Closterovirinae

Closterovirinae is a subfamily of viruses within the family Closteroviridae. Viruses in this subfamily are characterized by their long, filamentous, and flexuous virions. They infect plants and are known to cause a range of economically important diseases. The genome of Closterovirinae viruses consists of a single-stranded, positive-sense RNA molecule. A notable feature of their genome is its large size, typically around 15 to 20 kilobases, and the presence of a unique gene encoding a heat shock protein 70 homolog.

The replication cycle of Closterovirinae viruses occurs entirely within the cytoplasm of host plant cells. They are transmitted by insect vectors, primarily aphids, which acquire the virus by feeding on an infected plant and then transmit it to a healthy plant during subsequent feeding. Diseases caused by these viruses can include yellowing, stunting, leaf curling, and reduced fruit quality, leading to significant crop losses in citrus, grapevine, and other agricultural systems.

The subfamily Closterovirinae currently comprises several genera, including *Ampelovirus*, *Closterovirus*, *Cilevirus*, and *Velarivirus*. Each genus contains viruses that infect specific plant hosts and cause distinct disease symptoms. Research into Closterovirinae viruses is crucial for developing effective strategies for disease management and ensuring the sustainability of affected agricultural industries. Diagnostic methods and the development of resistant plant varieties are ongoing areas of study.

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