Bioenergy grass feedstock: current options and prospects for trait improvement using emerging genetic, genomic, and systems biology toolkits

Feltus, F. Alex; Vandenbrink, Joshua P.

doi:10.1186/1754-6834-5-80

Cited by 49 publications

(38 citation statements)

References 296 publications

(314 reference statements)

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“…Additionally, our results showed that C2-Idf plants have an increase in vegetative dry weight, which is a desirable trait for lignocellulosic crops (Feltus and Vandenbrink, 2012). The reason for this increase is not clear.…”

Section: Discussionmentioning

confidence: 73%

Silencing CHALCONE SYNTHASE in Maize Impedes the Incorporation of Tricin into Lignin and Increases Lignin Content

et al. 2016

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Lignin is a phenolic heteropolymer that is deposited in secondary-thickened cell walls, where it provides mechanical strength. A recent structural characterization of cell walls from monocot species showed that the flavone tricin is part of the native lignin polymer, where it is hypothesized to initiate lignin chains. In this study, we investigated the consequences of altered tricin levels on lignin structure and cell wall recalcitrance by phenolic profiling, nuclear magnetic resonance, and saccharification assays of the naturally silenced maize (Zea mays) C2-Idf (inhibitor diffuse) mutant, defective in the CHALCONE SYNTHASE Colorless2 (C2) gene. We show that the C2-Idf mutant produces highly reduced levels of apigenin-and tricin-related flavonoids, resulting in a strongly reduced incorporation of tricin into the lignin polymer. Moreover, the lignin was enriched in b-b and b-5 units, lending support to the contention that tricin acts to initiate lignin chains and that, in the absence of tricin, more monolignol dimerization reactions occur. In addition, the C2-Idf mutation resulted in strikingly higher Klason lignin levels in the leaves. As a consequence, the leaves of C2-Idf mutants had significantly reduced saccharification efficiencies compared with those of control plants. These findings are instructive for lignin engineering strategies to improve biomass processing and biochemical production.

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Section: Discussionmentioning

confidence: 73%

Silencing CHALCONE SYNTHASE in Maize Impedes the Incorporation of Tricin into Lignin and Increases Lignin Content

et al. 2016

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“…The lignocellulosic biomass derived from plant cell walls is the most abundant global renewable carbon source (2), stemming from either agricultural or forestry residuals or from dedicated energy crops. While improvement in lignocellulosic feedstock for biofuel applications via advanced breeding or genetic engineering appears feasible and is critical for the future of this industry (3)(4)(5), another key technical parameter that has potential for additional optimization is the identification of new enzymes and/or cofactors that could improve the efficacy of lignocellulosic biochemical processing.…”

mentioning

confidence: 99%

Gene Expression Patterns of Wood Decay Fungi Postia placenta and Phanerochaete chrysosporium Are Influenced by Wood Substrate Composition during Degradation

Skyba

Cullen

Douglas

et al. 2016

Appl Environ Microbiol

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Identification of the specific genes and enzymes involved in the fungal degradation of lignocellulosic biomass derived from feedstocks with various compositions is essential to the development of improved bioenergy processes. In order to elucidate the effect of substrate composition on gene expression in wood-rotting fungi, we employed microarrays based on the annotated genomes of the brown-and white-rot fungi, Rhodonia placenta (formerly Postia placenta) and Phanerochaete chrysosporium, respectively. We monitored the expression of genes involved in the enzymatic deconstruction of the cell walls of three 4-year-old Populus trichocarpa (poplar) trees of genotypes with distinct cell wall chemistries, selected from a population of several hundred trees grown in a common garden. The woody substrates were incubated with wood decay fungi for 10, 20, and 30 days. An analysis of transcript abundance in all pairwise comparisons highlighted 64 and 84 differentially expressed genes (>2-fold, P < 0.05) in P. chrysosporium and P. placenta, respectively. Cross-fungal comparisons also revealed an array of highly differentially expressed genes (>4-fold, P < 0.01) across different substrates and time points. These results clearly demonstrate that gene expression profiles of P. chrysosporium and P. placenta are influenced by wood substrate composition and the duration of incubation. Many of the significantly expressed genes encode "proteins of unknown function," and determining their role in lignocellulose degradation presents opportunities and challenges for future research. IMPORTANCEThis study describes the variation in expression patterns of two wood-degrading fungi (brown-and white-rot fungi) during colonization and incubation on three different naturally occurring poplar substrates of differing chemical compositions, over time. The results clearly show that the two fungi respond differentially to their substrates and that several known and, more interestingly, currently unknown genes are highly misregulated in response to various substrate compositions. These findings highlight the need to characterize several unknown proteins for catalytic function but also as potential candidate proteins to improve the efficiency of enzymatic cocktails to degrade lignocellulosic substrates in industrial applications, such as in a biochemically based bioenergy platform. In an attempt to reduce societal dependence on fossil fuels and consequently aid in the alleviation of associated economic and environmental concerns regarding the exploitation of petroleum reserves, biofuels derived from renewable and domestic sources have received extensive interest in recent years (1). The lignocellulosic biomass derived from plant cell walls is the most abundant global renewable carbon source (2), stemming from either agricultural or forestry residuals or from dedicated energy crops. While improvement in lignocellulosic feedstock for biofuel applications via advanced breeding or genetic engineering appears feasible and is critical for the future...

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“…For example, many North American prairie grasses produce a high yield with minimal fertilizer input and they contain a very high fiber content indicating a high level of cellulose and hemicellulose [2]. A high concentration of cellulose and hemicellulose can be released by treatment of grass biomass [3]. Subsequent cellulase and xylanase treatment of the treated biomass has been found to release glucose and xylose [3,4].…”

Section: Bioconversionmentioning

confidence: 99%

“…A high concentration of cellulose and hemicellulose can be released by treatment of grass biomass [3]. Subsequent cellulase and xylanase treatment of the treated biomass has been found to release glucose and xylose [3,4]. The fermentable glucose released from the hydrolyzed cellulose following enzymatic treatment of the biomass can be converted to chemicals such as citric acid, fumaric acid, gluconic acid, itaconic acid, lactic acid, malic acid, oxalic acid, propionic acid and succinic acid as well as biopolymers such as polysaccharide gums by microbial strains.…”

Section: Bioconversionmentioning

confidence: 99%

Plant Biomass from Grasses: An Underutilized Feedstock for Microbial Production of Chemicals and Biopolymers

West¹

2013

Microb Biochem Technol

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Plant biomass from grasses is an underutilized feedstock for the microbial production of chemicals and biopolymers. Hydrolysates of this type of plant biomass provide sufficient levels of glucose or xylose to support specialty chemical and biopolymer production. Considering the availability of these grasses worldwide, additional studies are needed to determine whether the production of industrially important chemicals and biopolymers from grasses using microbial bioconversion is feasible.

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Bioenergy grass feedstock: current options and prospects for trait improvement using emerging genetic, genomic, and systems biology toolkits

Cited by 49 publications

References 296 publications

Silencing CHALCONE SYNTHASE in Maize Impedes the Incorporation of Tricin into Lignin and Increases Lignin Content

Silencing CHALCONE SYNTHASE in Maize Impedes the Incorporation of Tricin into Lignin and Increases Lignin Content

Gene Expression Patterns of Wood Decay Fungi Postia placenta and Phanerochaete chrysosporium Are Influenced by Wood Substrate Composition during Degradation

Plant Biomass from Grasses: An Underutilized Feedstock for Microbial Production of Chemicals and Biopolymers

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