Abstract
BACKGROUND: Improving saccharification efficiency in bioenergy crop species remains an important challenge. Here, we report the characterization of a Sorghum (Sorghum bicolor L.) mutant, named REDforGREEN (RG), as a bioenergy feedstock.
RESULTS: It was found that RG displayed increased accumulation of lignin in leaves and depletion in the stems, antithetic to the trend observed in wild type. Consistent with these measurements, the RG leaf tissue displayed reduced saccharification efficiency whereas the stem saccharification efficiency increased relative to wild type. Reduced lignin was linked to improved saccharification in RG stems, but a chemical shift to greater S:G ratios in RG stem lignin was also observed. Similarities in cellulose content and structure by XRD-analysis support the correlation between increased saccharification properties and reduced lignin instead of changes in the cellulose composition and/or structure.
CONCLUSION: Antithetic lignin accumulation was observed in the RG mutant leaf-and stem-tissue, which resulted in greater saccharification efficiency in the RG stem and differential thermochemical product yield in high lignin leaves. Thus, the red leaf coloration of the RG mutant represents a potential marker for improved conversion of stem cellulose to fermentable sugars in the C4 grass Sorghum.
Document Type
Article
Publication Date
10-9-2013
Digital Object Identifier (DOI)
http://dx.doi.org/10.1186/1754-6834-6-146
Repository Citation
Petti, Carloalberto; Harman-Ware, Anne E.; Tateno, Mizuki; Kushwaha, Rekha; Shearer, Andrew; Downie, A. Bruce; Crocker, Mark; and DeBolt, Seth, "Sorghum mutant RG displays antithetic leaf shoot lignin accumulation resulting in improved stem saccharification properties" (2013). Horticulture Faculty Publications. 15.
https://uknowledge.uky.edu/horticulture_facpub/15
X-RAY diffraction (XRD) analyses of RG and wild type biomass. In A, diffractograms generated from RG and wild type leaf material and corresponding relative cristallinity index (RCI) values. In B, XRD of stem biomasses and associated RCI values.
Additional file 2, Figure S2.jpeg (5133 kB)
X-RAY diffraction (XRD) analyses of RG and wild type semi-purified cellulose. In A, diffractograms generated from RG and wild type semi-purified cellulose from leaf material and corresponding relative cristallinity index (RCI) values. In B, XRD of semi-purifed cellulose from stem biomasses and associated RCI values.
Additional file 3, Table S1.docx (103 kB)
Pyro-GC/MS analysis of WT biomass [Leaf (WTL) and Stem (WTS)].
Additional file 4, Table S2.docx (108 kB)
Pryo-GC/MS analysis of RG biomass [Leaf (RGL) and Stem (RGS)].
Additional file 5, Figure S3.jpeg (5052 kB)
Representative pyrograms of wild type stem and leaf biomass. Numbered peaks on the chromatograms correspond to the peaks reported in Additional file 3: TableS1 and they are typical products seen from pyrolysis of different biomass types. (9) Furfural; (19) phenol; (20) 2-methoxyphenol, (31) 4-vinylphenol; (32) 2-methoxy-4-vinylphenol (35) 2,6-dimethoxyphenol and (45) 4-vinylsyringol.
Additional file 6, Figure S4.jpeg (4907 kB)
Representative pyrograms of RG mutant stem and leaf biomass. Numbered peaks on the chromatograms correspond to the peaks reported in Additional file 4: Table S2 and they are typical products seen from pyrolysis of different biomass types. (9) Furfural; (19) phenol; (20) 2-methoxyphenol, (31) 4-vinylphenol; (32) 2-methoxy-4-vinylphenol (35) 2,6-dimethoxyphenol and (45) 4-.
Additional file 7, Table S3.docx (54 kB)
Ultimate analysis of biomass samples.
Additional file 8, Table S4.docx (76 kB)
List of genes in the phenylpropanoid pathway investigated by RT-PCR.
Notes/Citation Information
Published in Biotechnology for Biofuels, v. 6, 147.
© 2013 Petti et al.; licensee BioMed Central Ltd.
This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.