Hibiscus spp. are popular ornamental plants in New Zealand. The genus is susceptible to Hibiscus chlorotic ringspot virus (HCRSV), a member of the genus Carmovirus, which has been reported in Australia, El Salvador, Singapore, the South Pacific Islands, Taiwan, Thailand, and the United States (1--4). In May of 2004, chlorotic spotting and ringspots were observed on the leaves of two H. rosa-sinensis plants in a home garden in Auckland, New Zealand. When inoculated with sap from symptomatic leaves, Chenopodium quinoa and C. amaranticolor developed faint chlorotic local lesions 12 to 15 days later. Phaseolus vulgaris exhibited small necrotic local spots 10 days postinoculation. No symptoms were observed on inoculated plants of Cucumis sativus, Gomphrena globosa, Nicotiana Clevelandii, N. tabacum, or N. sylvestris. Plants of H. rosa-sinensis and the three symptomatic indicator species tested positive for HCRSV using polyclonal antiserum (Agdia Inc., Elkhart, IN) in a double antibody sandwich (DAS)-ELISA. Forward (5′-GGAACCCGTCCTGTTACTTC-3′) and reverse (5′-ATCACATCCACATCCCCTTC-3′) primers were designed on the basis of a conserved region in the coat protein gene (nt 2722--3278) of HCRSV isolates in GenBank (Accession Nos. X86448 and DQ392986). A product of the expected size (557 bp) was amplified by reverse transcription (RT)-PCR with total RNA extracted from the four infected species. Comparison of the sequence of the amplicon from H. rosa-sinensis (GenBank Accession No. EU554660) with HCRSV isolates from Singapore and Taiwan (GenBank Accession Nos. X86448 and DQ392986) showed 99 and 94% nucleotide identity, respectively. From 2006 to 2008, samples from a further 25 symptomatic hibiscus plants were collected from different locations in the Auckland region. Nineteen, including plants of H. diversifolius, H. rosa-sinensis, and H. syriacus, tested positive for HCRSV by RT-PCR. To our knowledge, this is the first report of HCRSV in New Zealand and of the virus in H. diversifolius and H. syriacus. HCRSV is considered to be widespread in New Zealand.
References: (1) A. A. Brunt et al. Plant Pathol. 49:798, 2000. (2) S. C. Li et al. Plant Pathol. 51:803, 2002. (3) H. Waterworth. No.227 in: Descriptions of Plant Viruses. CMI/AAB, Surrey, UK, 1980. (4) S. M. Wong et al. Acta Hortic. 432:76, 1996.
