Location: Crop Improvement and Protection ResearchTitle: First report of watermelon mosaic virus naturally infecting coriander (Coriandrum sativum) and causing a leaf mottling disease in California
|CESPEDES, M - University Of California|
|MELGAREIO, T - University Of California|
|RWAHNIH, M - University Of California|
|GILBERTSON, R - University Of California|
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/2022
Publication Date: 9/21/2022
Citation: Cespedes, M.K., Melgareio, T.A., Henry, P.M., Rwahnih, M.A., Gilbertson, R.L. 2022. First report of watermelon mosaic virus naturally infecting coriander (Coriandrum sativum) and causing a leaf mottling disease in California. Plant Disease. https://doi.org/10.1094/PDIS-05-22-1184-PDN.
Interpretive Summary: Watermelon mosaic virus (WMV) causes disease in a wide range of plant species, but to date has never been reported as causing disease in coriander (synonym: cilantro, Coriandrum sativum). In 2018, coriander plants with symptoms of light green mottling and crumpling were recovered from two gardens in Davis, CA. DNA-based assays indicated the suspected causal agent was a virus with high similarity to other, known strains of WMV. The virus was inoculated onto two different hosts, upon which typical WMV symptoms were observed. High-throughput sequencing confirmed the presence of WMV and no other plant viruses. These symptomatic tissues (containing only WMV) were used to inoculate coriander, melon, squash, and pumpkin, which all developed WMV symptoms. This is the first report of WMV causing disease of coriander.
Technical Abstract: Watermelon mosaic virus (WMV, genus Potyvirus, family Potyviridae) is a species of considerable economic importance to cucurbit crops worldwide. This virus has a wide host range that includes more than 170 plant species from 27 families. In 2018, leaves of coriander (Coriandrum sativum) plants in a student garden (C-SG) at UC Davis, and in a home garden in Davis, CA (C-Pet) showed symptoms of light green mottling and crumpling. Samples of symptomatic leaves from each location were weakly positive with the general Potyvirus immunostrip test (Agdia, Elkhart, IN). Reverse transcriptase PCR was conducted with Potyvirus degenerate primers, amplicons were gel-purified, and purified DNA was sequenced. Sequences recovered from C-SG and C-Pet revealed high percent identities with WMV sequences from the U.S. The virus was passaged through Chenopodium quinoa, Nicotiana benthamiana by mechanical inoculation. High-throughput sequencing was used on symptomatic tissue from N. benthamiana plants to confirm the presence of WMV and the absence of any other plant viruses. Sap from symptomatic N. benthamiana was then used to inoculate coriander, melon, pumpkin, and squash, which developed symptoms consistent with WMV infection. This is the first report of a mottle disease of coriander caused by WMV, which adds to the wide host range of WMV. Infected coriander plants are a potential inoculum source for cucurbits via several aphid vectors, and vice versa.