Plant Pathology (2007) 56, 346 Doi: 10.1111/j.1365-3059.2007.01517.x Journal compilation © 2007 BSPP 346 No claim to original US government works Blackwell Publishing Ltd NEW DISEASE REPORT First report of a phytoplasma associated with Christmas cactus witches’ broom H. Cai*, H. R. Chen, B. H. Kong, G. H. Yang and T. Liu The Center for Agricultural Biodiversity Research and Training of Yunnan Province, Yunnan Agricultural University, Kunming, China 650201 The Christmas cactus (Zygocactus truncatus) is a perennial succulent and is native to the South American tropics of Brazil. It is one of the most widely cultivated plants and healthy Christmas cacti in full bloom are often sold as holiday plants around the Christmas season. A pot containing a Christmas cactus with cladodes showing conspicuous malformed branches giving witches’ broom symptoms and stunted growth was found at the Agricultural University, Kunming. Based on the symptomatology, a phyto- plasma was suspected to be associated with the disease. Samples from the plant exhibiting witches’ broom and symptomless plants were analyzed for the presence of phytoplasmas using 16SrDNA PCR assays. Total nucleic acids were extracted from young cladodes using the DNeasy Plant Mini kit (QIAGEN) and were used as the template in a nested PCR reaction employing primers R16mF2/R16mR1 followed by R16F2/R16R2 (Gundersen & Lee, 1996). A water control was also included in all the PCR reactions to check for any contamination. A DNA fragment of the expected size (1·2 kb) was amplified by nested PCR from the diseased plant but not from symptomless plants, nor from the water control. After cloning and sequencing, the DNA sequence of 1249 bp was deposited in GenBank (Accession No. AY647459). Phylogenetic analysis of the 16S rDNA sequence delineated the Christmas cactus witches’ broom phytoplasma as a Peanut witches’-broom (16SrII) group member (putative Candidatus Phytoplasma aurantifolia), most closely related to the faba bean phyllody phytoplasma (Lee et al., 1998). This is the first report of a phytoplasma disease of the Christmas cactus. Acknowledgements This work was supported by the National Natural Science Foundation of China (grant no. 30260064) and the Science Fund of Yunnan Province (grant no. 2000C0014Q). References Gundersen, DE, Lee, IM, 1996. Ultrasensitive detection of phytoplasmas by nested-PCR assays using two universal primer pairs. Phytopathologia Mediterranea 35, 144–51. Lee IM, Gundersen-Rindal DE, Davis RE, Bartoszyk IM, 1998. Revised classification scheme of phytoplasmas based on RFLP analyses of 16S rRNA and ribosomal protein gene sequences. International Journal of Systematic Bacteriology 48, 1153–69. *E-mail: caihong0623@126.com. Accepted 19 June 2006 at www.bspp.org.uk/ndr where figures relating to this paper can be viewed. First detection of ‘Candidatus Phytoplasma australiense’ in Liquidambar styraciflua in Australia N. Habili a *, N. Farrokhi b and J. W. Randles a a Waite Diagnostics, School of Agriculture, Food & Wine, Waite Campus, University of Adelaide SA5005, Australia; and b Department of Biological Sciences, California State University, Long Beach, CA 90840, USA Liquidambar styraciflua (sweet gum; Family Hamamelidaceae) is an ornamental tree native to North America, producing a hard wood suitable for the furniture industry. A liquidambar tree on the Waite Campus, Urrbrae, South Australia had symptoms of a chronic patchy chlorosis of the crown and dieback of apical and lateral branches, when compared to five other trees each about 40 years old growing in the same roadside verge. During late summer (March), chlorotic shoots typically bore fewer and smaller leaves with tip necrosis and vein clearing which senesced earlier than healthy trees in autumn. The number of fruits on the tree was reduced. Total nucleic acids were extracted and tested by nested PCR using primers P1/P7, followed by R16F2n/m23sr specific for the 16S rRNA gene of all known phytoplasmas. The PCR product (1600 bp) was cloned and sequenced (GenBank Accession No. DQ660363). It was compared with those of 8 other phytoplasmas using equal weight maximum parsimony analyses with bootstrap support for each of the clades with a branch and bound search within PAUP 4·0 using an anaeroplasma (Acc. No. M25050) as the outgroup. Although the liquidambar and strawberry lethal yellows phytoplasma (Acc. No. AJ243045) were in the same clade, differences in the clade length indicated that the two sequences were not identical. The strains within the clade belong to ‘Candidatus Phytoplasma australiense’, of the 16Sr XIIB group (Lee et al., 2000). Although the presence of Aus- tralian grapevine yellows (AGY) was suspected, PCR with strain-specific primers for AGY (Davis et al., 1997) gave negative results. We propose the name liquidambar yellows for this disease. Acknowledgements We would like to acknowledge the assistance of Dr. Simon Malcomber from California State University, Long Beach, USA, with generating the phylogenetic tree. References Davis RE, Dally EL, Gundersen DE, Lee, I-M, Habili N, 1997. ‘Candidatus Phytoplasma australiense’, a new phytoplasma taxon associated with Australian grapevine yellows. International Journal of Systematic Bacteriology 47, 262–9. Lee I-M, Davis RE, Gundersen-Rindal DE, 2000. Phytoplasma: phytopathogenic Mollicutes, Annual Review of Microbiology 54, 221– 55. *E-mail: nuredin.habili@adelaide.edu.au. Accepted 6 September 2006 at www.bspp.org.uk/ndr where figures relating to this paper can be viewed. Plant Pathology (2007) 56, 346 Doi: 10.1111/j.1365-3059.2007.01537.x © 2007 The Authors Journal compilation © 2007 BSPP