tobacco mosaic virus n.
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Tobacco mosaic virus

Tobacco mosaic virus

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Tobacco mosaic virus

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  1. Tobacco mosaic virus M.M. Hernandez

  2. Tobacco mosaic virusTMV • Genus Tobamovirus 15 members naked, rigid rod, + unsegmented ss RNA • No family assignation by ICTV

  3. 2 nm 18 nm NC protein STRUCTURAL FEATURES OF TMV CAPSID 30 nm Helical symmetry RNA genome Images:P. Sforza, 2001

  4. TMV genome organization 6,395 nt Capsid CP Replicase RdRp tRNAhis 183K 17.6 K 30 K UAG (leaky) Movement MP MT-Hel 5’ cap 126 K

  5. Host:Nicotiana tabaccum(Solanaceous ) & other 9 plant families susceptible too

  6. Disease:Mosaic (calico)

  7. Mosaic disease on Tobacco leaf

  8. Chlorosis Necrosis Stunting Mosaic disease: significant losses in yield & $ value

  9. TMV Life cycle 5’ 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

  10. TMV Life cycle (cont.) 5’ 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

  11. 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

  12. TMV Life cycle (cont.) h) MP combines with viral +RNA to move it into new plant cells through plasmodesmata

  13. 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

  14. TMV Life cycle (cont.) j) massive TMR replication occur in the X-bodies (viroplasmas) Szecsi et al. 1999 Hamacher et al. 2003

  15. TMV Life cycle (cont.) k) Virus will remain in plant tissue and sap until delivered to a new plant host usually by mechanical means

  16. TMV diagnosis • Symptoms • E.M. & Serology • RT-PCR & RFLP Letschert et al. 2002 HTTP;//BAKERLAB.BERKELEY.EDU/?IMG=1

  17. Current Research on TMV • Improving diagnostic techniques • Characterization of MP and viral movement through plant • Characterization of the Helicase & RdRp

  18. Questions?

  19. 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. 117:137-144 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 Westcott=s Plant Disease Handbook Six Edition. Kluwer Academic Plublishers.Boston pp:511-513 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. Tobacco mosaic virus (vulgare strain; ssp. NC82 strain). Retrieved November 22, 2002, from: 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

  20. 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. pp:377-429 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 106:1-10 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. pp:207-225 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

  21. 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