Copper Tolerance of Bacterial Populations in the PhyllosphereEPA Grant Number: U914825
Title: Copper Tolerance of Bacterial Populations in the Phyllosphere
Investigators: Scheck, Heather J.
Institution: Oregon State University
EPA Project Officer: Michaud, Jayne
Project Period: January 1, 1995 through January 1, 1997
Project Amount: $102,000
RFA: STAR Graduate Fellowships (1995) Recipients Lists
Research Category: Academic Fellowships , Ecological Indicators/Assessment/Restoration , Fellowship - Ecology
The objectives of this research project are to: (1) measure how quickly a population of Pseudomonas syringae, a casual agent of bacterial blight of many woody plants, can become tolerant to copper under standard disease control programs; and (2) study the population dynamics of tolerant versus sensitive individuals in the presence and absence of copper sprays. Copper tolerant strains of P. syringae have been isolated from Northwest nurseries and fruit orchards. Growers have relied heavily on fixed copper compounds as bactericides, but because of copper tolerance, these products are no longer providing acceptable levels of disease control. A survey has shown that there are high levels of copper tolerance in populations of pathogenic P. syringae. Research has focused on understanding tolerance mechanisms at the molecular level, describing localized toxic effects in detail, but it has not addressed ecological aspects of microbial systems at the population level. This has hindered the extrapolation of the effects of bactericide tolerance detected in the laboratory to the field. Application of ecological concepts to bactericide tolerance analysis will lead to a more probabilistic approach to risk assessment. It also may indicate what parameters should be measured to estimate risk from pesticide tolerance in these agricultural systems, because it addresses ecological questions explicitly.