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Submitted to: Latin American Congress of Phytopathology and Brasilian Congress of Plant
Publication Type: Abstract Only Publication Acceptance Date: 8/29/2001 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Research on phytoplasmas (previously known as mycoplasmalike organisms, MLOs) and spiroplasmas is progressing at a rapid pace. Molecular methods are being widely adopted for detection, identification, classification, and phylogenetic studies of these unique phytopathogens. Analysis of the 16S rRNA and other conserved genes indicates broad phylogenetic diversity among phytoplasmas, and recent research has revealed previously unknown phytoplasmas in numerous plant diseases. A provisional nomenclature has been adopted for the description and naming of "Candidatus Phytoplasma species" based primarily on the sequence of the 16S rRNA gene. The hibiscus witches' broom phytoplasma, "Candidatus Phytoplasma brasiliense", from Brazil is he sixth "Candidatus Phytoplasma sp." to be published. Genomic sequencing of the corn stunt pathogen, Spiroplasma kunkelii, is currently underway. The sequence data are publicly available on the Internet. Approximately 1.45 Mb of the estimated 1.5 Mb genome has been sequenced, and the project is now in the gap closure phase. Preliminary analysis of the data reveals interesting features, including genes encoding presumptive proteins involved in the spiroplasma-insect vector interaction, putative cell division proteins, and repeated insertions of spiroplasma virus sequences in the S. kunkelii chromosome. Aspects of these recent findings will be discussed in relation to new insights they provide into the evolution of the cell wall-less, prokaryotic plant pathogens. |
