Spatial Scales of Genetic and Phenotypic Diversity Among Streptomycetes in Native Soils

9977907

Kinkel, L.

Samac, D.

This Microbial Observatory will provide fundamental information on the genetic and phenotypic diversity among Streptomycetes bacteria occurring in native soils at Cedar Creek Natural History Area, a Long Term Ecological Research site at the forest-prairie interface in central Minnesota. In particular, this work will provide significant insight into the dynamics of interisolate antibiotic inhibition, resistance, and induction within these communities, as well as a spatial, temporal, and genetic context for analyzing these phenotypic characters. The influence of soil nitrogen treatment on the community will also be evaluated here. The specific objectives of the research are to: 1. Evaluate the influence of nitrogen inputs on the Streptomycete community in soil. This will be done by contrasting the population densities of Streptomycetes in soils maintained at two different nitrogen input levels; contrasting the diversity of Streptomycete communities in soils maintained at the two nitrogen levels, specifically focusing on genetic diversity and diversity in antibiotic inhibition and resistance. 2. Quantify the genetic and phenotypic diversity in Streptomycetes across a range of spatial scales; quantifying genetic diversity among Streptomycetes in individual soil cores, in separate cores from the same plot, and from different plots; quantifying diversity in inhibition profiles among Streptomycetes in individual soil cores, in separate cores from the same plot, and from different plots; and quantifying diversity in resistance profiles among Streptomycetes in individual soil cores, in separate cores from the same plot, or from different plots. 3. Determine the influence of spatial origin, population density of the local community, and genetic relatedness on the potential for inhibition, resistance to inhibition, and antibiotic induction among Streptomycetes. This will by done by determining whether isolates from the same location (soil core), same plot, or same nitrogen treatment are more or less likely to inhibit, to resist inhibition by, or to induce antibiotic production than isolates from different soil cores, different plots, or different nitrogen treatments; determining whether isolates that are genetically closely related are more or less likely to inhibit one another, to resist inhibition by one another, or to induce antibiotic production in one another than isolates that are more distantly related; and determining whether isolates from high density locations in soil are more or less likely to inhibit other isolates, resist inhibition by others, or induce antibiotic production in others than isolates from low density locations. This information will provide fundamental insight into the potential significance of antibiotic interactions for evolution and microbial population dynamics in soils.