Characterization of the actinomycetes from the rhizosphere of a desert shrub, big sagebrush (Artemisia tridentata), focusing on their production of novel antifungal antibiotics and bioactive secondary metabolites.
This dissertation describes investigations of the microbial ecology and antibiotic producing abilities of actinomycetes of a little studied desert habitat, the rhizospheres and soils associated with the desert shrub Big Sagebrush (Artemisia tridentata). The increase in the incidence of antibiotic resistance by pathogenic microbes, both in medicine and agriculture, has created a great need for the discovery of novel antibiotics. Novel bacteria from little explored environments are one such source of new antibiotics. One such habitat is the rhizosphere of Big Sagebrush. Based upon preliminary data accumulated in our laboratory, we hypothesized that this environment could be a reservoir of novel antibiotic producing actinomycetes highly adapted to that environment and producing a broad spectrum of antimicrobial bioactive secondary metabolites. The present studies confirmed our hypothesis that the rhizosphere and nearby soils associated with Big Sagebrush populations are a prolific source of actinomycetes, particularly Streptomyces species that produce broad spectrum antifungal compounds.