The tobacco mosaic virus (TMV) is a species with a single strand of RNA in the Tobamovirus genus. Although numerous types of plants can become infected, the most common are members of the Solanaceae family including tobacco. Tobacco mosaic virus generally spreads between plants through wounds obtained from tools including hoes and pruning shears, clothing and contaminated hands.
TMV is found in extremely high concentrations within many plant cells. When handling your plants, some of the outer cells and extremely small leaf hairs sustain damage. The sap then leaks onto your clothing, tools and hands. The tobacco mosaic virus is also carried on the seed coats of infected plant seeds. When a plant is infected at a young age, there is a good chance the seed coat is contaminated during harvest.
As the seeds begin germinating, TMV often enters the seedlings using tiny cuts resulting from handling and transplanting or through the process of germination and emergence. Once the tobacco mosaic virus has entered your plant, the RNA or genetic code is released. Your plant confuses the virus for natural RNA, resulting in the production of viral proteins.
TMV is then able to spread to the surrounding cells by using microscopic channels located in the walls. Eventually, the tobacco mosaic virus enters the plant’s translocation systems of phloem and xylem, enabling the virus to spread throughout your entire plant.
What are the Two Major Components of the Tobacco Mosaic Virus?
The first key component of the tobacco mosaic virus is an RNA helix with a single strand and an 80 Å diameter called nucleic acid. The second is the capsid or protein coat consisting of approximately 2130 capsomers. Everything is packed close together in a helical pattern.
Tobacco Mosaic Virus Symptoms
There are variations in TMV symptoms depending on environmental conditions and plant species. Symptoms are frequently brought out by environmental conditions or hidden by other conditions. Certain symptoms are the result of higher temperatures, growth regulators, mineral excesses or deficiencies, insect feedings and herbicides.
You will be unable to diagnose TMV through the symptoms alone. The symptoms of the tobacco mosaic virus include stunted growth, mosaic patterns on the leaves in varying shades of green and yellow, malformed areas on growing plants and yellow streaks, spot or veins on the leaves. The most common TMV symptoms include:
- Mosaic patterns of dark and light green or yellow and green
- Malformed leaves
- Yellow spots or streaks on the leaves
- Yellowing veins
- Small, curled or wrinkled leaves
- Infected fruit with a mottled appearance and raised warts
- Decreased yields and stunted growth
How to Get Rid of Tobacco Mosaic Virus
There are currently no natural or chemical cures for TMV, but you can take these measures to prevent the tobacco mosaic virus:
- Purchase virus-free plants
- Remove all weeds
- Remove all debris from within greenhouse structures
- Discard infected plants
- Disinfect tools and any other structures if growing indoors
- Grow plants from seed
- Thoroughly wash your hands after handling infected plants
Who Discovered the Tobacco Mosaic Virus?
The tobacco mosaic virus was originally discovered in 1892 by Ivanoski. He proved that even after the infected leaves were filtered, the infection remained. The retention of bacteria through filtration resulted in the discovery of filterable pathogens. In 1889, a second scientist named Martinus Beijerinck made the discovery the tobacco mosaic virus resulted from a pathogen.
This pathogen was able to multiply and reproduce in the plant’s host cells. He called the pathogen a virus to differentiate the tobacco mosaic virus from other types of diseases caused by bacteria.
What Plants Can be Infected with TMV?
The tobacco mosaic virus is known for infecting nine different plant families. There is a minimum of 125 individual Solanaceae species susceptible including peppers, tomatoes, cucumbers and tobacco. The host range of tobacco mosaic virus is extremely wide, affecting many different vegetables, ornamentals, weeds and crops including marijuana, lettuce, petunias, horsenettle, beans, beets, jimson weed, potatoes and roses.