The research effort in our laboratory is divided into two primary areas. In this symbiosis, atmospheric dinitrogen is reduced to ammonia by the bacterium.
Ammonia is transferred to the plant where it is used for growth.
Our primary focus is on the enzymes phosphoenolpyruvate carboxylase, aspartate aminotransferase, glutamate synthase, asparagine and glutamine synthetases, and malate dehydrogenase. Together, these enzymes are responsible for the production of malate, which the endosymbiont uses as a carbon and energy source, and the amino acid asparagine, which is transported throughout the plant and used as a nitrogen source. We are currently characterizing these enzymes, studying the expression of the genes that encode them, and modifying enzyme activity in transgenic plants. We are also investigating the structure, expression, and function of the H1 histone genes and proteins in Arabidopsis thaliana . H1 histones are thought to have interrelated structural and regulatory functions in higher eukaryote chromatin.