Tobacco mosaic virus (TMV) is a plant virus that belongs to the genus Tobamovirus. It is named so because it majorly infects tobacco plants, potatoes, tomatoes and other members of the Solanaceae family. The infection creates a mosaic like pattern, mottling and discoloration of the leaves.

1. Tobacco Mosaic Virus and
Papaya Leaf Curl
Presented By
Priyanka Baghel
MSC IV Sem.

2. Content
 Tobacco Mosaic Disease
• Discovery of Tobacco Mosaic
• Structure of Tobacco mosaic virus
• Host plant
• Casual organism
• Life cycle
• Disease cycle
• Symptoms
• Disease Management
 Papaya mosaic Disease
• causal organism
• Symptoms
• Management
 Papaya leaf curl Disease
• Casual organism
• Disease transmission
• Symptoms
• Control Measures
• Reference

3. Introduction of Tobacco mosaic virus
• Tobacco mosaic virus, TMV is a plant
virus that belong to genus tobamo
virus
• It is name so because is majorly
infected, tobacco, plants, potatoes,
tomatoes, and other members of the
solanaceae family
• The infection creates a Mosaic like
pattern, mottling and discolouration
of the leaves

4. Discovery, tobacco mosaic
• Adolf mayer a germane chemistry first started studying the disease in tobacco
plant in 1879 by 1886 he was able to describe how leaf Mottling disease was
able to transfer from infected plants to healthy plants by rubbing infected
plants juice over the healthy one similar to bacterial infection

5. structure of tobacco mosaic
• The tobacco mosaic virus TMV has rod
like appearance that is 300 nm long
with a diameter of 18 nm
• It is a covered by a protein shell called
capsid that enclose the virus, genetic
material
• The genetic material is a single
standard RNA molecules
• The capsid is made up of 2130
molecules of coat proteins, that
assemble in a rod like helical structure,
processing, 16.3 proteins per helix turn
• The RNA is found in a coiled manner
inside the capsid coat and is made up
of approximately 6395 nucleotide

6. Host plant
• it is known to infect members of nine plant families of 125 individual species
• it including tobacco, tomato pepper , call member of the useful solanaceae ,
cucumbers and a number of ornamental flowers
• Host plants include
• Tobacco
• Tomato
• Potato
• Pepper
• Beef
• Melon
• Cucumber
• Squash
• Lettuce
• Many host are symptoms less

7. causal organism
• It is caused by Nicotiana virus 1 and its molecular
weight is 39 million dalton
• It is rod shaped gram positive measuring about 300A
length and 180A diameter
• it is made up of central place. Ribonucleic acid
molecules covered with a protein coat call capsid
• The protein subunit 94% is composed of single chain
of 158 amino acid reduced of know sequence
• The folding of the chain is ellipsoid with an axial ratio
of 3:1
• The RNA 5.6% is single stranded, molecular weight is
2.4 million Daltons and helix radius of 40 A. Than can
be seen under electron microscope.

8. Life Cycle
• The virus gets inside the plant hostel via vector, such as a aphids , files,
and other insect
• after entering the host cell, the virus starts to multiply and spreads to
the Nearby cells via plasmademato
• The virus can be transmitted to other healthy plants by coming indirect
contact with infected plants
• For replication and multiplication inside the host cells the viral particle
release its genomic material
• The ssRNA, then translates multiple mRNAs that can replicate in viral
genome and capsid proteins
• All these proteins assemble to from a newly synthesised cell for tobacco
mosaic virus is Ready to infect, another cells

9. Disease cycle
• primary infection
• Secondary infection
Primary infection
• Transplant are handle by worker whose hands are contaminated by virus enter
into host cells through wounds, replicate spread throughout the plant and
cause disease
secondary inspection
• it occurs after transmission during the Suckering of tobacco and other culture
practices
• It continue throughout the seasons resulting in servere infection

10. • The virus is sap transmissible and enter through wounds
• no insect vector is non to transmit this virus
• Easily transmitted in field by mechanical means and by wind and water

11. Disease management
• no chemical cure, virus infected plant
• Purchase is virus free plants
• The field should be weed, truly and regular roughing should be done
• Genetic engineering also possible in which N gene is responsible for resistance
to TMV
• The N. Gene is transferred into nicotiana tobacum and nicotine glutinosa
• The interaction of N gene product will TMB a hypersensitive reaction occurs
which cause the plant to kill it own cell at any point where the virus entered

12. symptoms of tobacco mosaic
• light discolouration along the Veinus of
the youngest leaves
• Later turn into dark green pattern
associated with veinus
• Ring spots
• Stunding growth
• Premature death of plant

13. Papaya Leaf Curl Disease

14. papaya leaf curl virus
• Host: Carica papaya L. (papaya)
• Disease Name: papaya leaf curl
• Pathogen Name : papaya leaf curl virus (PLCV) ,a
Begomovirus
• Papaya leaf car was first reported in Tamil Nadu
in 1939
• Is a DNA virus from the gene Begomovirus and
the family Geminiviridae
• Papaya, (carica papaya), but can sometimes
infect other crops such as tobacco or tomato

15. • it can be found in tropical and subtropical regions primary in India but closely
related species have also been detected in countries such as China, Malaysia,
Nigeria and South Korea
• This virus is transmitted by an insect vector from the family Aleyrodidae and
order Hemiptera, the white fly Bemisia tabaci

16. casual organism
• papaya leaf, curl virus is DNA virus
• This virus belong to begomovirus of the Geminiviridae family
• Genome of the virus is a Bipartile single stranded circular, DNA molecules
(2400 -2800) nucleotide
• The genome codes for the coat proteins and 5 to 7 multifunctional protein
needed for the replication, transmission movement and pathogenesis

17. Disease transmission
• virus need a suitable vector for transmission
• Papaya leaf car virus is a transmitter
through the vector white fly ( Bemisia
tabaci)
• Infected , seeds, seedling and grafting
material
• The virus cannot be transferred mechanical
means as in the case of mosaic disease

18. symptom of PLCV
• curling crinkling and distortion of leaves
Reduction of leave, lamina, rolling of leave
margins and ward and downward thickening of
Veins
• Leaves become Leathery, brittle and distorted
• Plant stunted
• Affected plant does not produce flower and
fruits
• Spread by white fly Bemisia tabaci
• Sometimes all the leaves at the top of the
plants are affected by the symptoms

19. prevention
• immediately after the disease is noticed, the plant must be rooted
and destroyed
• Spray insecticide for vector control

20. Reference
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