Coding Changes in the 3a Cell-to-Cell Movement Gene Can Extend the Host Range of Brome Mosaic Virus Systemic Infection

AbstractCoat protein (CP) is required for potyviruses to move and establish a systemic infection in plants. π-stackings formed by aromatic residues play critical roles in maintaining protein stability and functions. As we know, many aromatic residues located in the core region of potyvirus CPs are conserved. However, their roles in potyvirus infection remain largely unknown. Here, through analysis of the three-dimensional model of the tobacco vein banding mosaic virus (TVBMV; genus Potyvirus) CP, 16 aromatic residues were predicated to form π-stackings. The results of transient expression experiments demonstrated that deletion of any of these 16 aromatic residues reduced CP accumulation. Infectivity assays showed that deletion of any of these aromatic residues in the TVBMV infectious clone abolished cell-to-cell movement and reduced replication of the virus. Substitution of Y105 and Y147 individually with non-aromatic residues alanine or glycine reduced CP accumulation, virus replication, and abolished the ability of TVBMV to move intercellularly, while substitution of these two residues individually with aromatic residues phenylalanine or tryptophan, had no or little effect on CP accumulation and TVBMV systemic movement and replication. Similar results were obtained from the CP mutants of watermelon mosaic virus (WMV, genus Potyvirus). Taken together, our results demonstrate that multiple aromatic residues in CP are involved in potyvirus movement by forming π-stackings to maintain CP accumulation.

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Cucumber mosaic virus Establishes Systemic Infection at Increased Temperature Following Viral Entrance Into the Phloem Pathway of Tetragonia expansa

Phytopathology ◽

10.1094/phyto.2003.93.11.1445 ◽

2003 ◽

Vol 93 (11) ◽

pp. 1445-1451 ◽

Cited By ~ 5

Author(s):

Takashi Kobori ◽

Takeshi Osaki ◽

Satoshi T. Ohki

Keyword(s):

Cucumber Mosaic Virus ◽

Mosaic Virus ◽

Cell Movement ◽

Systemic Infection ◽

Regulatory Site ◽

Mesophyll Cells ◽

Increased Temperature ◽

Tetragonia Expansa ◽

Internal Phloem

A potential regulatory site for Cucumber mosaic virus (CMV, pepo strain) movement necessary to establish systemic infection was identified through immunological and hybridization studies on Tetragonia expansa, which was systemically infected by CMV at 36°C but not at 24°C. In inoculated leaves, cell-to-cell movement of CMV was enhanced at 36°C compared with that observed at 24°C. CMV was distributed in the phloem cells of minor veins as well as epidermal and mesophyll cells at both 36 and 24°C. CMV was detected in the petioles of inoculated leaves, stems, and petioles of uninoculated upper leaves at 36°C, whereas CMV was detected only in the petioles of inoculated leaves and in stems at 24°C. CMV moved into the phloem and was transported to the stem within 24 h postinoculation (hpi) at 36°C. However, it did not accumulate in the petioles of the upper leaves until 36 hpi. In petioles of inoculated leaves at 24°C, CMV was detected in the external phloem but not in the internal phloem. From these results, we conclude that systemic infection is established after viral entrance into the phloem pathway in T. expansa at 36°C.

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The Rate of Cell-to-Cell Movement in Squash of Cucumber Mosaic Virus Is Affected by Sequences of the Capsid Protein

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.1999.12.7.628 ◽

1999 ◽

Vol 12 (7) ◽

pp. 628-632 ◽

Cited By ~ 34

Author(s):

Sek-Man Wong ◽

Sharon Swee-Chin Thio ◽

Michael H. Shintaku ◽

Peter Palukaitis

Keyword(s):

Amino Acids ◽

Cucumber Mosaic Virus ◽

Mosaic Virus ◽

Capsid Protein ◽

Cell Movement ◽

Systemic Infection ◽

Long Distance ◽

Local Movement ◽

Long Distance Movement

The M strain of cucumber mosaic virus (CMV) does not infect squash plants systemically and moves very slowly in inoculated cotyledons. Systemic infection and an increase in the rate of local movement were observed when amino acids 129 or 214 of the M-CMV capsid protein (CP) were altered to those present in the Fny strain of CMV. While the opposite alterations to the CP of Fny-CMV inhibited systemic infection of squash, they did not show the same effects on the rates of both cell-to-cell and long-distance movement. However, the ability of CMV to infect squash systemically was affected by the rate of cell-to-cell movement.

