TMVs

TMVs, commonly referred to as tobacco mosaic viruses, designate a group of plant-infecting viruses in the genus Tobamovirus within the family Virgaviridae. They are among the most studied plant viruses and have long served as model systems in virology and plant biology. TMVs are rigid, rod-shaped, non-enveloped particles that can be observed by electron microscopy. The virion length is typically about 300 nanometers with a diameter around 18 nanometers. The genome is a positive-sense single-stranded RNA of about 6.4 kilobases, encoding several proteins including a replication-associated protein, a movement protein, and a coat protein. The genome organization and high stability of TMV particles contribute to their persistence in the environment and their ease of study in laboratory settings.

Hosts and transmission are primarily plants in the family Solanaceae, among others. TMVs spread mainly through mechanical contact, contaminated tools, hands, or damaged tissue on plants. The diseases produced are commonly characterized by mosaic or mottling of leaves, leaf curling, and stunting, with potential reductions in yield and quality. Transmission by insect vectors is not typical for TMVs, though other tobamoviruses may share similar transmission routes. Control measures emphasize sanitation, removal of infected material, use of virus-free planting material, resistant cultivars where available, and careful handling of plants and tools to prevent mechanical transfer.

Historically, TMV was the first virus to be crystallized, a milestone achieved by Wendell Stanley in 1935 that helped establish viruses as chemical entities rather than cellular life forms. In modern science, TMV particles and coat proteins have become useful scaffolds in nanotechnology and materials science, leveraging their uniform size and predictable assembly. TMVs may also be used as a generic term for related tobamoviruses in various contexts.