9808559 Schnable Survival requires that organisms produce a protective barrier between themselves and their environment. Because organisms must be able to sense and respond to environmental signals, this barrier must also allow for an exchange of molecules and information. In plants, the cuticle serves as this barrier. In addition to functioning as a water barrier, it has been suggested that the cuticle provides frost and UV resistance and plays a role in plant-pathogen interactions. Furthermore, the nature of the cuticle greatly affects the deposition and behavior of agricultural chemicals such as pesticides, growth regulators and foliar nutrients sprayed on plants. Cuticular waxes are an important component of the cuticle. They are complex mixtures of acyl derivatives of very long-chain fatty acids made in plant epidermal cells by VLCFA elongase enzyme systems. A maize gene (gl8) responsible for the production of one of these enzymatic functions has been cloned, and the other genes required for the production of functional VLCFA elongase enzyme systems will be cloned. This integrated research approach will enhance our understanding of the mechanism by which the elongation of acyl chains occurs. Because similar types elongation reactions are important in the biosynthesis of many classes of molecules (including polyketides, flavonoids, and stilbenoids) which function as antibiotics, plant-pathogen toxins, pigments and protective compounds, the proposed studies will impact our understanding and ability to manipulate many fundamental biological processes
