New viruses of Prunus
A new Luteovirus, tentatively called Nectarine stem pitting-associated virus (NSPaV), has been detected using metagenomic analysis in nectarine trees showing symptoms of stunting in a propagation block in California, US. These 5-year old trees had been propagated from scions of 3 nectarine cultivars imported from France and grafted onto peach rootstock (‘Nemaguard’). No foliar symptoms could be detected but extensive stem-pitting was observed under the bark above the graft union. Further studies are needed to verify the role of NSPaV in this stem-pitting disease of nectarine (Bag et al., 2015).
Two new betaflexiviruses, tentatively called Apricot vein clearing-associated virus (AVCaV) and Caucasus prunus virus (CPrV) have been detected using deep-sequencing analysis in apricot (Prunus armeniaca). AVCaV was detected in one apricot tree showing vein clearing symptoms in Southern Italy. As AVCaV was detected in mixed infection with Plum bark necrosis stem pitting-associated virus, further studies are needed to verify the possible role of AVCaV in the observed symptomatology (Elbeaino et al., 2014). In subsequent studies, AVCaV was detected in 2 Japanese plum trees (P. salicina) from a French germplasm collection and CPrV was detected in 1 almond tree (P. amygdalus) from Azerbaijan. It is also proposed that both AVCaV and CPrV belong to a new genus for which the name Prunevirus is proposed (Marais et al., 2015).
Bag S, Al Rwahnih M, Li A, Gonzalez A, Rowhani A, Uyemoto JK, Sudarshana MR (2015) Detection of a new Luteovirus in imported nectarine trees: a case study to propose adoption of metagenomics in post-entry quarantine. Phytopathology 105(6), 840-846.
Elbeaino T, Giampetruzzi A, De Stradis A, Digiaro M (2014) Deep-sequencing analysis of an apricot tree with vein clearing symptoms reveals the presence of a novel betaflexivirus. Virus Research 181, 1-5.
Marais A, Faure C, Mustafayev E, Candresse T (2015) Characterization of new isolates of Apricot vein clearing-associated virus and of a new Prunus-infecting virus: evidence for recombination as a driving force in Betaflexiviridae evolution. PLOS ONE 10(6), http://dx.doi.org/10.1371/journal.pone.0129469