Characterization of tobacco ringspot virus and its nematode vector,Xiphinema rivesi, infecting highbush blueberry in Washington State

Authors: MITRA, ARUNABHA - University Of California; JARUGULA, SRIDHAR - Washington State University; AKINBADE, SEGUN - Washington State University; Handoo, Zafar; KANTOR, MIHAIL - Pennsylvania State University; Mowery, Joseph; NAIDU, RAYAPATI - Washington State University

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/31/2025
Publication Date: 12/16/2025
Citation: Mitra, A., Jarugula, S., Akinbade, S.A., Handoo, Z.A., Kantor, M., Mowery, J.D., Naidu, R.A. 2025. Characterization of tobacco ringspot virus and its nematode vector, Xiphinema rivesi, infecting highbush blueberry in Washington State. Plant Disease. https://doi.org/10.1094/PDIS-10-24-2236-RE.
DOI: https://doi.org/10.1094/PDIS-10-24-2236-RE

Interpretive Summary: Plant-parasitic nematodes are microscopic worms that feed on plants and cause an estimated ten billion dollars of crop losses each year in the United States and 100 billion dollars globally. In some situations, nematodes can transfer viruses to plants. In this study, the discovery of berries from virus-infected plants showing significant reduction in total soluble solids, juice pH, anthocyanins, and titratable acidity compared to berries from healthy plants is reported. Symptomatic plants tested positive for Tobacco Ringspot Virus (TSRV). TRSV transmission by soil-inhabiting dagger nematodes (Xiphinema rivesi) was demonstrated via plant assays. TRSV detected in isolated dagger nematodes further supported their virus carrying capability. The present study is the first report of TRSV infecting highbush blueberry in Washington State and confirms that a nematode carrier may be involved in the disease process. Therefore, this research will be used by scientists, diagnosticians, growers, action agencies, and extension agencies involved in nematode research and control.

Technical Abstract: Highbush blueberry (Vaccinium corymbosum L.) plants showing severe defoliation and stunting were observed in an organic blueberry farm in eastern Washington State. Affected plants showed a wide range of symptoms with overall decline within a few years. TRSV-infected blueberry plants produced small berries with uneven size and ripening compared to normal berries with uniform ripening produced by healthy plants. Berries from virus-infected plants showed significant reduction in total soluble solids, juice pH, anthocyanins, and titratable acidity compared to berries from healthy plants. In double antibody sandwich (DAS) ELISA, symptomatic plants tested positive for Tobacco ringspot virus (TRSV, genus Nepovirus, family Secoviridae). TRSV infection was confirmed by RT-PCR assays targeting RNA1-encoded Helicase (Hel) and RNA2-encoded Coat Protein (CP). With high-throughput and Sanger sequencing, the complete sequence of RNA1 and RNA2 genome segments was determined to be 7,512 nucleotides (nt) and 3,925 nt, respectively. In phylogenetic analyses, the RNA1 and RNA2 segments aligned, respectively, with corresponding sequences of TRSV isolates from South Korea and Iowa. TRSV transmission by soil-inhabiting dagger nematodes (Xiphinema rivesi) was demonstrated via in-field bait plant assays. TRSV detected in isolated dagger nematodes further supported their virus vectoring capability. The present study is the first report of TRSV infecting highbush blueberry in Washington State.