title: Knockdown of a laccase in Populus deltoides confers altered cell wall chemistry and increased sugar release.
abstract: Plant laccases are thought to function in the oxidation of monolignols which leads to higher order lignin formation. Only a hand-full of laccases in plants have been functionally evaluated, and as such little is known about the breadth of their impact on cell wall chemistry or structure. Here, we describe a previously uncharacterized laccase from Populus, encoded by locus Potri.008G064000, whose reduced expression resulted in transgenic Populus trees with changes in syringyl/guaiacyl ratios as well as altered sugar release phenotypes. These phenotypes are consistent with plant biomass exhibiting reduced recalcitrance. Interestingly, the transgene effect on recalcitrance is dependent on a mild pretreatment prior to chemical extraction of sugars. Metabolite profiling suggests the transgene modulates phenolics that are associated with the cell wall structure. We propose that this particular laccase has a range of functions related to oxidation of phenolics and conjugation of flavonoids that interact with lignin in the cell wall.
authors.affiliation: BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
authors.forename: Anthony C
authors.identifier: 0000-0003-0917-8705
authors.initials: AC
authors.lastname: Bryan
authors.affiliation: BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
authors.forename: Sara
authors.initials: S
authors.lastname: Jawdy
authors.affiliation: BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
authors.forename: Lee
authors.initials: L
authors.lastname: Gunter
authors.affiliation: The Biosciences Center, National Renewable Energy Laboratory, Golden, CO, USA.
authors.forename: Erica
authors.initials: E
authors.lastname: Gjersing
authors.affiliation: The Biosciences Center, National Renewable Energy Laboratory, Golden, CO, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Sykes
authors.affiliation: ArborGen Inc, Ridgeville, SC, USA.
authors.forename: Maud A W
authors.initials: MA
authors.lastname: Hinchee
authors.affiliation: ArborGen Inc, Ridgeville, SC, USA.
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Winkeler
authors.affiliation: ArborGen Inc, Ridgeville, SC, USA.
authors.forename: Cassandra M
authors.initials: CM
authors.lastname: Collins
authors.affiliation: BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
authors.forename: Nancy
authors.initials: N
authors.lastname: Engle
authors.affiliation: BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Tschaplinski
authors.affiliation: BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
authors.forename: Xiaohan
authors.initials: X
authors.lastname: Yang
authors.affiliation: BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
authors.forename: Gerald A
authors.initials: GA
authors.lastname: Tuskan
authors.affiliation: BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA. mucherow@ornl.gov.
authors.forename: Wellington
authors.initials: W
authors.lastname: Muchero
authors.affiliation: BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA. chenj@ornl.gov.
authors.forename: Jin-Gui
authors.initials: JG
authors.lastname: Chen
mesh_terms: D002473:Cell Wall / Q000737:chemistry* / Q000201:enzymology / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D042845:Laccase / Q000235:genetics / Q000378:metabolism*; D008031:Lignin / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000201:enzymology* / Q000235:genetics; D032107:Populus / Q000201:enzymology* / Q000235:genetics*; D014994:Xylose / Q000378:metabolism
chemical_list: D008031:Lignin; D014994:Xylose; D042845:Laccase
keywords: Populus; biofuel; cell wall; lignin; recalcitrance; xylose