Sphingolipids have been demonstrated to play important roles as both membrane components and as signaling molecules involved in regulating cellular processes in animals and fungi. While sphingolipids are quantitatively important components of specific plant membranes and recent evidence indicates that sphingolipids serve as signaling molecules in plants, surprisingly little is known about plant sphingolipid function. This 2010 project focuses on the network of genes predicted to be involved in sphingolipid metabolism. Further information about the project including a list of the specific genes to be investigated is available at http://bio.usuhs.mil/2010.html. These genes will be identified and the functions of the encoded proteins (e.g., the specific reaction catalyzed by the gene product, its substrate specificity, subcellular location, expression and activity in tissues) will be determined. The specific roles of different sphingolipids in plants will be determined by characterizing the properties and behavior of mutant plants defective in specific sphingolipid metabolic genes and so incapable of synthesizing a given sphingolipid. This research will lead to an understanding of the role of sphingolipids in plant growth and development as well as the response of plants to biotic and abiotic stresses. This project will not only result in a profound increase in our understanding of the metabolism and function of plant sphingolipids per se, but it is anticipated that these efforts will also intersect with other 2010 projects focusing on signaling, disease resistance and glycosyltransferases. While the major results of the work will be published in scientific journals and presented at meetings, regular updates of progress and abstracts of published work and meetings presentations will be posted at the web address given above to facilitate information sharing. This collaborative effort involves five investigators at distinctly different institutions with the complementary expertise to successfully accomplish this work. All facets of this effort will involve post-doctoral associates, graduate students, undergraduates and high school students and it is expected that these individuals will develop an appreciation for the benefits of collaborative research.