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The “Candidatus Phytoplasma” Concept: New Names but not yet a Taxonomy for the Fastidious Plant Pathogenic Mollicutes

  • G. Firrao

Abstract

The aetiology of what we now call phytoplasma diseases is perhaps the least understood in the history of plant pathology. Only in 1967 electron microscopy studies revealed that many diseases which were thought to be caused by viruses were actually associated with wall-less endo-cellular parasitic prokaryotic cells (reviewed in 1). Two different morphological types of wall-less prokaryotes were detected in plant phloem: the in vitro-cultivable helical-shaped wall-less prokaryotes were named spiroplasmas, while the non- helical pleomorphic forms that could not be cultivated in axenic media were simply called mycoplasma-like organisms (MLOs) as they resembled mycoplasmas on morphological grounds. Their early classification was based on the symptoms caused in the host and vector transmission characteristics (rev. in 1).

Keywords

Axenic Medium rRNA Operon Aster Yellow Mycoplasmalike Organism Plant Phloem 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    Harrison, N. A. 1999. Phytoplasma taxonomy. Proceedings of the First Internet Conference on Phytopathogenic Mollicutes.http://www.phytoplasma.uniud.it/conf.html
  2. 2.
    Murray, R. G. E., and Schleifer, K. H. 1994. Taxonomic notes: a proposal for recording the properties of putative taxa of procaryotes. Int. J. Syst. Bacteriol. 44: 174–176.PubMedCrossRefGoogle Scholar
  3. 3.
    Pettersson, B., Leitner, T., Ronaghi, M., Boske, G., Uhle M., and Johansson, K-E. 1996. Phylogeny of the Mycoplasma mycoides cluster as determined by sequence analysis of the 16S rRNA genes from the two rRNA operons. J. Bacteriol. 178:4131–4142.PubMedPubMedCentralGoogle Scholar
  4. 4.
    Sears, B. B., and Kirkpatrick, B. C. 1994. Unveiling the evolutionary relationships of plant-pathogenic mycoplasmalike organisms. American Society for Microbiology News 60: 307–312.Google Scholar
  5. 5.
    Weisburg, W.G., Tully, J.G., Rose, D.L., Petzel, J.P., Oyaizu, H., Yang, D., Mandelco, L., Sechrest, J., Lawrence, T.G., Vanetten, J., Maniloff, J., and Woese, C.R. 1989. A phylogenetic analysis of the mycoplasmas - basis for their classification. J. Bacteriol. 171: 6455–6467.PubMedPubMedCentralGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2001

Authors and Affiliations

  • G. Firrao
    • 1
  1. 1.Dipartimento di Biologia Applicata alla Difesa delle PianteUniversitàUdineItaly

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