Investigation on Persimmon cryptic virus infection in persimmon (Diospyros kaki L.) orchards in Samsun province

Persimmon (Diospyros kaki L.) is a subtropical fruit species that blooms late in the spring. Eight virus species have been identified on persimmon so far. Among these viruses, Persimmon cryptic virus (PeCV) is a member of the genus Deltapartitivirus in the family Partitiviridae. Its genome has double-stranded RNA (dsRNA) with two segmented structures (RNA-1 and RNA-2). Since a commercial antiserum of PeCV is not available, molecular methods are used for its diagnosis. In this study, the possibility of applying dsRNA isolation method and the use of reverse transcription-polymerase chain reaction (RT-PCR) in the identification of PeCV were investigated. Fourteen asymptomatic and fourteen symptomatic leaf samples were taken from two persimmon orchards in Carsamba district of Samsun province in 2021. Viral dsRNAs were isolated from the collected leaf samples. Three different leaf weights (0.5 g, 1 g and 1.5 g) were used in dsRNA isolation. One-step RT-PCR has been applied in PeCV identification using a primer pair specific for its capsid protein region. In this study, an amplification product was only obtained from dsRNA samples of 1.5 g leaf weight. Out of four PeCV isolate, the important portion (994 bp) of capsid protein nucleotide sequences of one isolate (Çar-Eğri-13) was obtained. BLASTn analysis showed that the isolate Car-Eğri-13 had 99.69% nucleotide and amino acid identity with SSPI isolate (HE805114), which had 100% query coverage, identified in Italy. As a result, it was determined that PeCV was detectable in both symptomatic and asymptomatic leaf samples, and the amount of leaf tissue used was important for isolation of PeCV dsRNAs. Also, since this method is highly economical, it is recommended for testing the source of persimmon plant materials (rootstock, scion, and seedling) for certification purposes in the future.