Tobacco Mosaic Virus And papaya leaf curl disease

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

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