Dr. Burkey's graduate training was in plant biochemistry. He has conducted research on photosynthesis, studying the effects of light and genotype on several chloroplast proteins (chlorophyll-protein complexes, plastocyanin, ATP synthetase, Rubisco). Currently as a member of the USDA-ARS Plant Science Research Unit, Dr. Burkey conducts air pollution and climate change research to determine impacts of ozone, carbon dioxide, and temperature on agricultural crops and natural vegetation.
Ozone Effects on Crop Production
Ozone is a toxic gas formed in the atmosphere from pollutants (nitrogen oxides and hydrocarbons) produced during the combustion of fossil fuels. Ozone exposure causes characteristic visible injury on the foliage of sensitive plants. Ground-level ozone concentrations are sufficiently high in agricultural regions to inhibit plant growth and reduce yields.
Identification of Ozone-tolerant Varieties
In all crops examined to date, genetic variation in ozone sensitivity has been observed. Yield loss can be reduced by use of tolerant varieties. Dr. Burkey and colleagues screen snap bean, soybean, and wheat cultivars for differences in ozone response to identify tolerant lines and to understand the genetics of tolerance.
Ozone Tolerance Mechanisms and Future Crop Improvement
Plant characteristics and associated genes that confer ozone tolerance are not known. This limits the ability to screen for tolerance and prevents the use of molecular approaches to develop new varieties. A major objective of Dr. Burkey's program is to identify physiological and biochemical differences between ozone-sensitive and tolerant plants that account for the differences in ozone response. Current areas of investigation include stomatal limitation of ozone uptake, metabolism involved in the detoxification of ozone molecules that enter the leaf, and gene expression studies to indentify genes of interest that could be targeted to alter plant response to ozone.
Plants as biological indicators of ambient ozone
Genotype differences in ozone sensitivity can be utilized as biological indicator systems for monitoring ambient ozone levels. Scientists in the USDA-ARS Plant Science Research Unit have developed a system based on biomass production by ozone-sensitive and tolerant clover clones. Dr. Burkey and colleagues have developed ozone-sensitive and tolerant snap beans as an alternative system. Plant bio-indicators are valuable educational tools for increasing public awareness of air pollution problems. The snap bean system is being tested in the USA and Europe as an approach to detect and quantify ozone impacts on plants across regions of contrasting climatic conditions.