title: Label-free in situ imaging of lignification in the cell wall of low lignin transgenic Populus trichocarpa.
abstract: Chemical imaging by confocal Raman microscopy has been used for the visualization of the cellulose and lignin distribution in wood cell walls. Lignin reduction in wood can be achieved by, for example, transgenic suppression of a monolignol biosynthesis gene encoding 4-coumarate-CoA ligase (4CL). Here, we use confocal Raman microscopy to compare lignification in wild type and lignin-reduced 4CL transgenic Populus trichocarpa stem wood with spatial resolution that is sub-microm. Analyzing the lignin Raman bands in the spectral region between 1,600 and 1,700 cm(-1), differences in lignin signal intensity and localization are mapped in situ. Transgenic reduction of lignin is particularly pronounced in the S2 wall layer of fibers, suggesting that such transgenic approach may help overcome cell wall recalcitrance to wood saccharification. Spatial heterogeneity in the lignin composition, in particular with regard to ethylenic residues, is observed in both samples.
authors.affiliation: Energy Biosciences Institute, University of California, Berkeley, CA 94720, USA.
authors.forename: M
authors.initials: M
authors.lastname: Schmidt
authors.forename: A M
authors.initials: AM
authors.lastname: Schwartzberg
authors.forename: P N
authors.initials: PN
authors.lastname: Perera
authors.forename: A
authors.initials: A
authors.lastname: Weber-Bargioni
authors.forename: A
authors.initials: A
authors.lastname: Carroll
authors.forename: P
authors.initials: P
authors.lastname: Sarkar
authors.forename: E
authors.initials: E
authors.lastname: Bosneaga
authors.forename: J J
authors.initials: JJ
authors.lastname: Urban
authors.forename: J
authors.initials: J
authors.lastname: Song
authors.forename: M Y
authors.initials: MY
authors.lastname: Balakshin
authors.forename: E A
authors.initials: EA
authors.lastname: Capanema
authors.forename: M
authors.initials: M
authors.lastname: Auer
authors.forename: P D
authors.initials: PD
authors.lastname: Adams
authors.forename: V L
authors.initials: VL
authors.lastname: Chiang
authors.forename: P James
authors.initials: PJ
authors.lastname: Schuck
mesh_terms: D002473:Cell Wall / Q000378:metabolism*; D008031:Lignin / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000166:cytology / Q000378:metabolism*; D032107:Populus / Q000166:cytology / Q000378:metabolism*; D013059:Spectrum Analysis, Raman
chemical_list: D008031:Lignin