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Bumald spirea (Spiarea bumalda Burv.) is an important ornamental tree widely grown in northern China. In August of 2006, spirea plants exhibiting symptoms of witches'-broom, stunting, yellowing, and shoot dieback were found at an incidence of 5 to 15% in Qingzhou City, Shandong Province, China. Total DNA was extracted separately from 0.1 g of phloem tissue from leaf midribs and stems of six symptomatic and six asymptomatic plants with a modified cetyltriethylammonium bromide (CTAB) method (3). Resulting DNA samples were analyzed for phytoplasma DNA by a nested PCR assay using phytoplasma universal 16S rDNA gene primer pairs R16mF2/R16mR1 and R16F2n/R16R2 (2). These primers amplified 1.5- and 1.2-kb products, respectively, from DNA of all symptomatic plants only. Restriction fragment length polymorphism (RFLP) analysis of the 1.2-kb 16S rDNA product using enzymes AluI, MseI, and HhaI indicated that all symptomatic plants contained a group 16SrI (aster yellows group) subgroup B (16SrI-B) phytoplasma strain (4). A 16S rDNA sequence derived from this strain (GenBank Accession No. EF176608) was most similar (99.8 and 99.6%) to those of severe aster yellows (GenBank Accession No. M86340) and Maryland aster yellows (GenBank Accession No. AF322644) phytoplasmas, respectively, thereby confirming strain identity based on RFLP analysis. A phytoplasma (Spiarea stunt phytoplasma, GenBank Accession No. AF190228), which belongs to X-disease group (16SrIII), was reported to infect spirea and probably be lethal to S. tomentosa in New York (1,4). The phytoplasma reported here shared low identity (90.8%) with Spiarea stunt phytoplasma, but also caused dieback of spirea shoots. The epidemiology and economic impact of this disease need further intensive investigation. To our knowledge, this is the first report of spirea witches'-broom disease and of its association with a subgroup 16SrI-B phytoplasma in China. References: (1) H. M. Griffiths et al. Can. J. Plant Pathol. 16:255, 1994. (2) D. E. Gundersen and I.-M. Lee. Phytopathol. Mediterr. 35:144, 1996. (3) Y. Qi et al. Biotechnol. Bull. 4:44, 2004. (4) The IRPCM Phytoplasma/Spiroplasma Working Team-Phytoplasma Taxonomy Group. Int. J. Syst. Bacteriol. 54:1243, 2004.

Hibiscus rosa-sinensis Linn., family Malvaceae, is an attractive horticultural plant originating from China. Five viruses infecting H. rosa-sinensis that have been characterized previously are Hibiscus chlorotic ringspot virus (HCRSV, genus Carmovirus), Hibiscus latent ringspot virus (HLRSV, genus Nepovirus), Hibiscus yellow mosaic virus (genus Tobamovirus), Eggplant mottled dwarf virus (EMDV, genus Nucleorhabdovirus), and Okra mosaic virus (OkMV, genus Tymovirus) (2). Recently, two novel tobamoviruses infecting H. rosa-sinensis were characterized in Singapore and Florida (1). In this study, viral symptoms were observed on H. rosa-sinensis in Nanyang City in Henan Province, China. The systemic symptoms included dark and light green mosaic in young leaves, leaf puckering and malformation on older leaves, and significant stunting. Rod-shaped virus particles were isolated from H. rosa-sinensis expressing systemic symptoms. The virus was transmitted mechanically to 10 species from three families. Symptoms expressed on these plants included systemic leaf chlorosis and distortion on Lycopersicum esculentum, systemic mosaic on Capsicum annuum, Nicotiana tabacum, and Physalis floridana, and systemic chlorosis on Glycine max. N. tabacum-Xanthi nc and Datura stramonium were asymptomatic. The virus also produced chlorotic and necrotic local lesions on Chenopodium quinoa, C. amaranticolor, and C. murale. The virus was propagated in L. esculentum, N. tabacum, and P. floridana. Virions purified from systemically infected N. tabacum contained a single-stranded RNA of approximately 6.4 kb and a coat protein (CP) of approximately 17.6 kDa. The double-stranded RNA profile revealed a single band of approximately 6.4 kb. Sap extracted from virus-infected plants reacted positive with an antiserum prepared against Tobacco mosaic virus (TMV) using an antigen-coated plate enzyme-linked immunosorbent assay. The CP gene was amplified by reverse transcription-polymerase chain reaction with primers specific to Tomato mosaic virus (ToMV) and sequence data obtained from the resulting amplification product. The CP gene consisting of 159 amino acids (GenBank Accession No. AY313136) shared 99.37% identity with the ToMV Queensland isolate (GenBank Accession No. AF332868). On the basis of biology, serology, properties of virions, and the sequence of the CP gene, we conclude that the virus isolated from H. rosa-sinensis in China is Tomato mosaic virus(ToMV). References: (1) S. Adkins et al. Plant Dis. 87:1190, 2003. (2) M. H. V. van Regenmortel et al., eds. Virus Taxonomy. 7th Report of the ICTV, Academic Press, NY, 2000.