Complete Genome Sequences of Two Hydrangea Ringspot Virus Isolates from Japan

Hydrangea ringspot virus (HdRSV) is a plant RNA virus, naturally infecting Hydrangea macrophylla . Here, we report the first genomic sequences of two HdRSV isolates from hydrangea plants in Japan. The overall nucleotide sequences of these Japanese isolates were 96.0 to 96.3% identical to those of known European isolates.

Identification and characterization of a Hydrangea ringspot virus isolate infecting hydrangea in São Paulo State

Hydrangea plants showing leaves with chlorotic and necrotic rings from Arujá Municipality, São Paulo State, were analyzed for the identification of the viral species. Elongated filamentous particles of 490 nm were visualized under transmission electron microscope. Oligonucleotides for Hydrangea ringspot virus (HdRSV), a potexvirus commonly found in Europe and in the United States, were tested using total RNA from hydrangea plants, amplifying two fragments, one around 550 and another one of 250 nucleotides. Nucleotide identity with HdRSV (accession number AJ 707100.1) was 96% and 88% for the longest and shortest fragment, respectively, indicating the presence of this virus. To evaluate its dissemination in the matrices of hydrangea used in the commercial production, 17 samples were collected in the region of Arujá, and eight were infected by HdRSV. For the analyzed viral replicase portion, the isolates from the varieties 'Azul LZR', 'Rosita', 'Renat Blue' and 'Vermelho Comum' did not differ in their amino acid sequences from isolates with sequences deposited in the GenBank (accession numbers AY 707100 and NC_006943). The isolates from 'Azul Rendado' and "Rosa Japonesa' showed few differences but were related to the remaining isolates. An antiserum was obtained for HdRSV and can be efficiently used to detect such virus in hydrangea and Primula malacoides, another ornamental plant also infected by HdRSV.

Identification and Properties of a Carlavirus Causing Chlorotic Mottle of Florists' Hydrangea (H. macrophylla) in the United States

A previously uncharacterized virus with flexuous filamentous particles 660 nm in length was identified in the United States in florists' hydrangea (Hydrangea macrophylla), in which it caused chlorotic mottling, leaf deformation, and discoloration. The virus, tentatively named Hydrangea chlorotic mottle virus (HdCMV), was transmitted readily by mechanical inoculation and by Myzus persicae, but infected only H. macrophylla. The amino acid sequence of a 1.7-kb amplicon comprising the 3′ terminus of the HdCMV genome contained one partial and three complete putative open reading frames (ORFs) most similar in size, arrangement, and sequence to the homologous regions of the genomes of known carlaviruses. Based on virion morphology, genome properties, and current criteria for species demarcation, it was concluded that HdCMV represented a new species in the genus Carlavirus. Hydrangea ringspot virus (HdRSV, genus Potexvirus) occurred in mixed infections with HdCMV, but the two viruses could be distinguished readily by serological tests.