Characterization and Ectopic Expression of a Populus Hydroxyacid Hyd roxyci n nam oylt ra nsferase  

作　　者：Ai-Xia Cheng Jin-Ying Gou Xiao-Hong Yu Huijun Yang Xin Fang Xiao-Ya Chen Chang-Jun Liu 

机构地区：[1]Biosciences Department, Brookhaven National Laboratory, Upton, NY 11973, USA [2]School of Pharmaceutical Sciences, Shandong University, :linan 250012, China [3]Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Shanghai 200032, China

出　　处：《Molecular Plant》2013年第6期1889-1903,共15页分子植物（英文版）

基　　金：the Division of Chemical Sciences,Geosciences,and Biosciences,Office of Basic Energy Sciences of the US Department of Energy (DOE)，the transgenic Arabidopsis analyses were also partially supported by National Science Foundation，by the oversea collaborative project of National Science Foundation of China

摘　　要：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 contri- bution 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 ~0-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.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 contri- bution 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 ~0-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.

关 键 词：CUTIN SUBERIN FERULATE BAHD ACYLTRANSFERASE Populus. 

分 类 号：S792.119[农业科学—林木遗传育种] Q255[农业科学—林学]