TMV Full Form

TMV is a single-stranded RNA virus that infects many plants, including tobacco and other members of the Solanaceae family. The infection generates distinctive patterns on the leaves, such as “mosaic”-like mottling and yellowing (hence the name). The first virus identified was TMV. Although a non-bacterial infectious illness had been causing damage to tobacco crops since the late 1800s, it was not until 1930 that the contagious culprit was identified as a virus. It is the first virus to be recognised as a pathogen.

TMV Full Form

The full form of TMV is Tobacco mosaic virus. TMV is called after one of the first plants where it was discovered in the 1800s: tobacco. It may, however, infect over 350 distinct plant species. TMV comprises a nucleic acid molecule (ribonucleic acid; RNA) and a protein covering. A sub-microscopic, hard, rod-shaped particle contains the whole virus. The protein cover breaks away once inside the plant cell. The nucleic acid component commands the plant cell to create more viral nucleic acid and virus protein, interrupting the cell’s everyday activities. TMV can only proliferate within a live cell. Still, it may remain latent in dead tissue for years, allowing it to infect developing plants even after the infected plant portion has died. When plant tissue dies, most other viruses die as well.

Structure of TMV

TMV comprises a nucleic acid molecule (ribonucleic acid; RNA) and a protein covering. A sub-microscopic, hard, rod-shaped particle contains the whole virus. The protein cover breaks away once inside the plant cell. The nucleic acid component commands the plant cell to create more viral nucleic acid and virus protein, interrupting the cell’s everyday activities. Each protein monomer contains three RNA nucleotides. TMV can only proliferate within a live cell. Still, it may remain latent in dead tissue for years, allowing it to infect developing plants even after the infected plant portion has died. Its capsid comprises 2130 molecules of coat protein and one molecule of 6400-base-long genomic single-strand RNA. The protein monomer shall consist of 158 amino acids organised into four primary alpha helices connected by a conspicuous loop near the virion’s axis. Virions have a length of 300 nm and a diameter of 18 nm.

Mechanical Transmission

TMV is mainly transferred from plant to plant by employees’ hands, clothes, and tools. The vegetative proliferation of affected plants spreads TMV and other viral infections. Except for a few cells at the terminals of the growth points, virus particles may be detected throughout the plant. Infected stock plants should be thrown out right away.

Symptoms of TMV

The symptoms vary depending on the plant type affected and the surrounding circumstances. Environmental factors can exacerbate symptoms in certain situations, while others might obscure or conceal them. TMV infections cause a variety of symptoms:

• stunting
• bright and dark green (or yellow and green) mosaic pattern on leaves
• malformation of leaves or growth tips 
• yellow streaking of leaflets (particularly monocots)
• yellow spots on leaves
• distinct yellowing only of veins

High temperatures, insect feeding, growth regulators, herbicides, mineral deficits, and mineral excesses can all induce some of the symptoms above. TMV infections cannot be identified only based on symptoms.

Multiplication and Infection

The replication of viral RNA is required for TMV reproduction or multiplication. Most plants have RNA-dependent RNA Polymerases, which aid in viral RNA replication. There are four TMV-specific proteins known to be produced. TMV viral RNA functions as mRNA in the complicated creation of messenger. They immediately assemble into a complete TMV virion when the coat protein and RNA genome are produced. The protomere combine to create discs composed of two layers of protomere organised in a helical spiral. It reaches nearby cells through plasmodesmata after proliferation. TMV generates P30, a 30 kDa movement protein that enlarges the plasmodesmata and allows them to enter smoothly. TMV is most likely spread across cells as a combination of RNA, P30, and replicate proteins.

It can also spread through the plant’s phloem for longer distance transport. TMV may also be passed from one plant to another by direct touch. Even though TMV has no established transmission vectors, the virus may be easily spread from infected hosts to healthy plants through human contact.

Treatment and Managing TMV

A virus-infected plant can’t be cured with chemicals.

• Buy virus-free plants.
• Remove any weeds, as they may contain TMV.
• Clean the benches and greenhouse framework of all crop waste.
• Identify plants with the symptoms listed above and get a diagnosis.
• Throw away diseased plants.
• Disinfect instruments by soaking them for at least 10 minutes in disinfectant. Using tap water, thoroughly rinse. Wipe vigorously with one of these products to disinfect doorknobs and other greenhouse structures that may have been contaminated.

• Conclusion

  TMV was the first virus to be crystallised, have its shape and structure understood and have its coat protein sequenced. In the 1950s, experiments with TMV RNA proved that viral nucleic acid is the carrier of viral infectivity. A plant affected by the TMV virus can’t be cured with chemicals.