title: Characterization and ectopic expression of a populus hydroxyacid hydroxycinnamoyltransferase.
abstract: Cutinized and suberized cell walls in plants constitute physiologically important environment interfaces. They act as barriers limiting the loss of water and nutrients and protecting against radiation and invasion of pathogens. The roles of cutin- and suberin polyesters are often attributed to their dominant aliphatic components, but the contribution of aromatic composition to their physiological function remains unclear. By functionally screening a subset of Populus trichocarpa BAHD/HXXXD acyltransferases, we identified a hydroxycinnamoyltransferase that shows specific transacylation activity on ω-hydroxyacids using both feruloyl- and p-coumaroyl- CoA as the acyl donors. We named this enzyme P. trichocarpa hydroxyacid/fatty alcohol hydroxycinnamoyltransferase 1 (PtFHT1). The ectopic expression of the PtFHT1 gene in Arabidopsis increased the incorporation of ferulate in root and seed suberins and in leaf cutin, but not that of p-coumarate, while the aliphatic load in both suberin and cutin polyesters essentially remained unaffected. The overaccumulation of ferulate in lipophilic polyester significantly increased the tolerance of transgenic plants to salt stress treatment; under sub-lethal conditions of salt stress, the ratios of their seed germination and seedling establishment were 50% higher than those of wild-type plants. Our study suggests that, although aromatics are the minor component of polyesters, they play important role in the sealing function of lipidic polymers in planta.
authors.affiliation: Biosciences Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
authors.forename: Ai-Xia
authors.initials: AX
authors.lastname: Cheng
authors.forename: Jin-Ying
authors.initials: JY
authors.lastname: Gou
authors.forename: Xiao-Hong
authors.initials: XH
authors.lastname: Yu
authors.forename: Huijun
authors.initials: H
authors.lastname: Yang
authors.forename: Xin
authors.initials: X
authors.lastname: Fang
authors.forename: Xiao-Ya
authors.initials: XY
authors.lastname: Chen
authors.forename: Chang-Jun
authors.initials: CJ
authors.lastname: Liu
mesh_terms: D000217:Acyltransferases / Q000378:metabolism*; D000222:Adaptation, Physiological; D008969:Molecular Sequence Data; D010802:Phylogeny; D018515:Plant Leaves / Q000201:enzymology; D010940:Plant Proteins / Q000378:metabolism; D018517:Plant Roots / Q000201:enzymology; D032107:Populus / Q000145:classification / Q000196:embryology / Q000201:enzymology*; D011994:Recombinant Proteins / Q000378:metabolism; D012639:Seeds / Q000201:enzymology; D012965:Sodium Chloride
chemical_list: D010940:Plant Proteins; D011994:Recombinant Proteins; D012965:Sodium Chloride; D000217:Acyltransferases
keywords: BAHD; Populus.; acyltransferase; cutin; ferulate; suberin