TY - JOUR
T1 - Downregulation of cinnamoyl-coenzyme a reductase in poplar
T2 - Multiple-level phenotyping reveals effects on cell wall polymer metabolism and structure
AU - Leplé, Jean Charles
AU - Dauwe, Rebecca
AU - Morreel, Kris
AU - Storme, Véronique
AU - Lapierre, Catherine
AU - Pollet, Brigitte
AU - Naumann, Annette
AU - Kang, Kyu Young
AU - Kim, Hoon
AU - Ruel, Katia
AU - Lefèbvre, Andrée
AU - Joseleau, Jean Paul
AU - Grima-Pettenati, Jacqueline
AU - De Rycke, Riet
AU - Andersson-Gunnerås, Sara
AU - Erban, Alexander
AU - Fehrle, Ines
AU - Petit-Conil, Michel
AU - Kopka, Joachim
AU - Polle, Andrea
AU - Messens, Eric
AU - Sundberg, Björn
AU - Mansfield, Shawn D.
AU - Ralph, John
AU - Pilate, Gilles
AU - Boerjan, Wout
PY - 2007/11
Y1 - 2007/11
N2 - Cinnamoyl-CoA reductase (CCR) catalyzes the penultimate step in monolignol biosynthesis. We show that downregulation of CCR in transgenic poplar (Populus tremula x Populus alba) was associated with up to 50% reduced lignin content and an orange-brown, often patchy, coloration of the outer xylem. Thioacidolysis, nuclear magnetic resonance (NMR), immunocytochemistry of lignin epitopes, and oligolignol profiling indicated that lignin was relatively more reduced in syringyl than in guaiacyl units. The cohesion of the walls was affected, particularly at sites that are generally richer in syringyl units in wild-type poplar. Ferulic acid was incorporated into the lignin via ether bonds, as evidenced independently by thioacidolysis and by NMR. A synthetic lignin incorporating ferulic acid had a red-brown coloration, suggesting that the xylem coloration was due to the presence of ferulic acid during lignification. Elevated ferulic acid levels were also observed in the form of esters. Transcript and metabolite profiling were used as comprehensive phenotyping tools to investigate how CCR downregulation impacted metabolism and the biosynthesis of other cell wall polymers. Both methods suggested reduced biosynthesis and increased breakdown or remodeling of noncellulosic cell wall polymers, which was further supported by Fourier transform infrared spectroscopy and wet chemistry analysis. The reduced levels of lignin and hemicellulose were associated with an increased proportion of cellulose. Furthermore, the transcript and metabolite profiling data pointed toward a stress response induced by the altered cell wall structure. Finally, chemical pulping of wood derived from 5-year-old, field-grown transgenic lines revealed improved pulping characteristics, but growth was affected in all transgenic lines tested.
AB - Cinnamoyl-CoA reductase (CCR) catalyzes the penultimate step in monolignol biosynthesis. We show that downregulation of CCR in transgenic poplar (Populus tremula x Populus alba) was associated with up to 50% reduced lignin content and an orange-brown, often patchy, coloration of the outer xylem. Thioacidolysis, nuclear magnetic resonance (NMR), immunocytochemistry of lignin epitopes, and oligolignol profiling indicated that lignin was relatively more reduced in syringyl than in guaiacyl units. The cohesion of the walls was affected, particularly at sites that are generally richer in syringyl units in wild-type poplar. Ferulic acid was incorporated into the lignin via ether bonds, as evidenced independently by thioacidolysis and by NMR. A synthetic lignin incorporating ferulic acid had a red-brown coloration, suggesting that the xylem coloration was due to the presence of ferulic acid during lignification. Elevated ferulic acid levels were also observed in the form of esters. Transcript and metabolite profiling were used as comprehensive phenotyping tools to investigate how CCR downregulation impacted metabolism and the biosynthesis of other cell wall polymers. Both methods suggested reduced biosynthesis and increased breakdown or remodeling of noncellulosic cell wall polymers, which was further supported by Fourier transform infrared spectroscopy and wet chemistry analysis. The reduced levels of lignin and hemicellulose were associated with an increased proportion of cellulose. Furthermore, the transcript and metabolite profiling data pointed toward a stress response induced by the altered cell wall structure. Finally, chemical pulping of wood derived from 5-year-old, field-grown transgenic lines revealed improved pulping characteristics, but growth was affected in all transgenic lines tested.
UR - http://www.scopus.com/inward/record.url?scp=37849044667&partnerID=8YFLogxK
U2 - 10.1105/tpc.107.054148
DO - 10.1105/tpc.107.054148
M3 - Article
C2 - 18024569
AN - SCOPUS:37849044667
SN - 1040-4651
VL - 19
SP - 3669
EP - 3691
JO - Plant Cell
JF - Plant Cell
IS - 11
ER -