Very long chain fatty acids (VLCFAs), those that contain 20 or more carbon units, are incorporated into a wide variety of physiologically significant phytochemicals, including cuticular waxes, cutin, suberin, sphingolipids, and some phospholipids and seed oils. Genes that encode several of the enzymes involved in the production of VLCFAs have been isolated. Based on the finding that maize mutants that block the production of one of these enzymes are embryo lethal, VLCFAs must be essential during maize embryogenesis. Mutants that block the accumulation of essential VLCFAs therefore provide an ideal experimental system to determine the essential role of VLCFA-derived phytochemicals in plant development. The proposed project will define the essential developmental role(s) of VLCFAs, by determining the morphological differences that distinguish the development of mutant embryos from normal embryos. It will also establish which VLCFA-derived compound(s) are essential during embryo development, by comparing the accumulation of VLCFA-derived compounds in normal and mutant embryos. Finally, mutants that overcome the embryo lethality associated with genetic blocks in the production of VLCFAs will be isolated. In the long term, these mutants can be used to dissect the diverse network of biochemical pathways that utilize VLCFAs. The proposed studies meet the challenge of understanding the complex interplay between biochemistry and development by continuing to exploit the synergy inherent in a long-term research collaboration that integrates genetic and biochemical approaches. This project will provide excellent cross-disciplinary training experiences to a diverse group of early-career scientists because it will use a combination of hypothesis-driven and genome-wide analyses, and apply cutting-edge technologies to address significant questions in plant biology that have proven recalcitrant to a mono-disciplinary approach.
