scholarly journals Multiple aromatic amino acids are involved in potyvirus movement by forming π-stackings to maintain coat protein accumulation

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Zhi-Yong Yan ◽  
Xiao-Jie Xu ◽  
Le Fang ◽  
Chao Geng ◽  
Yan-Ping Tian ◽  
...  
Keyword(s):  
Coat Protein ◽  
Mosaic Virus ◽  
Infectious Clone ◽  
Three Dimensional ◽  
Cell Movement ◽  
Systemic Infection ◽  
Watermelon Mosaic Virus ◽  
Protein Accumulation ◽  
Three Dimensional Model ◽  
Aromatic Residues

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.

scholarly journals Residues R192 and K225 in RNA-binding pocket of tobacco vein banding mosaic virus CP control virus cell-to-cell movement and replication

2021 ◽  
Author(s):  
Zhi-Yong Yan ◽  
Xiao-Jie Xu ◽  
Le Fang ◽  
De-Jie Cheng ◽  
Yan-Ping Tian ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Rna Binding ◽  
Cell Movement ◽  
Binding Pocket ◽  
Binding Activity ◽  
Watermelon Mosaic Virus ◽  
Wild Type ◽  
Three Dimensional Model ◽  
Mobility Shift ◽  
Virus Particles

Potyviruses move to neighboring cells in the form of virus particles or coat protein (CP)-containing ribonucleoprotein complex. However, the precise roles of RNA binding residues in potyviral CP in viral cell-to-cell movement remain to be elucidated. In this study, we predicted the three-dimensional model of tobacco vein banding mosaic potyvirus (TVBMV)-encoded CP and found nine residues presumably located in the CP RNA-binding pocket. Substitutions of the two basic residues at positions of 192 and 225 (R192 and K225) either with alanine, cysteine, or glutamic acid abolished TVBMV cell-to-cell and systemic movement in Nicotiana benthamiana plants. These substitutions also reduced the replication of the mutant viruses. Results from the electrophoretic mobility shift assay showed that the RNA binding activity of mutant CPs derived from R192 or K225 substitutions was significantly lower than that of wild-type CP. Analysis of purified virus particles showed that mutant viruses with R192 or K225 substitutions formed RNA-free virus-like particles. Mutations of R192 and K225 did not change the CP plasmodesmata localization. The wild-type TVBMV CP could rescue the deficient cell-to-cell movement of mutant viruses. Moreover, deletion of any of the other seven residues also abolished TVBMV cell-to-cell movement and reduced the CP-RNA binding activity. The corresponding nine residues in watermelon mosaic virus CP were also found to play essential roles in virus cell-to-cell movement. In conclusion, residues R192 and K225 in the CP RNA-binding pocket are critical for viral RNA binding and affect both virus replication and cell-to-cell movement.

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

2003 ◽  
Vol 93 (11) ◽  
pp. 1445-1451 ◽  
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.

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

1999 ◽  
Vol 12 (7) ◽  
pp. 628-632 ◽  
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.

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

2001 ◽  
Vol 75 (17) ◽  
pp. 8045-8053 ◽  
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.

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

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.

scholarly journals Evaluation of ‘AU-Performance’ Watermelon for Its Response to Virus Inoculation

2009 ◽  
Vol 19 (3) ◽  
pp. 609-612 ◽  
Author(s):  
John F. Murphy ◽  
Fenny Dane
Keyword(s):  
Mosaic Virus ◽  
Fungal Pathogens ◽  
Citrullus Lanatus ◽  
Zucchini Yellow Mosaic Virus ◽  
Systemic Infection ◽  
Yellow Mosaic Virus ◽  
Watermelon Mosaic Virus ◽  
Susceptible Parent ◽  
Resistant Parent ◽  
Systemic Symptoms

The watermelon (Citrullus lanatus var. lanatus) ‘AU-Performance’ was developed for resistance to multiple fungal pathogens and the plant virus, zucchini yellow mosaic virus (ZYMV). A greenhouse-based evaluation was carried out to determine the response of ‘AU-Performance’ to inoculation with three important cucurbit (Cucurbitaceae) viruses in the genus Potyvirus: papaya ringspot virus (PRSV), watermelon mosaic virus (WMV), and ZYMV. The evaluation included the resistant parent (PI595203), the susceptible parent (‘AU-Producer’), and varieties AU-Allsweet and Charleston Gray. Each of the three viruses systemically infected ‘AU-Performance’ with 100% infection and development of characteristic systemic symptoms. The susceptible parent (‘AU-Producer’), ‘AU-Allsweet’, and ‘Charleston Gray’ responded similarly with 100% infection and systemic symptoms. In contrast, the resistant parent (PI595203) was resistant to WMV and ZYMV; however, PRSV-inoculated plants developed a systemic infection with accompanied symptoms and high levels of PRSV accumulation in noninoculated leaves. PI595203 was shown in previous studies to be resistant to PRSV. We show in this report that under greenhouse conditions and application of virus by mechanical inoculation, ‘AU-Performance’ was not resistant to infection by the three potyviruses.

