First report of dasheen mosaic virus infecting calla lilies in South Korea

Authors: CHO, IN-SOOK - Rural Development Administration - Korea; CHUNG, BONG-NAM - Rural Development Administration - Korea; CHOI, S.N. - Rural Development Administration - Korea; Hammond, John; LIM, HYOUN-SUB - Chungnam National University

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/6/2023
Publication Date: 6/9/2023
Citation: Cho, I., Chung, B., Choi, S., Hammond, J., Lim, H. 2023. First report of dasheen mosaic virus infecting calla lilies in South Korea. Plant Disease. https://doi.org/10.1094/PDIS-11-22-2647-PDN.
DOI: https://doi.org/10.1094/PDIS-11-22-2647-PDN

Interpretive Summary: Virus infections cause losses of yield and quality in many crops, and are especially important in vegetatively propagated crops, as the viruses are almost uniformly transmitted from infected other plants. Further viruses may be introduced into the crop by mechanical means, or transmission by vectors such as aphids. An ARS scientist collaborated with Korean scientists to identify the viruses present in calla lilies in Korea. In addition to two viruses previously identified in this crop in Korea, dasheen mosaic virus was detected in calla lilies for the first time in Korea. When additional calla lily samples from various regions were tested, more than 10% were found to be infected by dasheen mosaic virus. Identification of an additional virus infecting calla lilies in Korea will aid management of the crop to improve the quality and productivity of this ornamental grown both as a pot plant and for cut flowers.

Technical Abstract: In April 2022, leaves showing virus-like symptoms including mosaic, feathery chlorotic mottle and distortions were observed on calla lilies (Zantedeschia sp.) growing in a greenhouse in Jeolla province, South Korea. Leaf samples from nine symptomatic plants from the same greenhouse were collected and tested for Zantedeschia mosaic virus (ZaMV), Zantedeschia mild mosaic virus (ZaMMV) and Dasheen mosaic virus (DaMV) by reverse transcription-polymerase chain reaction (RT-PCR) with specific primers, ZaMV-F/R, ZaMMV-F/R (5’-GACGATCAGCAACAGCAGCAACAGCAGAAG-3’/5’-CTGCAAGGCTGAGATCCCGAGTAGCGAGTG-3’) and DsMV-CPF/CPR(5’-GCTGACGATACAGTTGATGCAGGAAATAAT-3’/5’-CTGTGGAGGAGACACACCGAGCAATGTATG-3’) (based on calla lily isolates AY626825, and AJ298033 respectively), respectively. In previous surveys, ZaMV and ZaMMV were detected in calla lily fields in South Korea. Of 9 symptomatic samples, 8 were positive for ZaMV and ZaMMV but no PCR product was obtained from the ninth sample, which showed a yellow feather-like pattern . To identify the causal virus, total RNA from a leaf sample of the symptomatic calla lily was extracted using an RNeasy Plant Mini Kit and analyzed by high-throughput sequencing. Ribosomal RNA was removed and a cDNA library was prepared using an Illumina TruSeq Stranded Total RNA LT Sample Prep Kit (Plants) and sequenced on an Illumina NovaSeq 6000 system, yielding 150 nt paired end reads. De novo assembly of the 88,171,036 reads was performed using Trinity software (r20140717) while the 113,140 initially assembled contigs were screened against the NCBI viral genome database using BLASTN. One contig of 10,007 bp (GenBank LC723667) shared 79.89 to 87.08% nucleotide (nt) identities with Dasheen mosaic virus (DsMV) isolates in GenBank. No contigs representing other plant viruses were identified. To confirm the presence of DsMV, reverse transcription-polymerase chain reaction (RT-PCR) was performed using virus-specific primers DsMV-F/R (5’-GATGTCAACGCTGGCACCAGT-3’/5’-CAACCTAGTAGTAACGTTGGAGA-3’), designed based on the contig sequence. PCR products of the expected 600 bp were obtained from the symptomatic plant. Amplicons were cloned into the pGEM-T Easy Vector, and two independent clones were bidirectionally sequenced (BIONEER, Korea) and deposited in GenBank. The 600 bp amplicon (acc. no. LC723766) showed 91.83% nt identity to a Chinese calla lily isolate of DsMV (AJ298033). DsMV, a member of the genus Potyvitus in the family Potyviridae, is one of the major viruses infecting taro in South Korea, showing mosaic and chlorotic feathering symptoms; however, there is no record in the literature of the identification of this virus in South Korea in other ornamental species including calla lily. To survey the sanitary status of other calla lilies, 95 samples were collected from other regions and subjected to RT-PCR detection for DsMV. Ten of these samples were positive with primers DsMV-F/R, but not with DsMV-CPF/CPR, likely due to the several mismatches to the contig sequence. To our knowledge, this is the first report of DsMV infecting calla lilies in South Korea. The virus is easily spread by vegetative propagation and by aphids. This study will help the management of viral diseases on calla lilies in South Korea.