title: Characterization of two GL8 paralogs reveals that the 3-ketoacyl reductase component of fatty acid elongase is essential for maize (Zea mays L.) development.
abstract: Prior analyses established that the maize (Zea mays L.) gl8a gene encodes 3-ketoacyl reductase, a component of the fatty acid elongase required for the biosynthesis of very long chain fatty acids (VLCFAs). A paralogous gene, gl8b, has been identified that is 96% identical to gl8a. The gl8a and gl8b genes map to syntenic chromosomal regions, have similar, but not identical, expression patterns, and encode proteins that are 97% identical. Both of these genes are required for the normal accumulation of cuticular waxes on seedling leaves. The chemical composition of the cuticular waxes from gl8a and gl8b mutants indicates that these genes have at least overlapping, if not redundant, functions in cuticular wax biosynthesis. Although gl8a and gl8b double mutant kernels have endosperms that cannot be distinguished from wild-type siblings, these kernels are non-viable because their embryos fail to undergo normal development. Double mutant kernels accumulate substantially reduced levels of VLCFAs. VLCFAs are components of a variety of compounds, for example, cuticular waxes, suberin, and sphingolipids. Consistent with their essential nature in yeast, the accumulation of the ceramide moiety of sphingolipids is substantially reduced and their fatty acid composition altered in gl8a and gl8b double mutant kernels relative to wild-type kernels. Hence, we hypothesize that sphingolipids or other VLCFA-containing compounds are essential for normal embryo development.
authors.affiliation: Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA 50011, USA.
authors.forename: Charles R
authors.initials: CR
authors.lastname: Dietrich
authors.forename: M Ann D N
authors.initials: MA
authors.lastname: Perera
authors.forename: Marna
authors.initials: M
authors.lastname: D Yandeau-Nelson
authors.forename: Robert B
authors.initials: RB
authors.lastname: Meeley
authors.forename: Basil J
authors.initials: BJ
authors.lastname: Nikolau
authors.forename: Patrick S
authors.initials: PS
authors.lastname: Schnable
mesh_terms: D064431:3-Oxoacyl-(Acyl-Carrier-Protein) Reductase; D000123:Acetyltransferases / Q000235:genetics / Q000378:metabolism*; D000429:Alcohol Oxidoreductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000081031:Fatty Acid Elongases; D035264:Flowers / Q000201:enzymology / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D018506:Gene Expression Regulation, Plant / Q000502:physiology; D018525:Germination; D007527:Isoenzymes; D009154:Mutation; D010641:Phenotype; D018515:Plant Leaves / Q000201:enzymology / Q000254:growth & development; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000201:enzymology / Q000254:growth & development; D030821:Plants, Genetically Modified; D036226:Seedlings / Q000201:enzymology / Q000254:growth & development; D012639:Seeds; D003313:Zea mays / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development
chemical_list: D007527:Isoenzymes; D010940:Plant Proteins; D000429:Alcohol Oxidoreductases; C108981:glossy8 protein, Zea mays; D064431:3-Oxoacyl-(Acyl-Carrier-Protein) Reductase; D000123:Acetyltransferases; D000081031:Fatty Acid Elongases