M.M. Hernandez

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Tobacco mosaic virus

• M.M. Hernandez

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Tobacco mosaic virusTMV

• Genus Tobamovirus
• 15 members
• naked, rigid rod,
• unsegmented ss RNA
• No family assignation by ICTV

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STRUCTURAL FEATURES OF TMV
CAPSID
30 nm
Helical symmetry
RNA genome
ImagesP. Sforza, 2001 www.ppws.vt.edu/sforza/tm
v/tmv.html
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TMV genome organization
5 cap
126 K
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Host Nicotiana tabaccum (Solanaceous ) other
9 plant families susceptible too
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DiseaseMosaic (calico)
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Mosaic disease on Tobacco leaf
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Stunting
Mosaic disease significant losses in yield
value
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TMV Life cycle

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cap
Host Rb
a) Virus entry trough abrasions on plant tissue.
Inside cell associates with ER b) spontaneous
release of few capsid (CP) subunits 5' end of
genome is uncovered c) Host ribosome attaches
to viral RNA, moves down displacing more CP
units
/
Modification of a diagram from L. Stannard,
Department of Medical Microbiology, U. of Cape
Town
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TMV Life cycle (cont.)
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d) Ribosome meets start codon, translates first
two proteins (126K ,183 K) while uncoating
continues co-traslational disassembly e)
126 K ( MET-Hel) 183 K ( RdRp) use viral RNA
as template to make full length complementary
neg. strand RNA
/
Modification of a diagram from L. Stannard,
Department of Medical Microbiology, U. of Cape
Town
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TMV Life cycle (cont.)
RdRp
Strand (genome)
Neg. strand
f) Neg. RNA strand used by viral replicase
(RdPp/MET-Hel ) as template for RNA g) Also,
neg. RNA strand has internal promoters used by
replicase to make mRNA for 30K protein (MP) and
17.5 K (CP)
promoters
Transcription by RdRp
MP mRNA
CP mRNA
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TMV Life cycle (cont.)
h) MP combines with viral RNA to move it into
new plant cells through plasmodesmata
httpwww.sunysb.edu/biochem/BIOCHEM/facultypages/c
itovsky/TMV-TransportModel-III2.jpg
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TMV Life cycle (cont.)
i) Accumulation of RNA CP proteins stimulates
assembly of progeny virions
Viral RNA interacts with discs
CP units self assemble into discs
Electrostatic interaction stabilizes structure
into helix
M. Olvera de la Cruz
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TMV Life cycle (cont.)
j) massive TMR replication occur in the X-bodies
(viroplasmas)
Szecsi et al. 1999
Hamacher et al. 2003
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TMV Life cycle (cont.)
k) Virus will remain in plant tissue and sap
until delivered to a new plant host usually by
mechanical means
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TMV diagnosis

• Symptoms
• E.M. Serology
• RT-PCR RFLP

Letschert et al. 2002
HTTP//BAKERLAB.BERKELEY.EDU/?IMG1
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Current Research on TMV

• Improving diagnostic techniques
• Characterization of MP and viral movement through
  plant
• Characterization of the Helicase RdRp

