Area of Interest: Plant Molecular and Developmental Biology
My research interests are focused on the molecular genetics and developmental biology of the higher plant Arabidopsis thaliana. Arabidopsis, a member of the mustard family, possesses a number of characteristics which make it an excellent model system for the study of plant biology. Some of these are: small plant size, short generation time, prolific seed production and a small simply organized genome.
The specific long term goal of my research is to elucidate the physiological functions of lipoxygenase (LOX) in higher plants, using a combination of molecular biological, genetic and biochemical approaches. While the physiological roles of LOX in plants have not been well defined, it is clear that the enzyme is involved in a number of essential processes, including growth and development and the response to biotic and abiotic stresses. Furthermore, the primary products of the LOX reaction, fatty acid hydroperoxides, are precursors to regulatory molecules in both plant and animal cells. Jasmonates, the best characterized of these in plants, are phytohormones which have been shown to effect a number of physiological processes including the regulation of gene expression. Jasmonates have also been implicated as signal transduction molecules in the response of plants to pathogen attack and wounding.
The plants in which LOX has been studied to date have large numbers of LOX genes and isozymes that have complicated analysis of it's physiological function. In order to utilize a simpler system I have initiated a molecular physiological study of LOX in the model crucifer, Arabidopsis thaliana. The work of my laboratory and that of my collaborators, Drs. Erin Bell and John Mullet, indicates that Arabidopsis contains two LOX genes and is in fact much simpler than other plants in this regard. In my laboratory we have isolated and characterized cDNA and genomic clones for the LOX1 gene of Arabidopsis. We have demonstrated that this gene is induced in response to bacterial pathogen attack and by the phytohormones, methyl jasmonate and abscisic acid. In addition we have shown that LOX activity and LOX1 expression peak during seed germination, consistent with a role in early development. Finally, to facilitate analysis of LOX protein levels, a LOX1 maltose binding fusion protein was produced in E. coli and used to produce polyclonal antibodies. I now have in hand all of the molecular tools required to analyze and manipulate the expression of the LOX1 gene in Arabidopsis. I am presently using these tools to study the role of the LOX1 gene in the defense response to bacterial pathogens and in seed germination. I am also exploring the use of the LOX1 induction by ABA and methyl jasmonate as a system for genetic analysis of phytohormone action in plants.