Hyperthermostable Enzyme (lactonases) for use as Microbial Biocontrol Agents for Plant Diseases

University of Minnesota/Dr. Michael Sadowski

Numerous bacterial pathogens infect crop plants, representing major economic burdens, and limit our ability to feed the world’s populations. Current methods for controlling plant diseases due to bacterial infection have had limited success, in part due to bacterial resistance and specificity. Novel strategies are therefore greatly needed to control microbes. Numerous bacterial pathogens use chemical signaling systems to coordinate virulence factor expression and biofilm formation. A common bacterial communication mechanism called quorum sensing (QS) regulates bacterial gene expression in response to fluctuations in cell density. A common class of QS molecules are acyl homoserine lactones (AHLs). The hydrolysis of AHLs lead to the disruption of bacterial communication, and a subsequent reduction of biofilm formation and virulence. The use of a controlled biologically-derived agent, e.g. a lactonase preparation, to control plant pathogens, is therefore appealing.

Our group has isolated and engineered enzymes that are highly proficient and extremely stable, that can be used as biocontrol agents and be active at all times, independently of the ecosystem. We propose to use these unique molecules and examine their potential to protect a variety of plants, including corn, from infection and examine their ability to reduce post-harvest damage to crops during storage.