Bromoviridae

Family of viruses

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Bromoviridae
Kingdom:
Phylum:
Class:
Order:	Martellivirales
Family:	'Bromoviridae'

Bromoviridae is a family of viruses in the order Martellivirales. Members of this family are known to infect plants, causing a variety of plant diseases that can lead to significant agricultural losses. The family includes several genera, such as Alfamovirus, Anulavirus, Bromovirus, Cucumovirus, Ilarvirus, and Oleavirus.

Structure

Viruses in the Bromoviridae family are characterized by their non-enveloped, icosahedral capsids. The capsid is composed of a single type of protein and encapsidates the viral RNA genome. The genome is segmented and consists of three single-stranded, positive-sense RNA molecules. These segments are typically designated as RNA1, RNA2, and RNA3, with some genera also having a subgenomic RNA4.

Genome

The genome of Bromoviridae viruses is multipartite, meaning it is divided into several segments. Each segment is encapsidated separately. The RNA1 and RNA2 segments encode proteins involved in viral replication, while RNA3 encodes movement proteins and coat proteins necessary for cell-to-cell movement and encapsidation, respectively.

Replication

Replication of Bromoviridae viruses occurs in the cytoplasm of the host cell. The replication process begins with the translation of the viral RNA into proteins, followed by the synthesis of complementary RNA strands. The viral RNA-dependent RNA polymerase, encoded by RNA1, is responsible for replicating the viral genome. The movement proteins facilitate the spread of the virus from cell to cell within the host plant.

Transmission

Bromoviridae viruses are primarily transmitted through mechanical means, such as contact between plants or through human agricultural practices. Some members of the family can also be transmitted by insect vectors, such as aphids, in a non-persistent manner.

Economic Impact

Viruses in the Bromoviridae family can cause significant damage to crops, leading to reduced yields and economic losses. For example, Cucumber mosaic virus (CMV), a member of the Cucumovirus genus, is one of the most widespread plant viruses and affects a wide range of host plants, including important agricultural crops like cucumbers, tomatoes, and peppers.

Also see

• Plant virus
• Virus classification
• RNA virus
• Viral replication