Molecular Plant Pathology – Pathogen Profiles

Tobacco mosaic virus, not just a single component virus anymore

Elisabeth Knapp and Dennis J. Lewandowski
Department of Plant Pathology, University of Florida, Citrus Research and Education Center, Lake Alfred, FL 33850, USA

Taxonomy:Tobacco mosaic virus (TMV) is the type species of the Tobamovirus genus and a member of the alphavirus-like supergroup. Historically, many tobamoviruses are incorrectly called strains of TMV, although they can differ considerably in sequence similarities and host range from each other and from TMV.
Physical properties:TMV virions are 300 x 18 nm rods with a central hollow cavity and are composed of 95% capsid protein (CP), and 5% RNA. Each CP subunit interacts with 3-nts in a helical arrangement around the RNA. Virions are stable for decades; infectivity in sap survives heating to 90°C.
Host range:The natural host range of TMV is limited; however, a broad range of weed and crop species, mostly Solanaceae that includes tobacco, pepper and tomato can be infected experimentally [Holmes, F.O. (1946) A comparison of the experimental host ranges of tobacco etch and tobacco mosaic viruses. Phytopathology 36, 643-657]. TMV distribution is worldwide. No biological vectors are known.