What is tobacco mosaic virus, and what type of pathogen is it?

Sourav PanNovember 12, 2024

Answered

Tobacco mosaic virus (TMV) is a well-known plant pathogen classified as a virus, specifically a single-stranded RNA virus. It primarily infects tobacco plants and other members of the Solanaceae family, including tomatoes, peppers, and cucumbers.

Characteristics of Tobacco Mosaic Virus (TMV)

• Structure: TMV has a rod-like shape, measuring approximately 300 nanometers in length and 18 nanometers in diameter. It consists of a central core of single-stranded RNA surrounded by a protein coat (capsid) made up of about 2,130 identical protein subunits. This structure allows the virus to maintain stability and facilitate infection .
• Transmission: TMV can be transmitted through mechanical means, such as when infected sap comes into contact with healthy plants. It can also spread via vectors like aphids. Once inside a plant cell, the virus replicates and spreads to adjacent cells, causing systemic infection without killing the host cell .

Symptoms of Infection

Infected plants exhibit characteristic symptoms, including:

• Mosaic Patterns: Leaves show mottled discoloration, with light and dark green areas that give a “mosaic” appearance.
• Stunting: Growth may be stunted, particularly if infection occurs early in the growing season.
• Leaf Malformation: Leaves may become distorted or exhibit yellow streaking.

Historical Significance

TMV was the first virus to be discovered and studied extensively. Its identification laid the groundwork for modern virology. The discovery process involved key figures such as Adolf Mayer, Dmitri Ivanovsky, and Martinus Beijerinck, who contributed to understanding its infectious nature