Blueberry mosaic associated ophiovirus
Blueberry mosaic associated ophiovirus | |
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Mosaic pattern on leaves of raspberry plant, also a characteristic of Blueberry mosaic associated ophiovirus | |
Virus classification | |
(unranked): | Virus |
Realm: | Riboviria |
Kingdom: | Orthornavirae |
Phylum: | Negarnaviricota
|
Class: | Milneviricetes |
Order: | Serpentovirales |
Family: | Aspiviridae |
Genus: | Ophiovirus
|
Species: | Blueberry mosaic associated ophiovirus
|
The Blueberry mosaic associated ophiovirus (B1MaV) is a
Symptoms
When a plant is initially infected with the virus the plant will often display a symptom-free period, meaning there is long latent period between viral infection and symptom appearance.[3] The virus can also become dormant in some areas of the plant and expressed in others, causing some leaves to display symptoms and others to be asymptomatic.
When a blueberry plant begins to show symptoms of infection by B1MaV a mild to severe mottle and mosaic patterns on foliage appears. The pattern is in the colors of yellow, yellow green, and pink. Usually symptoms appear on only a few leaves, but can appear on more of the plant in severe seasons.[2] The infection also causes late ripening of fruit, reduced yield of the crop, and poor quality of the berries, as the virus spreads throughout the plant and begins affecting cellular mechanisms.[3] The virus does not kill the plant, however, rather it just affects the quality and quantity of fruit produced by the plant.
Structure
The blueberry mosaic associated ophiovirus virion is described as a nonenveloped
Genome
The genome is a linear segmented genome that is 11,467 nucleotides long and is composed of three negative single strand RNA sequences.
The 5’ terminal sequences are not conserved between RNA transmissions, but all of the 5’ termini fold into conserved stem-loop structures. These structures are likely involved in packaging of the genomic RNAs into their capsid or in long-distance interactions for transcription and translation.[1] The 3’ terminal of all three RNAs are identical and conserved. The conserved nucleotide sequence is ‘AAUAUC’.[2]
Ophiovirdae have a G+C content is 32.3-39.8%.[8] The genome of Ophiovirdae is typically 11.3-12.5 kilobytes long.[6] These viral RNA sequences appear in higher concentrations in symptomatic leaves then in asymptomatic leaves of the same plant.[3]
Replication cycle
Entry into cell
Ophiovirdae travel from cell to cell in a plant via plasmodesmata and often alter the flexibility of the plasmodesmata by affecting proteins such as movement proteins of the virus. The movement proteins that the virus encodes in RNA 2, often effect cellular mechanisms for transport to distant tissues in the plant.[9] B1MaV has nuclear localization signals within its protein sequences.[6] These amino acid sequences tag the protein for import into the cell's nucleus via nuclear transport mechanisms of the cell.[10]
Replication and transcription
B1MaV is translated from mRNA which is complementary to the vRNAs of the virus genome.[10] Replication of ophioviruses as well as virion assembly is believed to occur in the cytoplasm.[11]
Modulation of host processes
There are several proteins produced by the viral mRNA in transcription and translation that affect the host cells processes, making a more suitable environment for viral replication and transcription. There is not much information known as to exactly what viral proteins interfere with the host cell processes.
One protein that is encoded on RNA 2 is the movement protein for B1MaV. This protein helps the virus travel between cells via plasmodesmata. It also is involved in suppression in post translational gene silencing of cellular genes, therefore preventing the silencing of some cellular genes causing consequent expression and the effects of these expressed genes.[3][9]
Tropism
The virus is transmissible via grafting, meaning that when an infected plant is joined with a noninfected plant to promote continued growth of the plant, the infected plant spreads the virus to the once noninfected plant.[3] Asymptomatic plants can serve as reservoirs for the pathogen that can in turn spread the disease to highly susceptible plants. The virus can further spread to new growing areas accidentally by plant nurseries since blueberries are reproduced asexually and asymptomatic blueberry plants may be used.[1] Ophiovirdae are also transmitted through the soil via fungi. This would allow B1MaV to survive in the spores of an infected root fungi leading to further spread.[1] Since the viral genome is three segmented negative RNA strands, there is the possibility for re-assortment of genetic segments between B1MaV and other segmented viruses infecting the same plant, leading to possible further transmission of the virus by other means.[7]
Associated diseases
Citrus psorosis virus
Lettuce ring necrosis virus
Lettuce ring necrosis is a viral infection that affects lettuce leaves, causing necrotic ring like patterns on the middle of leaves. The infected leaves often decay and make the whole plant unusable. As with B1MaV, the lettuce ring necrosis virus spreads via soil transmission through fungal
References
- ^ ISSN 0168-1702.
- ^ ISSN 0567-7572.
- ^ ISSN 1610-739X.
- ^ a b c "Aspiviridae", Wikipedia, 2019-10-04, retrieved 2019-11-27
- PMID 28635587.
- ^ a b c d "Aspiviridae - Aspiviridae - Negative-sense RNA Viruses". International Committee on Taxonomy of Viruses (ICTV). Archived from the original on January 15, 2019. Retrieved 2019-11-27.
- ^ ISSN 0168-1702.
- ISBN 978-0-387-95919-1
- ^ PMID 23602594.
- ^ a b c "Nuclear localization sequence", Wikipedia, 2019-09-19, retrieved 2019-11-27
- PMID 22921760.
- ^ PMID 25674593.
- ISSN 1573-8469.
- ISSN 1365-3059.