scholarly journals Reciprocal function of movement proteins and complementation of long-distance movement of Cymbidium mosaic virus RNA by Odontoglossum ringspot virus coat protein

2005 ◽  
Vol 86 (5) ◽  
pp. 1543-1553 ◽  
Author(s):  
Prabha Ajjikuttira ◽  
Chiang-Shiong Loh ◽  
Sek-Man Wong
Keyword(s):  
Coat Protein ◽  
Transgenic Plants ◽  
Mosaic Virus ◽  
Cell Movement ◽  
Ringspot Virus ◽  
Deficient Mutant ◽  
Long Distance ◽  
Cymbidium Mosaic Virus ◽  
Odontoglossum Ringspot Virus ◽  
Long Distance Movement

Complementation of movement and coat proteins of the orchid-infecting potexvirus Cymbidium mosaic virus (CymMV) and tobamovirus Odontoglossum ringspot virus (ORSV) was investigated. Nicotiana benthamiana, which is susceptible to both CymMV and ORSV, was used as a model system. Four transgenic lines, each harbouring one of the movement protein (MP) or coat protein (CP) genes of CymMV or ORSV, were constructed. The MP of CymMV consists of three overlapping open reading frames, together called the triple-gene block (TGB). CymMV and ORSV mutants, each carrying an inactivated MP or CP, were generated from the respective biologically active full-length cDNA clones. Complementation was studied by infecting transgenic plants with in vitro transcripts generated from these mutants. The cell-to-cell movement of a movement-deficient CymMV was restored in transgenic plants carrying the ORSV MP transgene. Similarly, CymMV TGB1 transgenic plants were able to rescue the cell-to-cell movement of a movement-deficient ORSV mutant. ORSV CP transgenic plants supported systemic movement of a CymMV CP-deficient mutant. However, in these plants, neither encapsidation of CymMV RNA with ORSV CP nor CymMV CP expression was detected. Long-distance movement of an ORSV CP-deficient mutant was not supported by CymMV CP. The complementation of MPs and CPs of CymMV and ORSV facilitates movement of these viruses in plants, except for long-distance movement of ORSV RNA by CymMV CP.

scholarly journals Maintenance of coat protein N-terminal net charge and not primary sequence is essential for zucchini yellow mosaic virus systemic infectivity

2004 ◽  
Vol 85 (11) ◽  
pp. 3421-3430 ◽  
Author(s):  
Boaz Kimalov ◽  
Amit Gal-On ◽  
Ran Stav ◽  
Eduard Belausov ◽  
Tzahi Arazi
Keyword(s):  
Coat Protein ◽  
Mosaic Virus ◽  
Zucchini Yellow Mosaic Virus ◽  
Cell Movement ◽  
Yellow Mosaic Virus ◽  
Virus Infectivity ◽  
Amino Acid Residues ◽  
Primary Sequence ◽  
Net Charge ◽  
Truncation Mutant

Zucchini yellow mosaic virus (ZYMV) surface exposed coat protein (CP) N-terminal domain (Nt) is 43 aa long and contains an equal number of positively and negatively charged amino acid residues (CP-Nt net charge=0). A ZYMV-AGII truncation mutant lacking the first 20 aa of its CP-Nt (AGII-CPΔ20; CP-Nt net charge=+2) was found to be systemically non-infectious even though AGII mutants harbouring larger CP-Nt deletions were previously demonstrated to be fully infectious. Nevertheless, AGII-CPΔ20 infectivity was restored by fusion to its CP-Nt two Asp residues or a negatively charged Myc peptide, both predicted to neutralize CP-Nt net positive charge. To evaluate further the significance of CP-Nt net charge for AGII infectivity, a series of CP-Nt net charge mutants was generated and analysed for systemic infectivity of squash plants. AGII-CPKKK harbouring a CP-Nt amino fusion of three Lys residues (CP-Nt net charge=+3) was not systemically infectious. Addition of up to four Asp residues to CP-Nt did not abolish virus infectivity, although certain mutants were genetically unstable and had delayed infectivity. Addition of five negatively charged residues abolished infectivity (AGII-CPDDDDD; CP-Nt net charge=−5) even though a recombinant CPDDDDD could assemble into potyviral-like particle in bacteria. Neutralization of CP-Nt net charge by fusing Asp or Lys residues recovered infectivity of AGII-CPKKK and AGII-CPDDDDD. GFP-tagging of these mutants has demonstrated that both viruses have defective cell-to-cell movement. Together, these findings suggest that maintenance of CP-Nt net charge and not primary sequence is essential for ZYMV infectivity.

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