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First Report of Tuberose mild mottle virus Infecting Tuberose (Polianthes tuberosa) in the United States

Dey, K. K., Melzer, M. J., Li, C., Sun, X., Adkins, S.
Plant disease 2018 v.102 no.2 pp. 461
Polianthes tuberosa, RNA, Tuberose mild mottle virus, bulbs, clones, container-grown plants, enzyme-linked immunosorbent assay, genetic databases, leaves, monoclonal antibodies, ornamental plants, plant diseases and disorders, plant industry, plant viruses, reverse transcriptase polymerase chain reaction, reverse transcription, viruses, China, Florida, India, Maryland, Mexico, New Zealand, Taiwan
Tuberose (Polianthes tuberosa L.) is a bulbous ornamental plant in the family Agavaceae native to Mexico. In September 2016, five P. tuberosa potted plants, originally from Miami, Florida, were received at the Division of Plant Industry in Gainesville, Florida. The leaves of the plants showed mild mottle and mosaic symptoms. Similar symptoms have been described from tuberose plants in New Zealand, China, Taiwan, and India and were identified as a viral disease caused by Tuberose mild mottle virus (TuMMoV; family Potyviridae, genus Potyvirus) (Lin et al. 2004; Kulshrestha et al. 2005). Initial serological testing for the presence of a potyvirus using broad-spectrum lateral flow immunoassays and antigen-coated plate ELISA (Agdia, Elkhart, IN), both of which are based on a monoclonal antibody (PTY 1), yielded positive results. To further identify the possible potyvirus, total RNA was extracted using an RNeasy Plant Mini kit (Qiagen, Valencia, CA) from one symptomatic leaf, and reverse-transcription (RT) PCR was performed using the degenerate potyvirus forward primers, Sprimer (5′- GGNAAYAAYAGYGGNCARCC-3′) (Chen et al. 2001) and CpUP (5′-TGAGGATCCTGGTGYATHGARAAYGG-3′) (van der Vlugt et al. 1999), with the reverse primers M4T (5′-GTTTTCCCAGTCACGAC[T]₁₅-3′) (Chen et al. 2001) or CpUP, which target the 3′-terminal region of most potyviruses. No amplification was observed for the Sprimer and M4T primer combination, but CpUP and M4T produced an amplicon of the expected size (∼700 bp). This product was cloned using the pGEM-T Easy II system (Promega, Madison, WI), and two clones were sequenced in both directions (GenBank accession no. MF326648). A BLASTN search against the GenBank database indicated the cloned sequences had 97% identity with TuMMoV (GenBank accession no. AY833736.1). The identification of TuMMoV was further confirmed by USDA-APHIS-PPQ-CPHST at Beltsville, Maryland, by two separate conventional RT-PCR assays and subsequent sequencing. TuMMoV-specific primers (TuMMoV-Fl, 5′- CGGGACTTCACCAAACATAAAC-3′; TuMMoV-R, 5′- CCACGAGGGAACACAGATAAA-3′; amplicon size, 470 bp) were subsequently designed and used in positive detection from two additional tuberose samples. To the best of our knowledge, this is the first report of TuMMoV in the United States. Because commercial cultivation of tuberose is from bulbs, movement of TuMMoV-infected bulbs may lead to further dissemination of this virus.