title: Suppression of CCR impacts metabolite profile and cell wall composition in Pinus radiata tracheary elements.
abstract: Suppression of the lignin-related gene cinnamoyl-CoA reductase (CCR) in the Pinus radiata tracheary element (TE) system impacted both the metabolite profile and the cell wall matrix in CCR-RNAi lines. UPLC-MS/MS-based metabolite profiling identified elevated levels of p-coumaroyl hexose, caffeic acid hexoside and ferulic acid hexoside in CCR-RNAi lines, indicating a redirection of metabolite flow within phenylpropanoid metabolism. Dilignols derived from coniferyl alcohol such as G(8-5)G, G(8-O-4)G and isodihydrodehydrodiconiferyl alcohol (IDDDC) were substantially depleted, providing evidence for CCR's involvement in coniferyl alcohol biosynthesis. Severe CCR suppression almost halved lignin content in TEs based on a depletion of both H-type and G-type lignin, providing evidence for CCR's involvement in the biosynthesis of both lignin types. 2D-NMR studies revealed minor changes in the H:G-ratio and consequently a largely unchanged interunit linkage distribution in the lignin polymer. However, unusual cell wall components including ferulate and unsaturated fatty acids were identified in TEs by thioacidolysis, pyrolysis-GC/MS and/or 2D-NMR in CCR-RNAi lines, providing new insights into the consequences of CCR suppression in pine. Interestingly, CCR suppression substantially promoted pyrolytic breakdown of cell wall polysaccharides, a phenotype most likely caused by the incorporation of acidic compounds into the cell wall matrix in CCR-RNAi lines.
authors.affiliation: Scion, Private Bag 3020, Rotorua, New Zealand. armin.wagner@scionresearch.com
authors.forename: Armin
authors.initials: A
authors.lastname: Wagner
authors.forename: Yuki
authors.initials: Y
authors.lastname: Tobimatsu
authors.forename: Geert
authors.initials: G
authors.lastname: Goeminne
authors.forename: Lorelle
authors.initials: L
authors.lastname: Phillips
authors.forename: Heather
authors.initials: H
authors.lastname: Flint
authors.forename: Diane
authors.initials: D
authors.lastname: Steward
authors.forename: Kirk
authors.initials: K
authors.lastname: Torr
authors.forename: Lloyd
authors.initials: L
authors.lastname: Donaldson
authors.forename: Wout
authors.initials: W
authors.lastname: Boerjan
authors.forename: John
authors.initials: J
authors.lastname: Ralph
mesh_terms: D000445:Aldehyde Oxidoreductases / Q000037:antagonists & inhibitors* / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D001483:Base Sequence; D002473:Cell Wall / Q000737:chemistry / Q000378:metabolism; D018744:DNA, Plant / Q000235:genetics; D017343:Genes, Plant; D008031:Lignin / Q000096:biosynthesis; D055442:Metabolome; D008969:Molecular Sequence Data; D009005:Monosaccharides / Q000032:analysis; D019906:Nuclear Magnetic Resonance, Biomolecular; D028223:Pinus / Q000235:genetics* / Q000378:metabolism*; D010940:Plant Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D034622:RNA Interference; D017386:Sequence Homology, Amino Acid
chemical_list: D018744:DNA, Plant; D009005:Monosaccharides; D010940:Plant Proteins; D008031:Lignin; D000445:Aldehyde Oxidoreductases; C019904:cinnamoyl CoA reductase