Raman imaging: An indispensable technique to comprehend the functionalization of lignocellulosic material

Multimodal imaging analysis in silver fir reveals coordination in cellulose and lignin deposition

“…In this study, we present a comprehensive analysis of tracheid lignification in silver fir by combining spatial information derived from RMS and temporal dynamics reconstructed from TLM and CLSM images. RMS chemical imaging provides molecular insights into cell wall composition by using unique spectral fingerprints to identify compounds being particularly useful for lignin detection ( Gierlinger et al 2012 ; Guillon et al 2022 ; Leng et al 2022 ). However, the long time required to obtain and process RMS spectra may limit a widespread application in xylogenesis studies, which typically require observations on numerous samples ( Rathgeber et al 2016 ).…”

“…The scattering RMS bands were assigned in accordance with Leng et al (2022) . RMS chemical images were obtained by measuring the integrated intensities from signal to baseline in the ranges 995 to 1,009 (centered at 1,003), 1,085 to 1,105 (centered at 1,096), 1,112 to 1,173 (centered at ∼1,127), and 1,592 to 1,604 (centered at 1,599) cm −1 for Histolaque proteins, cellulose, cellulose and hemicelluloses, and lignin, respectively.…”

“…Lignin also contributes to woody plants’ defense against pathogens, increasing their resistance to degradation by microbial attack ( Ranade et al 2022 ). On the other hand, multiple industrial uses of lignocellulosic materials highlight the major economic importance of lignin biosynthesis, including the development of materials such as wood–polymer composites, lignin-based adhesives, nanoparticles, or carbon fibers among others ( Norgren and Edlund 2014 ; Leng et al 2022 ). However, although tree-ring research has contributed to shedding light on the environmental constraints of lignification ( Piermattei et al 2020 ), the underpinnings of the interaction between xylem developmental factors and climate are still far from being understood.…”

“…Thus, some authors have proposed to label lignin with fluorescent dyes and antibodies to visualize lignin-rich tissues ( Kitin et al 2003 ; Joseleau and Ruel 2006 ; Bond et al 2008 ; Tobimatsu et al 2013 ; Kitin et al 2020 ; Balzano et al 2021 ). On the other hand, analytical tools such as confocal Raman microspectroscopy (RMS) have been used to study the chemistry of cell wall, as it renders spatial information on the distribution of lignin and other cell wall constituents ( Agarwal 1999 ; Gierlinger et al 2012 ; Guillon et al 2022 ; Leng et al 2022 ). Therefore, combining TLM-derived observations with spatial information provided by CLSM and RMS could bring valuable information on the dynamics of lignification.…”

Advances in single-cell metabolomics to unravel cellular heterogeneity in plant biology

“…While these steps have been evaluated in terms of cellulose yield, it would be useful to visualize the molecular properties of LCMs directly, so that it is possible to determine quickly which components and steps of the cell wall have been acted upon. To simultaneously know the location and components that are changing in the cell wall, a combination of spatial correlation Raman scattering and SIMS imaging was used to allow evaluation from the same location and the same sample ( Li et al 2010 ), and analysis in Miscanthus ( Miscanthus × giganteus ) which made increased resolution possible ( Leng et al 2022 ).…”