Onion yellow dwarf virus
{{Short description|Species of virus}}
{{Virusbox
| parent = Potyvirus
| species = Onion yellow dwarf virus
| image = 1635363-PPT.jpg
| image_caption = Symptoms of onion yellow dwarf virus in onions (Allium cepa L.)
}}
Onion yellow dwarf virus (OYDV) is a plant virus in the genus Potyvirus that has been identified worldwide and mainly infects species of Allium such as onion, garlic, and leek.{{cite journal |last1=Ward |first1=L. I. |last2=Perez-Egusquiza |first2=Z. |last3=Fletcher |first3=J. D. |last4=Clover |first4=G. R. G. |title=A survey of viral diseases of Allium crops in New Zealand |journal=Australasian Plant Pathology |date=2009 |volume=38 |issue=5 |pages=533 |doi=10.1071/AP09039|bibcode=2009AuPP...38..533W |s2cid=39328059 }}{{Cite journal|last1=PARRANO|first1=Leonardo|last2=AFUNIAN|first2=Mohammad|last3=PAGLIACCIA|first3=Deborah|last4=DOUHAN|first4=Greg|last5=VIDALAKIS|first5=Georgios|date=2012|title=Characterization of viruses associated with garlic plants propagated from different reproductive tissues from Italy and other geographic regions|url=https://www.jstor.org/stable/43872342|journal=Phytopathologia Mediterranea|volume=51|issue=3|pages=549–565|jstor=43872342|issn=0031-9465}}{{cite journal |last1=Abraham |first1=A. D. |last2=Kidanemariam |first2=D. B. |last3=Holton |first3=T. A. |title=Molecular identification, incidence and phylogenetic analysis of seven viruses infecting garlic in Ethiopia |journal=European Journal of Plant Pathology |date=15 May 2019 |volume=155 |issue=1 |pages=181–191 |doi=10.1007/s10658-019-01760-9|pmid=33304030 |pmc=7680954 |doi-access=free |bibcode=2019EJPP..155..181A }}{{cite journal |last1=Santosa |first1=Adyatma Irawan |last2=Ertunc |first2=Filiz |title=Identification, molecular detection and phylogenetic analysis of four viruses infecting Allium cepa in Ankara Province, Turkey |journal=Journal of Plant Diseases and Protection |date=19 June 2020 |volume=127 |issue=4 |pages=561–569 |doi=10.1007/s41348-020-00347-5|s2cid=225488130 }} The virus causes mild to severe leaf malformation, and bulb reduction up to sixty percent has been observed in garlic.{{Cite journal|last1=Lot|first1=Harve|last2=Chovelon|first2=Véronique|last3=Souche|first3=Sylvie|last4=Delecolle|first4=Brigitte|date=2007|title=Effects of Onion Yellow Dwarf and Leek Yellow Stripe Viruses on Symptomatology and Yield Loss of Three French Garlic Cultivars|journal=Plant Disease|language=en|volume=82|issue=12|pages=1381–1385|doi=10.1094/PDIS.1998.82.12.1381|pmid=30845474|issn=0191-2917|doi-access=}}
Genome
The full genome of OYDV is around 10,538 nucleotides long and encodes a polyprotein of 3,403 amino acids. Its P3 gene is longer than those of other known Potyviruses.{{Cite journal|last1=Chen|first1=J.|last2=Adams|first2=M. J.|last3=Zheng|first3=H.-Y.|last4=Chen|first4=J.-P.|date=2003-05-01|title=Sequence analysis demonstrates that Onion yellow dwarf virus isolates from China contain a P3 region much larger than other potyviruses|url=http://link.springer.com/10.1007/s00705-003-0020-1|journal=Archives of Virology|volume=148|issue=6|pages=1165–1173|doi=10.1007/s00705-003-0020-1|pmid=12756621|s2cid=10079689|issn=0304-8608}}
OYDV is the first potyvirus found which has natural deletion mutants lacking the N-terminal region of helper-component proteinase (HC-Pro). The mutant isolates are common. Garlic plants grown commercially are generally co-infected with both the normal and attenuated isolates.{{cite journal |last1=Takaki |first1=F. |last2=Sano |first2=T. |last3=Yamashita |first3=K. |title=The complete nucleotide sequence of attenuated onion yellow dwarf virus: a natural potyvirus deletion mutant lacking the N-terminal 92 amino acids of HC-Pro |journal=Archives of Virology |date=3 July 2006 |volume=151 |issue=7 |pages=1439–1445 |doi=10.1007/s00705-005-0716-5|pmid=16463124 |s2cid=35484265 }} RNA silencing suppressor activities in isolates, which lack the long stretch of the N-terminal amino acids (~ 100 residues) in their HC-Pro gene, are observed to be low.{{cite journal |last1=Kim |first1=Hangil |last2=Aoki |first2=Nana |last3=Takahashi |first3=Haruna |last4=Yoshida |first4=Naoto |last5=Shimura |first5=Hanako |last6=Masuta |first6=Chikara |title=Reduced RNA silencing suppressor activity of onion yellow dwarf virus HC-Pro with N-terminal deletion may be complemented in mixed infection with another potyvirus in garlic |journal=Journal of General Plant Pathology |date=14 May 2020 |volume=86 |issue=4 |pages=300–309 |doi=10.1007/s10327-020-00926-2|bibcode=2020JGPP...86..300K |s2cid=218624707 }}
Transmission
Isolates with complete HC-Pro sequences were non-persistently transmitted by aphids on their own, while the isolates with short HC-Pros (OYDV-S) were only aphid transmissible when they were co-infected with leek yellow stripe virus (LYSV), another potyvirus that mostly infects Allium spp. LYSV HC-Pro was assumed to interlink both LYSV and OYDV-S with the aphid stylet.{{cite journal |last1=Jayasinghe |first1=Wikum H. |last2=Kim |first2=Hangil |last3=Sasaki |first3=June |last4=Masuta |first4=Chikara |title=Aphid transmissibility of onion yellow dwarf virus isolates with an N-terminal truncated HC-Pro is aided by leek yellow stripe virus |journal=Journal of General Plant Pathology |date=7 March 2021 |volume=87 |issue=3 |pages=178–183 |doi=10.1007/s10327-021-00986-y|bibcode=2021JGPP...87..178J |s2cid=233782267 }} OYDV is not transmitted by dodder.{{cite journal |last1=Bos |first1=L. |title=Viruses and Virus Diseases of Allium Species |journal=Acta Horticulturae |year=1983 |issue=127 |pages=11–30 |doi=10.17660/ActaHortic.1983.127.1}}