First Report of Orchid fleck virus in Lilyturf (Liriope spicata) in Australia

MEI, YONGYU; BEJERMAN, NICOLÁS; CREW, KARYN; MCCAFFREY, NICK; DIETZGEN RALF

PLANT DISEASE

AMER PHYTOPATHOLOGICAL SOC

Año: 2016

0191-2917

Liriope spicata (Asparagaceae) is an evergreen ornamental plant commonly referred to aslilyturf, creeping liriope, monkey grass, or creeping lilyturf, and is widely grown asgroundcover and for erosion control (Fantz 2008). In April 2015, lilyturf plants with brightyellow flecks on the leaves were observed in landscape plantings across the St. Luciacampus of the University of Queensland, Brisbane, Australia. These symptoms werereminiscent of those observed on leaves of orchid species infected by Orchid fleck virus(OFV) (Kubo et al. 2009). Symptomatic leaf samples were collected and analyzed in aJEM-1400 transmission electron microscope (JEOL Ltd., Tokyo, Japan). Leaf dips wereprepared by breaking up symptomatic tissue in 1% ammonium molybdate, pH 7.0negative stain and extracts were placed on nitrocellulose-coated copper grids. Digitalmicrographs were captured with an Orius digital camera (Gatan Inc., Pleasanton, CA).Typical nonenveloped, rhabdovirus-like, bacilliform particles measuring ∼45 × 95 nm wereobserved, similar to those of OFV from infected orchids (Kondo et al. 2006). Total RNA wasextracted from symptomatic tissue using an RNeasy Plant Mini Kit (Qiagen) and subjectedto RT-PCR using the Superscript III One Step RT-PCR System with Platinum Taq DNAPolymerase (Thermo Fisher) and OFV nucleoprotein (N) gene primers polydT/SP6 (5′-GATTTAGGTGACACTATAGTTTTTTTTTTTTTTTTT(A/G/C)-3′) and mN2(5′-TGCAGGAATATAGCCGACATGTT-3′) (Blanchfield et al. 2001). Agarose gelelectrophoresis showed a single amplicon of ∼800 bp, comparable to the OFV positivecontrol. DNA from both the lilyturf (DAF Plant Virus Collection Accession No. 5216) and acymbidium OFV control (Accession No. 703) amplicons were gel-purified and cloned intopGEM-T Easy vector (Promega, Madison, WI) and sequenced using dideoxynucleotidesequencing at the Australian Genome Research Facility (Brisbane, Australia). A GenBankBLASTx search of the lilyturf virus N gene sequence of 658 nt showed 100% match to theN protein sequence of an Australian OFV isolate (Genbank Accession No. AAK09392 ande-value 1e−143). The partial N gene nucleotide sequence of the lilyturf OFV isolate #5216was 99% identical to the cymbidium OFV isolate. Both sequences have been deposited inGenBank with Accession Nos. KT947974 and KT947975, respectively. Based on theobserved symptoms, particle morphology, N gene amplicon using OFV primers, and highsequence identity with other OFV sequences, we conclude that the lilyturf plants wereinfected with OFV. This is the first report of OFV infecting L. spicata. This alternative hostmay play a possible role in OFV spread to orchids or other ornamental species that arecolonized by its Brevipalpus sp. mite vector.