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Systemic Infection of Cowpea by Two Isolates of Brome Mosaic Virus

Plant Disease ◽

10.1094/pd-71-0557c ◽

1987 ◽

Vol 71 (6) ◽

pp. 557 ◽

Cited By ~ 2

Author(s):

R. A. Valverde

Keyword(s):

Mosaic Virus ◽

Systemic Infection ◽

Brome Mosaic Virus

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Conversion in the Requirement of Coat Protein in Cell-to-Cell Movement Mediated by the Cucumber Mosaic Virus Movement Protein

Journal of Virology ◽

10.1128/jvi.75.17.8045-8053.2001 ◽

2001 ◽

Vol 75 (17) ◽

pp. 8045-8053 ◽

Cited By ~ 47

Author(s):

Hideaki Nagano ◽

Kazuyuki Mise ◽

Iwao Furusawa ◽

Tetsuro Okuno

Keyword(s):

Amino Acids ◽

Coat Protein ◽

Cucumber Mosaic Virus ◽

Mosaic Virus ◽

Movement Protein ◽

Cell Movement ◽

Plant Viruses ◽

Brome Mosaic Virus ◽

Viral Movement ◽

Intercellular Movement

ABSTRACT Plant viruses have movement protein (MP) gene(s) essential for cell-to-cell movement in hosts. Cucumber mosaic virus (CMV) requires its own coat protein (CP) in addition to the MP for intercellular movement. Our present results using variants of both CMV and a chimeric Brome mosaic virus with the CMV MP gene revealed that CMV MP truncated in its C-terminal 33 amino acids has the ability to mediate viral movement independently of CP. Coexpression of the intact and truncated CMV MPs extremely reduced movement of the chimeric viruses, suggesting that these heterogeneous CMV MPs function antagonistically. Sequential deletion analyses of the CMV MP revealed that the dispensability of CP occurred when the C-terminal deletion ranged between 31 and 36 amino acids and that shorter deletion impaired the ability of the MP to promote viral movement. This is the first report that a region of MP determines the requirement of CP in cell-to-cell movement of a plant virus.

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The Tomato brown rugose fruit virus movement protein overcomes Tm-22 resistance in tomato while attenuating viral transport

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-01-21-0023-r ◽

2021 ◽

Author(s):

Hagit Hak ◽

Ziv Spiegelman

Keyword(s):

Mosaic Virus ◽

Movement Protein ◽

Cell Movement ◽

Systemic Infection ◽

Movement Analysis ◽

Tomato Mosaic Virus ◽

Resistance Response ◽

Global Epidemic ◽

High Durability ◽

C Terminus

Tomato brown rugose fruit virus (ToBRFV) is a new virus of the Tobamovirus genus, causing substantial damage to tomato crops. Reports of recent ToBRFV outbreaks from around the world indicate an emerging global epidemic. ToBRFV overcomes all tobamovirus resistances in tomato, including the durable Tm-22 resistance gene, which had been effective against multiple tobamoviruses. Here, we show that the ToBRFV movement protein (MPToBRFV) enables the virus to evade Tm-22 resistance. Transient expression of MPToBRFV failed to activate the Tm-22 resistance response. Replacement of the original MP sequence of Tomato mosaic virus (ToMV) with MPToBRFV enabled this recombinant virus to infect Tm-22 resistant plants. Using hybrid protein analysis, we show that the elements required to evade Tm-22 are located between MPToBRFV amino acids 1 and 216, and not the C terminus as previously assumed. Analysis of ToBRFV systemic infection in tomato revealed that ToBRFV spreads slower compared to ToMV. Interestingly, replacement of Tobacco mosaic virus (TMV) and ToMV MPs with MPToBRFV caused an attenuation of systemic infection of both viruses. Cell-to-cell movement analysis showed that MPToBRFV moves less effectively compared to the TMV MP (MPTMV). These findings suggest that overcoming Tm-22 is associated with attenuated MP function. This may explain the high durability of Tm-22 resistance, which had remained unbroken for over 60 years.

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Characterization of a Brome mosaic virus Strain and Its Use as a Vector for Gene Silencing in Monocotyledonous Hosts

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-19-1229 ◽

2006 ◽

Vol 19 (11) ◽

pp. 1229-1239 ◽

Cited By ~ 133

Author(s):

Xin Shun Ding ◽

William L. Schneider ◽

Srinivasa Rao Chaluvadi ◽

M. A. Rouf Mian ◽

Richard S. Nelson

Keyword(s):

