Betacaulimoviruses

Betacaulimoviruses are a genus of viruses in the order Tubulavirales and the family Alphaflexiviridae. These viruses infect plants and are characterized by their filamentous virions and positive-sense single-stranded RNA genomes. The name "Betacaulimovirus" is derived from "beta" referring to its phylogenetic placement within the Alphaflexiviridae family, and "caulimovirus" referencing their structural and genomic similarities to caulimoviruses, although they are distinct viruses infecting different hosts.

The virions of Betacaulimoviruses are typically flexuous rods measuring approximately 650-800 nanometers in length and 7-8 nanometers in diameter. Their genomes consist of a single molecule of RNA, which is generally around 8-9 kilobases in size. The genome encodes several proteins, including a replicase, movement protein, coat protein, and potentially other smaller proteins involved in replication and assembly.

Betacaulimoviruses are transmitted by arthropod vectors, most commonly aphids, in a persistent manner. The viruses replicate within the plant host and move through the phloem tissue, causing a range of symptoms that can include mosaic patterns, leaf curling, stunting, and reduced yield. Different species within the genus infect various plant families, including Brassicaceae, Cucurbitaceae, and Solanaceae. Identification and characterization of Betacaulimoviruses often rely on a combination of biological assays, electron microscopy, and molecular techniques such as RT-PCR and sequencing. Control strategies focus on managing insect vectors and using resistant plant varieties where available.