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Poster: Diseases of Plants: New & Emerging Diseases


Molecular Detection of Ti ringspot associated virus, a novel emaravirus associated with ti ringspot disease of Cordyline fruticosa (L.) in Hawai’i
M. MELZER (1), A. Park (1) (1) University of Hawaii, U.S.A.

An emerging virus-like disease of ti plant (Cordyline fruticosa L.) is spreading quickly throughout the Hawaiian Islands. Foliar symptoms include chlorotic lesions constricted by secondary veins or circular ring-spots that can coalesce into amorphous lesions. Tissue samples were collected from various locations across Hawaii and RNA was extracted. Degenerate RT-PCR primers targeting the polymerase gene of known emaraviruses amplified a ~400 bp product from the RNA of symptomatic plants. The RT-PCR products were sequenced and found to be >97.5% identical, indicating they represent a single virus species, designated Ti ringspot associated virus (TiRaV). When translated into amino acid sequences, this virus was found to be 70% identical to Raspberry leaf blotch virus, 55% to European mountain ash ringspot-associated virus, 53% to Redbud yellow ringspot virus, 50% to Rose rosette virus, 49% to Fig mosaic virus (FMV), and 46% to Pigeon pea sterility mosaic virus. These sequences and the C. fruticosa large rubisco subunit sequence were used to create specific primers and probes for a multiplex RT-qPCR detection assay. This assay was able to reliably detect TiRaV in symptomatic samples collected from various locations across Hawaii, and did not react to asymptomatic samples or cross react with an isolate of FMV.