An assemblage of closteroviruses infects Hawaiian ti (Cordyline fruticosa L.)

The ti plant (Cordyline fruticosa L.) is culturally important throughout most of Polynesia and has considerable economic importance in Hawai'i where the foliage is commonly used in cultural ceremonies as well as food and ornamental industries. In Hawai'i, ringspot symptoms were recently observed on leaves of the common green variety of ti growing in Kahalu'u on the island of O'ahu, and Wailuku and Hana on the island of Maui. High molecular weight double-stranded (ds)RNAs were isolated from the leaves of symptomatic plants as well as plants without symptoms. A cDNA library derived from the dsRNAs present in symptomatic plants was generated and sequenced. These sequences indicated at least four distinct clostero-like viruses were present in the plants, and phylogenetic analyses suggested they were most closely related to Little cherry virus 1, an unassigned member of the family Closteroviridae. The 16,883 nucleotide genome of one of these viruses was determined and predicted to contain ten open reading frames with an organization typical of closteroviruses. Reverse-transcription PCR revealed this virus was present in both symptomatic and asymptomatic ti plants, making it unlikely to be responsible for the observed ringspot symptoms. We propose the name Cordyline virus 1 (CoV-1) for this virus and include it as a new, unassigned member of the family Closteroviridae.