Managing Soil Microbial Communities for Pathogen Control.

The activities of soil microorganisms benefit agricultural production in many ways, and deliberate management of soil microbial communities will be an important tool for enhancing agricultural productivity and sustainability. One important microbial function we would like to manage for is the ability to constrain the activity or population size of plant pathogens, particularly those that cause soil-borne diseases for which therapeutic treatment is not practical. Achieving this goal requires basic research into the factors that influence selection for pathogen-inhibitory phenotypes, as well as processes driving soil microbial community assembly, dynamics, and response to perturbation. The presentation will have three facets: 1) A theoretical framework for how resource diversity relates to selection for antibiotic production phenotypes among Streptomyces, suggesting that selection for these beneficial phenotypes is driven by microbial interactions. 2) The development of rhizosphere microbial communities from diverse bulk soil microbial community starting points, demonstrating that initial community composition sets limits on potential re-structuring of soil microbial communities. 3) Tracking microbial community succession in roots of winter cover crops after termination in the spring, illustrating spatial and temporal dynamics of plant pathogens in competition with saprotrophs in dead and dying plant tissue. This work contributes to the development of approaches to manage soil microbial communities for enhanced productivity and sustainability.