RUI: Molecular Phylogenetic Analysis and Biogeography of Spiroplasmas

Abstract

Laura Regassa

DEB 0451430

Spiroplasmas may be one of the most abundant groups of microbes on earth due to their association with a wide variety of insects. Traditional strain classification divided the genus Spiroplasma into 34 groups based on serology, and recent molecular analysis of 36 strains from North America and Europe suggests a strong correlation between the molecular phylogeny and the serological groups. The current project will expand upon this initial study to include more geographically diverse spiroplasma isolates. The results will address questions concerning geographical diversification, spiroplasma-host specificity, and the correlation between serological classification and molecular phylogeny. Specifically, the research will examine the molecular phylogenetic relationships of a geographically and serologically diverse sample set of novel spiroplasma isolates from tabanid flies. Tabanid-associated spiroplasmas were chosen because they are the most thoroughly studied group to date based on serology. The spiroplasma isolates for this study were obtained from tabanid flies in North America, Meso-America, South America and Australia; and were placed into 24 independent serogroups. Isolates from each serogroup will be subjected to molecular analysis and molecular phylogenetic relationships will be determined.

Results from this study will move the spiroplasma field forward to greater reliance on DNA sequence data for strain classification and help to bridge the gap between traditional serology and molecular phylogeny. This has important implications for the spiroplasma field, because a correlation between serology and phylogeny would allow for tentative placement of hundreds of strains that have only been classified serologically. In addition, understanding the biodiversity and biogeography of spiroplasmas has important practical applications in agricultural production, as pathogenic species are responsible for citrus stubborn disease, corn stunt disease and honeybee mortality. Assignment of geographical ranges and distribution patterns for spiroplasmas may help with disease management strategies. Finally, this research provides numerous opportunities for the career development of undergraduate students, graduate students (M.S.), and the Principal Investigator. This project will broadly impact participation of underrepresented groups as over 80% of the Principal Investigator's undergraduate research students have been from underrepresented groups.