Project Abstract:

Sphingolipids were classically viewed as structural components of membranes, but recent studies in yeast and mammals have revealed that sphingolipids and their metabolites are also dynamic regulators of many cellular processes. In plants, however, very little is known about the metabolism and functions of sphingolipids. The goals of this 2010 proposal are: 1) to identify the Arabidopsis genes required for sphingolipid metabolism; 2) to assign precise functions to these genes; 3) to generate plants with defects in these specific genes 4) to characterize the phenotypes of these plants to determine the functions of sphingolipids in plants. Goals 1 and 2 will employ reverse genetics to assess the ability of putative Arabidopsis sphingolipid metabolism genes (18 gene families, with 1 to 15 genes per family) to complement yeast mutants lacking the endogenous gene and the effects of the heterologous expression of the Arabidopsis genes on sphingolipid profiles of the yeast. Goal 3 will involve screening insertion mutant collections to find knock-out mutations or other approaches such as post-transcriptional gene silencing and dominant negative mutations to generate plants defective in sphingolipid metabolism. In Goal 4, the phenotypes of these mutants will be characterized to reveal the function(s) of different sphingolipids in plants. A metabolomic approach to examine global metabolic consequences of perturbing sphingolipid synthesis as well as microarray technology to assess altered gene expression in mutants will also be used. This collaborative project, involving three labs with the collective expertise to accomplish the goals, will significantly increase our basic understanding of the metabolism and functions of plant sphingolipids. All facets of the collaboration will involve post-docs, graduate students and undergraduates at three very distinct institutions. Therefore, it will have an impact on the education of scientists in a comprehensive, interdisciplinary endeavor.