Molecular detection and characterization of cherry virus a in Prunus species in Serbia

Abstract

Stone fruits (plums, apricots, peaches, and cherries) are economically important species for Serbian agriculture. These fruits harbor numerous viruses that can decrease yield and fruit quality. Cherry virus A (CVA), a member of the genus Capillovirus, was discovered during the cloning of the little cherry agent. CVA is widely distributed in more than 10 countries in sweet and sour cherries, but also in other Prunus hosts. So far, CVA has been confirmed in Serbia in sweet and sour cherries. A total of 106 leaf samples from 31 orchards in 22 locations were collected and examined to determine the prevalence of CVA in stone fruit orchards in Serbia. Great majority of leaf samples were symptomless, but some exhibited symptoms of chlorotic mottling, necrotic spots, and vein necrosis. Samples were tested by reverse transcription polymerase chain reaction (RT-PCR) using a virus-specific primer pair CVA-fw1/CVA-rev1 that amplify a fragment of the movement protein (MP) gene. PCR products were analyzed by electrophoresis in 1.5% agarose gel and stained with ethidium-bromide. To further access diversity of the detected isolates, we sequenced a partial MP of four detected isolates. The results of the RT-PCR revealed that 13 samples (12.3%) were infected with CVA. An expected 302 bp fragment was obtained in eight tested samples of sweet cherry, three apricot, and two plums. No positive amplification was evidenced in analyzed sour cherry and peach samples. CVA was detected in both asymptomatic and symptomatic samples. In all positive samples with symptoms, mixed infection with other viruses (prune dwarf virus, little cherry virus 1, and cherry green ring mottle virus) was detected. It is still unclear whether CVA is associated with any of the observed symptoms. The nucleotide sequences of the isolates showed 89.7–99.6% identity. To the best of our knowledge this is the first report of cherry virus A in apricots and plums in Serbia.