Tobacco mosaic virus (TMV). 3D computer model showing the molecular structure of a tobacco mosaic virus particle (virion). This plant virus has an single stranded RNA (ribonucleic acid, red) genome. It was first identified over a hundred years ago in the tobacco plant (Nicotiana tabacum), but also infects many other plant species. Symptoms are mosaic patterns on the leaves (the so-called Leaf Mosaic Disease) which leads to severe crop loss. The virus is transmitted by seeds and contact between plants.