) coat protein precursor (pre-CP) has 489 amino acids (p57) and is processed by the viral proteinase into three major forms: p44, p39, and p37. The N- and C-terminal extensions of pre-CP are released during maturation by the virus-encoded proteinase. We showed that these extensions are phosphorylated at several sites by host casein kinase II (CKII). We have identified the phosphorylated amino acids using an in vitro phosphorylation assay and tested the effect of mutation of these sites on viral infectivity. Mutation of serines S66, S68, and S72 to alanine in the N-terminal extension abolished phosphorylation of the protein in vitro. Also, mutation of all S and T residues in the C-terminus (450 to 489) made this region insensitive to CKII. Amino acid substitutions also were introduced into a full-length infectious clone of CaMV. Mutated forms of the virus with S66, S68, and S72 substituted with A or D showed a delay in symptom development and affected the infectivity of the virus. However, a mutant with an A substitution of all the S and T residues of the C-terminal extension of CP was not infectious. These results suggest that phosphorylation of the N- and C-termini of CaMV pre-CP plays an important role in the initiation of viral infection.

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