Characterization of Two Novel Viruses Within a Complex Virome from Flowering Ginger in Hawaii.

Flowering ginger () is economically and culturally important in Hawaii. In the past decade, a slow decline syndrome has impacted the production of this crop in the state. RNA sequencing analyses and virus indexing surveys were done on samples collected from four of the Hawaiian Islands. Viral sequences corresponding to six viruses were recovered from transcriptomic data from samples with virus-like symptoms. Canna yellow mottle virus (CaYMV, genus ) and two novel viruses, Alpinia vein clearing virus (ApVCV, genus ) and Alpinia vein streaking virus (ApVSV, genus ), were found at a moderate incidence in diseased plants. Conversely, three other viruses, including the two potyviruses, banana bract mosaic virus and bean common mosaic virus, and a badnavirus, banana streak GF virus, were also found but at a low incidence. Virus detection in potential insect vectors and transmission assays identified the mealybug as a vector of CaYMV and ApVCV, whereas the aphid was identified as a vector of the novel ApVSV. Both and are common pests of flowering ginger in Hawaii. Transmission of ApVSV was achieved using colonies either established in the laboratory or naturally feeding on infected plants, although no transmission was obtained using viruliferous aphids originally reared on taro (). Our study provides insights into the potential association between viral infections and the observed decline symptoms of flowering ginger in Hawaii. However, more definitive studies are needed to link single or mixed viral infections with decline symptoms.