title: Glycerol-3-phosphate acyltransferase 4 is essential for the normal development of reproductive organs and the embryo in Brassica napus.
abstract: The enzyme sn-glycerol-3-phosphate acyltransferase 4 (GPAT4) is involved in the biosynthesis of plant lipid poly-esters. The present study further characterizes the enzymatic activities of three endoplasmic reticulum-bound GPAT4 isoforms of Brassica napus and examines their roles in the development of reproductive organs and the embryo. All three BnGPAT4 isoforms exhibited sn-2 acyltransferase and phosphatase activities with dicarboxylic acid-CoA as acyl donor. When non-substituted acyl-CoA was used as acyl donor, the rate of acylation was considerably lower and phosphatase activity was not manifested. RNA interference (RNAi)-mediated down-regulation of all GPAT4 homologues in B. napus under the control of the napin promoter caused abnormal development of several reproductive organs and reduced seed set. Microscopic examination and reciprocal crosses revealed that both pollen grains and developing embryo sacs of the B. napus gpat4 lines were affected. The gpat4 mature embryos showed decreased cutin content and altered monomer composition. The defective embryo development further affected the oil body morphology, oil content, and fatty acid composition in gpat4 seeds. These results suggest that GPAT4 has a critical role in the development of reproductive organs and the seed of B. napus.
authors.affiliation: Agricultural Lipid Biotechnology Program, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada T6G 2P5.
authors.forename: Xue
authors.initials: X
authors.lastname: Chen
authors.affiliation: Agricultural Lipid Biotechnology Program, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada T6G 2P5.
authors.forename: Guanqun
authors.initials: G
authors.lastname: Chen
authors.affiliation: Agricultural Lipid Biotechnology Program, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada T6G 2P5.
authors.forename: Martin
authors.initials: M
authors.lastname: Truksa
authors.affiliation: Agricultural Lipid Biotechnology Program, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada T6G 2P5.
authors.forename: Crystal L
authors.initials: CL
authors.lastname: Snyder
authors.affiliation: Plant Biotechnology, Alberta Innovates-Technology Futures, Vegreville, Alberta, Canada T9C 1T4.
authors.forename: Saleh
authors.initials: S
authors.lastname: Shah
authors.affiliation: Agricultural Lipid Biotechnology Program, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada T6G 2P5 randall.weselake@ualberta.ca.
authors.forename: Randall J
authors.initials: RJ
authors.lastname: Weselake
mesh_terms: D029688:Brassica napus / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D005227:Fatty Acids / Q000378:metabolism; D035264:Flowers / Q000254:growth & development*; D005992:Glycerol-3-Phosphate O-Acyltransferase / Q000378:metabolism*; D005810:Multigene Family; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D010938:Plant Oils / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000254:growth & development* / Q000378:metabolism
chemical_list: D005227:Fatty Acids; D010938:Plant Oils; D010940:Plant Proteins; D005992:Glycerol-3-Phosphate O-Acyltransferase; D010744:Phosphoric Monoester Hydrolases
keywords: Brassica napus; GPAT; cutin biosynthesis; embryo development; female fertility; reproductive organ.