Project Number: 1275-22000-246-00-D
Project Type: Appropriated
Start Date: Feb 26, 2007
End Date: Feb 25, 2012
Establish molecular biomarkers of evolutionary divergence for spiroplasma and phytoplasma detection and identification. Expand the molecular scheme for phytoplasma classification through genome-based selection of "constellations of identifier genes". Identify and characterize plant pathogenic mollicute genes involved in pathogenesis and symptom induction for eventual establishment of identifiers of pathotypes. Determine the correlation of chromosomally-integrated repetitive sequences and extrachromosomal DNAs in genome plasticity and biological diversity of phytoplasmas.
Genome-based information will form the basis for improving detection, identification, and classification of plant pathogenic, wall-less prokaryotes (class Mollicutes). Gene sequencing, bioinformatics methods, recombinant DNA technology, phylogenetic and gene evolution analyses, enzyme and bacterial growth assays, gene function analyses, and biochemical methods will be employed with inoculations of susceptible plants, tissue culture and plant transformation, to investigate the structure and function of DNA sequences and gene products as molecular markers for detection and identification of genus-, species-, and strain-level evolutionary divergence. Phytoplasmas associated with newly emerging diseases will be identified, and molecular criteria for improving descriptions of 'Candidatus Phytoplasma' species and for developing a formal taxonomy will be sought. DNA sequences enabling genome plasticity and biological diversity will be investigated as potential molecular biomarkers for making finer distinctions at species, strain, and population levels. Agrobacterium-mediated stable transformation and plant viral vector-mediated transient expression technologies will be used to introduce antimicrobial peptide genes and other defense-related genes into plants, enhancing natural plant defense and mitigating phytoplasmal and spiroplasmal diseases.