First report of Passiflora latent virus infecting persimmon (Diospyros Kaki) in Korea

Authors: CHO, IN-SOOK - Rural Development Administration - Korea; YANG, CHANG YEOL - Rural Development Administration - Korea; YOON, JU-YEON - Rural Development Administration - Korea; KWON, TAEK-RYOUN - Rural Development Administration - Korea; Hammond, John; LIM, HYOUN-SUB - Chungnam National University

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/13/2020
Publication Date: 2/26/2021
Citation: Cho, I., Yang, C., Yoon, J., Kwon, T., Hammond, J., Lim, H. 2021. First report of Passiflora latent virus infecting persimmon (Diospyros Kaki) in Korea. Plant Disease. 105(4):1236. https://doi.org/10.1094/PDIS-07-20-1502-PDN.
DOI: https://doi.org/10.1094/PDIS-07-20-1502-PDN

Interpretive Summary: Virus infections are common in vegetatively-propagated crops, and multiple viruses may accumulate during the lifetime of the crop. Occurrence of abnormal symptoms may indicate the presence of a new virus or virus combination, and identification and elimination of such additional viruses is necessary to maintain the productivity of the crop. Scientists in Korea noticed symptoms of foliar mosaic, leaf curling, and necrosis in persimmon trees in Gyeongsang Province, Korea; working with an ARS scientist in Beltsville, MD, they used molecular tests to identify the presence of Passiflora latent virus, an aphid-transmitted virus previously known only in Passiflora species, and not previously found in Korea. The infection was confirmed in two of 21 symptomatic trees, which were removed and destroyed to prevent possible infection of cultivated passion fruit vines in Korea. Identification of the virus in Korea will alert quarantine and regulatory agencies to the potential of the virus to infect persimmon as well as Passiflora species in Korea or other countries, while destruction of the infected trees minimizes the potential for transmission to additional plants of persimmon or to Passiflora species.

Technical Abstract: Passiflora latent virus (Passiflora latent virus; PLV), a member of the genus Carlavirus in the family Betaflexiviridae has been reported in Passiflora species in Australia, Germany, Israel, the United States and New Zealand (Tang et al., 2008). In 2019, leaves showing a virus-like disease with mosaic, curling and necrosis were collected from persimmon (Diospyros kaki Thunb.) orchards in Gyeongsang provinces, Korea. The pooled total RNA was extracted using RNeasy Plant Mini Kit (Qiagen, Germany) from these 21 trees leaves and subjected to high throughput sequencing; after pre-processing by mRNA purification and Ribo-Zero rRNA removal, a cDNA library was prepared using an Illumina TruSeq Stranded Total RNA kit and sequenced by the Illumina NovaSeq 6000 system (Macrogen Inc. Korea). De novo assembly of the 74,862,810 reads was performed by Trinity software (r20140717) assembled sequence data with BLASTN searches against the NCBI viral genome database of the initially assembled 213,476 contigs. From the assembled sequencing data, 12 contigs derived from PLV were identified, which has not previously been reported on persimmon either in Korea or elsewhere. The contigs ranging from 209 to 802 nt shared identities of 90.70 to 94.82% with PLV isolates, covering a total of 5169 nt (~61.6% of the full PLV genome). Two additional viruses were also detected from the samples: persimmon cryptic virus (PeCV) and persimmon virus A (PeVA). To confirm the presence of PLV, reverse transcription PCR was performed using virus-specific primer pairs PLV-F/R (5’-ACACAAAACTGCGTGTTGGA-3’/5’-CAAGACCCACCTACCTCAGTGTG-3’), designed based on the contig sequence. PCR products of the expected 571 bp were obtained from two samples and sequenced. The sequence (GenBank LC556232) showed 93.87% identity with the corresponding polymerase sequence of PLV-Rehovot isolate from passion fruit in Israel (MH379331). The two PLV positive samples showing leaf necrosis were co-infected with PeVA identified by RT-PCR with the previous reported primers PeVAfor and PeVArev (Morell et al., 2014). Infected persimmon trees were removed and destroyed because they might pose a threat to the cultivation of passion fruits in Korea. The degree of PLV foliar symptoms on passionfruit has been reported to vary through the year (Spiegel et al., 2007), but as the infected trees were destroyed, seasonal symptom variation on persimmon was not recorded. To our knowledge, this is the first report of PLV infecting persimmon in Korea, or indeed worldwide. A further survey is needed to understand the effect of PLV on persimmon and Passiflora species.