Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 8/24/2007
Publication Date: N/A
Interpretive Summary: Root and crown rots and wilts caused by soilborne pathogens cause billions of dollars in losses to food, fiber and biofuel crops. Biological control offers sustainable and environmentally friendly methods of controlling these pathogens. Biocontrol occurs through the introduction of microbial agents or stimulation of indigenous antagonistic microorganisms. Many biocontrol agents suppress pathogens through the productions of antifungal antibiotics in the soil and rhizosphere. Soil is the most difficult substrate from which to isolate and quantify biocontrol antibiotics. This review focuses on the isolation and detection of antibiotics produced by soil and rhizosphere microbes in situ. Quantification of an antifungal antibiotic produced by a biocontrol agent in the rhizosphere is critical to predicting whether an agent will provide disease suppression in a given soil against the target pathogen.
Technical Abstract: Antibiotics are small organic molecules of microbial origin that at low concentrations, are deleterious to the growth or metabolism of other microorganisms. More broadly, antibiotics constitute a functionally defined subset of the diverse array of bioactive metabolites produced by microorganisms in order to sense, communicate with, and influence the activities of other organisms in their environment. Many microorganisms from the soil and rhizosphere are capable of antibiotic production, and powerful molecular and bioanalytical tools have been developed to study the regulation and synthesis of these compounds in vitro. When applied in conjunction with techniques for manipulating soil and other environmental matrices, these tools also provide a means to understanding the biological role of antibiotics produced in natural microbial habitats. This chapter reviews factors affecting antibiotic synthesis, activity, and detection, describes methods for extracting and quantifying them, and discusses approaches for monitoring the effects of antibiotics produced in situ.