Tymoviridae are monopartite single-stranded positive sense RNA

RNA

Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....

 plant viruses, belonging to group IV of the Baltimore classification of viruses. The Tymoviridae are a relatively new family

Family

In human context, a family is a group of people affiliated by consanguinity, affinity, or co-residence. In most societies it is the principal institution for the socialization of children...

, only approved in 2002.

Virology

The virons are non-enveloped and isometric

Isometric

The term isometric comes from the Greek for "having equal measurement".isometric may mean:* Isometric projection , a method for the visual representation of three-dimensional objects in two dimensions; a form of orthographic projection, or more specifically, an axonometric projection.* Isometry and...

 with a diameter of around 30 nm, with an icosahedral structure and a triangulation number (T) = 3.

The linear genome

Genome

In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....

 is between of 6-7.5 kilobases in length and encodes one large open reading frame

Open reading frame

In molecular genetics, an open reading frame is a DNA sequence that does not contain a stop codon in a given reading frame.Normally, inserts which interrupt the reading frame of a subsequent region after the start codon cause frameshift mutation of the sequence and dislocate the sequences for stop...

. It is capped at the 5’ terminus. The 3’ terminus may have a tRNA-like structure or a polyA tract, depending upon the species. The genome is relatively cytosine

Cytosine

Cytosine is one of the four main bases found in DNA and RNA, along with adenine, guanine, and thymine . It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attached . The nucleoside of cytosine is cytidine...

 rich.

Taxonomy

The largest of three genera

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 is Tymovirus with 25 species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

, whereas the other genera, Marafivirus and Maculavirus have 5 and 1 species respectively.

The Tymoviridae family includes the following genera:

• Genus Tymovirus; type species: Turnip yellow mosaic virus
  Turnip yellow mosaic virus
  Turnip yellow mosaic virus is a tymovirus of the family Tymoviridae. These viruses infect dicotyledons while few of them attack monocotyledons also. They cause bright yellow mosaic disease showing vein clearing & molting of plant tissues.-External links:...
  
  
  • Asclepias asymptomatic virus
• Genus Marafivirus; type species: Maize rayado fino virus
• Genus Maculavirus
  • Bombyx mori Macula-like virus
  • Grapevine fleck virus (type species)

Unclassified viruses

• Fig fleck-associated virus
• Olive latent virus 3