Detection and Molecular Characterization of a 'Candidatus Phytoplasma asteris'-Related Strain Infecting Sasa fortunei in China.

Bamboos are ecologically and economically valuable plants. Young shoots of almost all species are edible, either raw or cooked, and are major components of Asian cuisine while culms are used for furniture or handicrafts as well as fuel wood. Symptoms indicative of phytoplasma disease were observed on Sasa fortunei (van Houtte) Fiori during a survey in Yangling, Shaanxi Province, China during 2007. Symptoms included internode shortening, a mosaic pattern on leaves of diminished size, stunted growth, and death of entire plants. Total nucleic acids were extracted from leaf veins of 10 diseased plants and 6 symptomless plants with a modified cetyltrimethylammoniumbromide (CTAB) method (1). Phytoplasma infection of plants was demonstrated by a nested PCR assay employing primer pair R16mF2/R16mR1 followed by R16F2n/R16R2 (2), which generated a 16S rDNA product of approximately 1.2 kb from all symptomatic plants only. Restriction fragment length polymorphism analysis by digestion of nested PCR products with restriction enzymes AluI and MseI indicated that S. fortunei plants contained group 16SrI (aster yellows), subgroup B phytoplasmas. Sequencing and phylogenetic analysis of phytoplasma 16S rDNA from S. fortunei (GenBank Accession No. FJ501958) revealed this strain to be very similar (99.7 and 99.6%, respectively) to phytoplasmas previously associated with Henon bamboo (Phyllostachys nigra) witches'-broom (GenBank Accession No. AB242433) (4) and sasa (S. borealis) witches'-broom (GenBank Accession No. AB293421) in Korea but less so (98.6%) to bamboo (Phyllostachys spp.) witches'-broom (GenBank Accession No. AY635145) disease in China (3). To our knowledge, this is the first report of a 'Ca. Phytoplasma asteris'-related strain infecting S. fortunei in China. References: (1) E. Angelini et al. Vitis 40:79, 2001. (2) D. E. Gundersen and I.-M. Lee. Phytopathol. Mediterr. 35:144, 1996. (3) C. Hong et al. Plant Prot. 31:39, 2005. (4) H. Jung et al. J. Gen. Plant Pathol. 72:261, 2006.