Submitted to: Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: November 21, 2007
Publication Date: January 15, 2008
Citation: Ralph, J. 2008. Streamlined method for biomass whole-cell-wall structural profiling. In: Proceedings of Plant and Animal Genome XVI. January 15, 2008, San Diego, California. p. 85. Technical Abstract: In wide-ranging research aimed at altering plant cell wall characteristics by conventional breeding or modern genetic methods, one of the biggest problems is in delineating the effects on the cell wall. Plant cell walls are a complex conglomerate of a variety of polysaccharides and lignin. Although other methods have their place and can be more rapid (e.g., NIR), the difficulty in interpretation of some spectral methods, or the destruction of structure by chemical methods, assures that key features of cell walls that benefit, e.g., biomass production and conversion, are lost. A promising recent approach is the dissolution of the whole cell wall and high-resolution solution-state NMR analysis. This year, we have improved the NMR acquisition and developed chemometrics methods to utilize the NMR fingerprint from 2D 13C-1H correlation spectra on acetylated cell walls to differentiate and delineate structural changes in, for example, transgenics from wild-type control plants, tension wood from normal wood, etc. We have also developed two promising new avenues toward more rapid in-NMR-tube sample preparation. The first is to utilize DMSO-d6 and N-methylimidazole-d6 directly for the dissolution, without derivatization. The second is to simply produce gels of ball-milled cell walls directly in DMSO-d6 and to utilize 2D NMR directly on the gel-state samples. The former method provides particularly high-resolution spectra with outstanding dispersion of some polysaccharide and lignin components (over our now conventional acetylated cell wall samples). The second method allows 2D spectra to be acquired rapidly (in as little as 30 min per sample), but with lower resolution. Although improvements are required, the methods to utilize NMR to analyze 20-50 samples per day appear to be within reach.