Presentation covers the introduction of TMV, host range Adaptability, symptoms and its controll

1. Tobacco Mosaic
Virus
(TMV)
Submitted by: Nimra Nadeem
FAS, University of the Punjab lahore.

2. Introduction of TMV
● First virus crystallized in 1935 by W.
M Stanley in USA.
● TMV is the Type member of the genus
Tobamovirus and family Virgaviridae.
● Most serious pathogen.
● Most resistant virus having thermal
death point of 90° for 10 min.
●

3. Structure of TMV
● Franklin in 1957 described its
structure.
● ssRNA Rod shaped helical virus.
● 300nm in length, 18nm in dia and
weighs 39million daltons.
● Virion is made up of 2130 protein
subunits and 158 amino acids in each
subunit.
● It's ssRNA contains 6400 nucleotides.

4. Host range
Over 200 plant species in 11 families are known to be host.
Hosts include:
● Tobacco
● Tomato
● Potato
● Pepper
● Beet
● Melon
● Cucumber
● Squash
● Lettuce
● Many hosts are Symptomless.

5. Transmission
● Mechanically
● By incidental contact and wounding
● Don't transmit by vector
● By handling contaminated tobacco
products or infected plants and then
healthy susceptible one. From the
point of entrance virus moves from
cell to cell through plasmodesmata,
multiplies in and infects each cell &
when it reaches the phloem travels
systemically and infects the entire
plant
● Also transmitted by wind and water.
●

6. Adaptability of virus
● TMV exists in numerous strains which differ from one another in one or more characters.
● Exceptionally stable: exists over seasons in infected tobacco stalks and leaves in the soil,
on the surface of contaminated seeds and for many years on cigarettes etc.
● Prevalent in many Ornamentals in green houses and botanical gardens

7. Symptoms of TMV
TMV can cause symptoms including:
● Mosaic stunting. Mottling
Malformation of leaves and growing points
Rugosity. Curling
Yellow streaking.
Yellow spotting
Vein clearing
Necrotic leaf spot

8. Symptoms of TMV

9. Controll of TMV
● Sanitation: Removing of infected parts then washing hands and avoiding planting
susceptible host for two years in the field where diseased crop was grown.
● Growing disease resistant varieties
● Crop rotation
● Growing genetically modified crop
● By spraying or Dipping plants in milk which inhibits infection by TMV.

10. Thanks