Gene Silencing ◽

Mosaic Virus ◽

Gene Function ◽

Festuca Arundinacea ◽

Systemic Infection ◽

Brome Mosaic Virus ◽

Expression Vectors ◽

Virus Induced Gene Silencing ◽

Dicotyledonous Plants ◽

Virus Expression

Virus-induced gene silencing (VIGS) is used to analyze gene function in dicotyledonous plants but less so in monocotyledonous plants (particularly rice and corn), partially due to the limited number of virus expression vectors available. Here, we report the cloning and modification for VIGS of a virus from Festuca arundinacea Schreb. (tall fescue) that caused systemic mosaic symptoms on barley, rice, and a specific cultivar of maize (Va35) under greenhouse conditions. Through sequencing, the virus was determined to be a strain of Brome mosaic virus (BMV). The virus was named F-BMV (F for Festuca), and genetic determinants that controlled the systemic infection of rice were mapped to RNAs 1 and 2 of the tripartite genome. cDNA from RNA 3 of the Russian strain of BMV (R-BMV) was modified to accept inserts from foreign genes. Coinoculation of RNAs 1 and 2 from F-BMV and RNA 3 from R-BMV expressing a portion of a plant gene to leaves of barley, rice, and maize plants resulted in visual silencing-like phenotypes. The visual phenotypes were correlated with decreased target host transcript levels in the corresponding leaves. The VIGS visual phenotype varied from maintained during silencing of actin 1 transcript expression to transient with incomplete penetration through affected tissue during silencing of phytoene desaturase expression. F-BMV RNA 3 was modified to allow greater accumulation of virus while minimizing virus pathogenicity. The modified vector C-BMVA/G (C for chimeric) was shown to be useful for VIGS. These BMV vectors will be useful for analysis of gene function in rice and maize for which no VIGS system is reported.

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Natural isolates of Brome mosaic virus with the ability to move from cell to cell independently of coat protein

Journal of General Virology ◽

10.1099/vir.0.80775-0 ◽

2005 ◽

Vol 86 (4) ◽

pp. 1201-1211 ◽

Cited By ~ 8

Author(s):

Atsushi Takeda ◽

Wakako Nakamura ◽

Nobumitsu Sasaki ◽

Kaku Goto ◽

Masanori Kaido ◽

...

Keyword(s):

Coat Protein ◽

Mosaic Virus ◽

Mutational Analysis ◽

Cell Movement ◽

Plant Viruses ◽

Brome Mosaic Virus ◽

Single Amino Acid ◽

In Planta ◽

C Terminus ◽

Natural Isolates

Brome mosaic virus (BMV) requires encapsidation-competent coat protein (CP) for cell-to-cell movement and the 3a movement protein (MP) is involved in determining the CP requirement for BMV movement. However, these conclusions have been drawn by using BMV strain M1 (BMV-M1) and a related strain. Here, the ability of the MPs of five other natural BMV strains to mediate the movement of BMV-M1 in the absence of CP was tested. The MP of BMV M2 strain (BMV-M2) efficiently mediated the movement of CP-deficient BMV-M1 and the MPs of two other strains functioned similarly to some extent. Furthermore, BMV-M2 itself moved between cells independently of CP, demonstrating that BMV-M1 and -M2 use different movement modes. Reassortment between CP-deficient BMV-M1 and -M2 showed the involvement of RNA3 in determining the CP requirement for cell-to-cell movement and the involvement of RNAs 1 and 2 in movement efficiency and symptom induction in the absence of CP. Spontaneous BMV MP mutants generated in planta that exhibited CP-independent movement were also isolated and analysed. Comparison of the nucleotide differences of the MP genes of BMV-M1, the natural strains and mutants capable of CP-independent movement, together with further mutational analysis of BMV-M1 MP, revealed that single amino acid differences at the C terminus of MP are sufficient to alter the requirement for CP in the movement of BMV-M1. Based on these findings, a possible virus strategy in which a movement mode is selected in plant viruses to optimize viral infectivity in plants is discussed.

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Tobamovirus Replicase Coding Region Is Involved in Cell-to-Cell Movement

Journal of Virology ◽

10.1128/jvi.75.18.8831-8836.2001 ◽

2001 ◽

Vol 75 (18) ◽

pp. 8831-8836 ◽

Cited By ~ 72

Author(s):

Kyotaro Hirashima ◽

Yuichiro Watanabe

Keyword(s):

Amino Acid ◽

Amino Acid Sequence ◽

Tobacco Mosaic Virus ◽

Host Range ◽

Mosaic Virus ◽

Movement Protein ◽

Cell Movement ◽

Coding Region ◽

Replicase Proteins ◽

Viral Movement

ABSTRACT Tobacco mosaic virus (TMV) encodes a 30-kDa movement protein (MP) which enables viral movement from cell to cell. It is, however, unclear whether the 126- and 183-kDa replicase proteins are involved in the cell-to-cell movement of TMV. In the course of our studies into TMV-R, a strain with a host range different from that of TMV-U1, we have obtained an interesting chimeric virus, UR-hel. The amino acid sequence differences between UR-hel and TMV-U1 are located only in the helicase-like domain of the replicase. Interestingly, UR-hel has a defect in its cell-to-cell movement. The replication of UR-hel showed a level of replication of the genome, synthesis, and accumulation of MP similar to that observed in TMV-U1-inoculated protoplasts. Such observations support the hypothesis that the replicase coding region may in some fashion be involved in cell-to-cell movement of TMV.

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