title: Three homologous genes encoding sn-glycerol-3-phosphate acyltransferase 4 exhibit different expression patterns and functional divergence in Brassica napus.
abstract: Brassica napus is an allotetraploid (AACC) formed from the fusion of two diploid progenitors, Brassica rapa (AA) and Brassica oleracea (CC). Polyploidy and genome-wide rearrangement during the evolution process have resulted in genes that are present as multiple homologs in the B. napus genome. In this study, three B. napus homologous genes encoding endoplasmic reticulum-bound sn-glycerol-3-phosphate acyltransferase 4 (GPAT4) were identified and characterized. Although the three GPAT4 homologs share a high sequence similarity, they exhibit different expression patterns and altered epigenetic features. Heterologous expression in yeast further revealed that the three BnGPAT4 homologs encoded functional GPAT enzymes but with different levels of polypeptide accumulation. Complementation of the Arabidopsis (Arabidopsis thaliana) gpat4 gpat8 double mutant line with individual BnGPAT4 homologs suggested their physiological roles in cuticle formation. Analysis of gpat4 RNA interference lines of B. napus revealed that the BnGPAT4 deficiency resulted in reduced cutin content and altered stomatal structures in leaves. Our results revealed that the BnGPAT4 homologs have evolved into functionally divergent forms and play important roles in cutin synthesis and stomatal development.
authors.affiliation: Agricultural Lipid Biotechnology Program, Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada T6H 2P5.
authors.forename: Xue
authors.initials: X
authors.lastname: Chen
authors.forename: Martin
authors.initials: M
authors.lastname: Truksa
authors.forename: Crystal L
authors.initials: CL
authors.lastname: Snyder
authors.forename: Aliaa
authors.initials: A
authors.lastname: El-Mezawy
authors.forename: Saleh
authors.initials: S
authors.lastname: Shah
authors.forename: Randall J
authors.initials: RJ
authors.lastname: Weselake
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics; D001483:Base Sequence; D029688:Brassica napus / Q000201:enzymology / Q000235:genetics*; D003001:Cloning, Molecular; D004721:Endoplasmic Reticulum / Q000201:enzymology; D057890:Epigenomics; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D005992:Glycerol-3-Phosphate O-Acyltransferase / Q000235:genetics / Q000378:metabolism*; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008563:Membrane Lipids / Q000032:analysis; D008969:Molecular Sequence Data; D009154:Mutation; D010802:Phylogeny; D018515:Plant Leaves / Q000737:chemistry / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D054046:Plant Stomata / Q000502:physiology; D034622:RNA Interference; D018749:RNA, Plant / Q000235:genetics; D057891:Tetraploidy
chemical_list: D007527:Isoenzymes; D008563:Membrane Lipids; D010940:Plant Proteins; D018749:RNA, Plant; C000521:cutin; D005992:Glycerol-3-Phosphate O-Acyltransferase