A cilevirus infects ornamental hibiscus in Hawaii

The complete nucleotide sequence of a virus infecting ornamental hibiscus (Hibiscus sp.) in Hawaii with symptoms of green ringspots on senescing leaves was determined from double-stranded RNA isolated from symptomatic tissue. Excluding polyadenylated regions at the 3' termini, the bipartite RNA genome was 8748 and 5019 nt in length for RNA1 and RNA2, respectively. The genome organization was typical of a cilevirus: RNA1 encoded a large replication-associated protein with methyltransferase, protease, helicase and RNA-dependent RNA polymerase domains as well as a 29-kDa protein of unknown function. RNA2 possessed five open reading frames that potentially encoded proteins with molecular masses of 15, 7, 62, 32, and 24 kDa. The 32-kDa protein is homologous to 3A movement proteins of RNA viruses; the other proteins are of unknown function. A proteome comparison revealed that this virus was 92 % identical to citrus leprosis virus cytoplasmic type 2 (CiLV-C2), a recently characterized cilevirus infecting citrus with leprosis-like symptoms in Colombia. The high sequence similarity suggests that the virus described in this study could be a strain of CiLV-C2, but since the new genus Cilevirus does not have species demarcation criteria established at present, the classification of this virus infecting hibiscus is open to interpretation. This study represents the first documented case of a cilevirus established in the United States and provides insight into the diversity within the genus Cilevirus.