What is the structure of the Tobacco mosaic virus?

Tobacco mosaic virus (TMV; Tobamovirus, Virgaviridae) is a rodlike virus with a length of 300 nm and diameter of 18 nm. TMV capsids are composed of 2130 identical protein subunits, which assemble around the viral ssRNA to form a helical structure, with a hollow central cavity of 4 nm diameter.

What is the cause of Tobacco mosaic virus?

The tobacco mosaic virus infects tobacco and lots of other closely related species like tomatoes and peppers. It is transmitted by contact between plants, either naturally or on the hands of farmers. It infects the chloroplasts of plant leaves and changes their colour from green to yellow or white in a mosaic pattern.

What is Tobacco mosaic virus simple definition?

Definition of tobacco mosaic virus : a single-stranded RNA virus (species Tobacco mosaic virus of the genus Tobamovirus) that occurs worldwide and causes mosaic disease in plants (such as tobacco and tomato) especially of the nightshade family.

Is TMV helical?

TMV was the first biological structure recognized to be a helical array of identical subunits, and it was the first helical protein structure to be determined at atomic resolution (Fig. 5.10).

How TMV is transmitted and control?

Disease spread TMV is transmitted very easily making control difficult. For example, infected leaves rubbing against healthy plants, or contaminated tools or workers hands (which can become contaminated with virus from cigarettes) can all spread TMV. Unlike most plant viruses, TMV is not transmitted by insects.

How does TMV spread within the plant?

Tobacco mosaic virus is usually spread from plant to plant via ‘mechanical’ wounds caused by contaminated hands, clothing or tools such as pruning shears and hoes. This is because TMV occurs in very high concentrations in most plant cells.

What is the tobacco mosaic virus structure?

The disease is characterized by mottling of leaves referred to as ‘mosaics’. Tobacco Mosaic Virus Structure: The virus has a coat made up of protein which consists of 2130 identical protein sub-units. Each of these sub-units have a molecular weight of 18,000. The sub-unit is composed of a singular chain of known sequence of 158 amino acids.

What are the tobacco mosaic virus symptoms?

Tobacco Mosaic Virus Symptoms: The TMV virus/ viruses attack is confirmed when on the younger leaves of tobacco plants, the veins may show a clear ring, which is later on followed by mottling. With the enlargement of leaves dark green spots of abnormal size appear and at later stage they transformed into crumpled blister areas which are irregular.

How does tobacco mosaic virus (TMV) replicate?

Life-Cycle (Replication) of Tobacco Mosaic Virus (TMV): Plant viruses like TMV penetrate and enter the host cells in toto and their replication completes within such infected host cells (Fig. 13.21). Inside the host cell, the protein coat dissociates and viral nucleic acid becomes free in the cell cytoplasm.

How to control tobacco mosaic disease?

Crop rotation is one of the best ways to control the mosaic disease. Therefore, the tobacco mosaic virus is the most resistant and stable virus that remain infectious even after 50 years of storage. From the name itself, it is clear that the virus can induce mosaic-like symptoms on the tobacco leaves and in the Solanaceous family members.