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Questions?
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REFERENCES
Agrios G. N. 1988. Plant Pathology Third
Edition. Academic Press, Inc. San Diego pp
658663 Ashby J., E. Boutant, M. Seemanpillai, A.
Sambade, C. Ritzenthaler, M. Heinlein. 2006.
Tobacco Mosaic Virus Movement Protein Functions
as a structural Microtubule-Associated Protein.
Journal of Virology. 80(17)8329-8344 Bos L.
1999. Plant Viruses Unique and intriguing
pathogens. Backhuys Publishers Leiden Dovas C.,
K. Efthimious, N. I. Katis. 2004. Generic
detection and differentiation of tobamoviruses by
a spot nested RT-PCR-RFLP using dI-contining
primers along with homologous dG-containing
primers. Journal of Virological Methods.
117137-144 Goelet P., Lomonossoff G. P.,
Blutler P. JG, Akam M. E., Gait M. J., and Karn
J., 1982. Nucleotide sequence of the tobacco
mosaic virus RNA. Proc. Natl. Acad. Sci. U.S.A.
79 5818-5822 Goregaoker S. P. and J. N. Culver.
2003. Oligomerization and Activity of the
Helicase Domain of the Tobacco Mosaic Virus 126-
and 183-Kilodalton Replicase Proteins. Journal of
Virology. 77 (6) 3549- 3556 Hirashima K. and Y.
Watanabe. 2001. Tobamovirus Replicase Coding
Region is Involved in Cell-to-Cell Movement.
Journal of Virology. 75 (18) 8831-8836 Hirashima
K. and Y. Watanabe. 2003. RNA Helicase Doamin of
Tobamovirus Replicase Executes Cell-to-Cell
Movement Possibly through Collaboration with its
Nonconserved Region. Journal of Virology. 77
(22) 12357- 12362 Horst K.R.(reviser), 2001
Westcotts Plant Disease Handbook Six Edition.
Kluwer Academic Plublishers.Boston
pp511-513 Jacobi V., G.D. Bachand, R.C. Hamelin
and J.D. Castello. 1998. Development of a
multiplex immunocapture RT-PCR assay for
detection and differentiation of tomato and
tobacco mosaic tobamoviruses. Journal of
Virological Methods 74 (2)167-178 International
Committee on Taxonomy of Viruses (ICTV) 2002.
ICTVdB Virus Descriptions. 71.0.1.0.001 Tobacco
mosaic virus (vulgare strain ssp. NC82 strain).
Retrieved November 22, 2002, from
http//www.ncbi.nih.gov/ICTVdb/ICTVdB/71010001.htm
Kawakami F. M., R.W. Kim, R.N. Beachy. 2006
Domains of tobacco mosaic virus movement protein
essential for its membrane association. Journal
of General Virology 87(9)2699-7707
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Khan J. A. and J. Dijkstra editors, 2002. Plant
Viruses as Molecular Pathogens Food Product Press
7 An Imprint of the Haworth Press Inc. New
York Lazarowitz S. G., 2001. Plant Viruses In
Fundamental Virology Fourth Edition. Knipe D.
and P.M. Howley Editors. Lippincott Williams
Wilkins, Philadelphia. pp377-429 Lesemann
D.-E., S. Winters. 1998. Detection and specific
identification of tobamoviruses in horticultural
crops by immunoelectron microscopical methods
(IEM) and ELISA. Mitteilungender Biologischen
Bundesanstalt fur Land-und Forstwirtschaft
357 Letschert B., A Gunter, L. Dietrich-Eckhardt,
P. Willingmann, C. Heinze., 2002. Detection and
differentiation of serologically cross-reacting
tobamoviruses of economical importance by RT-PCR
and RT-PCR-RFLP. Journal of Virological Methods
1061-10 Lucas G. B. , C.L. Campbell, and L.T.
Lucas, 1985. Introduction to Plant Diseases
Identification and Management. The AVI
Publishing Company, Inc. Westport Connecticut. pp
254-261 Martin J.H. , W.H. Leonard and D. L.
Stamp 1976 Principles of Field Crop Production
Third Edition MacMills Publishing Co., INC.
London Matthews R.E.F., 1992. Fundamentals of
Plant Virology Academic Press Inc San
Diego Matthews R.E.F., 1999 Plant Virology Third
Edition. Academic Press Inc San Diego.
pp207-225 Osman T. A. M., and K.W. Buck. 2003
Identification of a Region of the Tobacco Mosaic
Virus 126- and 183-Kilodalton Replication
Proteins Which bind Specifically to the Viral
3'-Terminal tRNA-like Structure. Journal of
Virology 77(16 ) 8669-8675 Padmanadban M.S.,
Goregaoker S.P., S. Golem, H. Shiferaw, and J. N.
Culver. 2005. Interaction of the Tobacco Mosaic
Virus Replicase Protein with the Aux/IAA Protein
PAP1/IAA26 Is associated with Disease
Development. Journal of Virology. 79 (4) 2549 -
2558 Sacristan S., J. M. Malpica, A. Fraile, F.
Garcia-Arenal. 2003. Estimation of Population
Bottlenecks during Systemic Movement of Tobacco
Mosaic Virus in Tobacco Plants. Journal of
Virology 77(18) 9906-9911 Seemanpillai M., R.
Elamawi, C. Ritzenthhaler, M. Heinlein. 2006.
Challenging the Role of Microtubules in Tobacco
Mosaic Virus Movement by Drug Treatment is
Disputable. Journal of Virology 80(13) 6712-6715
Torok V.A. and J.W. Randles. 2001. Tobacco
mosaic virus RNA as an internal control for
duplex RT-PCR assay of pea germaplsm. Australian
Plant Pathology 30 227-230 Zaitlin M., 2001.
Tobamovirus in The Spriger Index of Viruses.
Tidona C. A. and G. Darai Editors.
Springer-Verlag, Berlin
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2. Add ssTMV RNA (assembly infective virus)
Electrostatic attraction stabilizes viral
assembly.
1. Solution of TMV Capsid Proteins
Electrostatic repulsion inhibits protein
protein aggregation.
Salt (M)
ZRNA -1/mer
3. Sphere-like (icosahedral) RNA virus (Tsuruta
et al)
Acidity
4. Capsid Hole (density RNA crystal)
self-assembles from capsid protein viral RNA
solution