title: An essential role of caffeoyl shikimate esterase in monolignol biosynthesis in Medicago truncatula.
abstract: Biochemical and genetic analyses have previously identified caffeoyl shikimate esterase (CSE) as an enzyme in the monolignol biosynthesis pathway in Arabidopsis thaliana, although the generality of this finding has been questioned. Here we show the presence of CSE genes and associated enzyme activity in barrel medic (Medicago truncatula, dicot, Leguminosae), poplar (Populus deltoides, dicot, Salicaceae), and switchgrass (Panicum virgatum, monocot, Poaceae). Loss of function of CSE in transposon insertion lines of M. truncatula results in severe dwarfing, altered development, reduction in lignin content, and preferential accumulation of hydroxyphenyl units in lignin, indicating that the CSE enzyme is critical for normal lignification in this species. However, the model grass Brachypodium distachyon and corn (Zea mays) do not possess orthologs of the currently characterized CSE genes, and crude protein extracts from stems of these species exhibit only a weak esterase activity with caffeoyl shikimate. Our results suggest that the reaction catalyzed by CSE may not be essential for lignification in all plant species.
authors.affiliation: BioDiscovery Institute, University of North Texas, Denton, TX, 76203, USA.|Department of Biological Sciences, University of North Texas, Denton, TX, 76203, USA.
authors.forename: Chan Man
authors.initials: CM
authors.lastname: Ha
authors.affiliation: BioDiscovery Institute, University of North Texas, Denton, TX, 76203, USA.|Department of Biological Sciences, University of North Texas, Denton, TX, 76203, USA.|BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
authors.forename: Luis
authors.initials: L
authors.lastname: Escamilla-Trevino
authors.affiliation: BioDiscovery Institute, University of North Texas, Denton, TX, 76203, USA.|Department of Biological Sciences, University of North Texas, Denton, TX, 76203, USA.|BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
authors.forename: Juan Carlos Serrani
authors.initials: JC
authors.lastname: Yarce
authors.affiliation: Department of Biochemistry, University of Wisconsin, Madison, WI, 53726, USA.|US Department of Energy, Great Lakes Bioenergy Research Center (GLBRC), Wisconsin Energy Institute, 1522 University Avenue, Madison, WI, 53726, USA.
authors.forename: Hoon
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Biochemistry, University of Wisconsin, Madison, WI, 53726, USA.|US Department of Energy, Great Lakes Bioenergy Research Center (GLBRC), Wisconsin Energy Institute, 1522 University Avenue, Madison, WI, 53726, USA.
authors.forename: John
authors.initials: J
authors.lastname: Ralph
authors.affiliation: BioDiscovery Institute, University of North Texas, Denton, TX, 76203, USA.|Department of Biological Sciences, University of North Texas, Denton, TX, 76203, USA.|BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
authors.forename: Fang
authors.initials: F
authors.lastname: Chen
authors.affiliation: BioDiscovery Institute, University of North Texas, Denton, TX, 76203, USA.|Department of Biological Sciences, University of North Texas, Denton, TX, 76203, USA.|BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Dixon
mesh_terms: D029681:Arabidopsis Proteins / Q000235:genetics*; D053898:Biosynthetic Pathways; D058431:Brachypodium / Q000235:genetics; D002265:Carboxylic Ester Hydrolases / Q000235:genetics*; D004950:Esterases / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D008031:Lignin / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D046913:Medicago truncatula / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D016254:Mutagenesis, Insertional; D008897:Panicum / Q000201:enzymology* / Q000235:genetics; D010641:Phenotype; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018547:Plant Stems / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D030821:Plants, Genetically Modified; D032107:Populus / Q000201:enzymology* / Q000235:genetics; D011994:Recombinant Proteins; D012765:Shikimic Acid / Q000737:chemistry / Q000378:metabolism; D014026:Nicotiana / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D003313:Zea mays / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D010940:Plant Proteins; D011994:Recombinant Proteins; D012765:Shikimic Acid; D008031:Lignin; D004950:Esterases; D002265:Carboxylic Ester Hydrolases; C583444:caffeoyl shikimate esterase, Arabidopsis
keywords: Brachypodium distachyon; Medicago truncatula; esterase; lignin biosynthesis; switchgrass