Using <i>Populus</i> as a lignocellulosic feedstock for bioethanol

Porth, Ilga; El‐Kassaby, Yousry A.

doi:10.1002/biot.201400194

Cited by 59 publications

(34 citation statements)

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“…Populus trichocarpa and P. balsamifera are sibling poplar species of the section Tacamahaca that diverged in allopatry rather recently (~76 Ka) during Pleistocene glaciations (Levsen et al 2012) [see (Ismail et al 2012) for an alternativeolderestimate]. They are major components of the forest ecosystems of northern North America and are economically important forest trees, being wood pulp sources and potential feedstock for cellulosic ethanol production (Jansson & Douglas 2007;Porth & El-Kassaby 2015). Despite their recent divergence and morphological similarity, with some minor differences in flower and fruit morphology, the species are ecologically divergent and adapted to strongly contrasting environments.…”

Section: Introductionmentioning

confidence: 99%

Genomic and functional approaches reveal a case of adaptive introgression fromPopulus balsamifera(balsam poplar) inP. trichocarpa(black cottonwood)

et al. 2016

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Natural hybrid zones in forest trees provide systems to study the transfer of adaptive genetic variation by introgression. Previous landscape genomic studies in Populus trichocarpa, a keystone tree species, indicated genomic footprints of admixture with its sister species Populus balsamifera and identified candidate genes for local adaptation. Here, we explored the patterns of introgression and signals of local adaptation in P. trichocarpa and P. balsamifera, employing genome resequencing data from three chromosomes in pure species and admixed individuals from wild populations. Local ancestry analysis in admixed P. trichocarpa revealed a telomeric region in chromosome 15 with P. balsamifera ancestry, containing several candidate genes for local adaptation. Genomic analyses revealed signals of selection in certain genes in this region (e.g. PRR5, COMT1), and functional analyses based on gene expression variation and correlations with adaptive phenotypes suggest distinct functions of the introgressed alleles. In contrast, a block of genes in chromosome 12 paralogous to the introgressed region showed no signs of introgression or signatures of selection. We hypothesize that the introgressed region in chromosome 15 has introduced modular or cassette-like variation into P. trichocarpa. These linked adaptive mutations are associated with a block of genes in chromosome 15 that appear to have undergone neo- or subfunctionalization relative to paralogs in a duplicated region on chromosome 12 that show no signatures of adaptive variation. The association between P. balsamifera introgressed alleles with the expression of adaptive traits in P. trichocarpa supports the hypothesis that this is a case of adaptive introgression in an ecologically important foundation species.

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Section: Introductionmentioning

confidence: 99%

Genomic and functional approaches reveal a case of adaptive introgression fromPopulus balsamifera(balsam poplar) inP. trichocarpa(black cottonwood)

et al. 2016

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“…Lignocellulosic biomass production is met with the challenge to enhance yields and improve physical and chemical traits to become a sustainable, carbon–neutral renewable energy source [1, 2]. Energy produced from lignocellulosic crops will help alleviate our current high dependency on fossil fuels and reduce greenhouse gas emissions responsible for global warming.…”

Section: Introductionmentioning

confidence: 99%

Impact of RAV1-engineering on poplar biomass production: a short-rotation coppice field trial

Moreno-Cortés

Ramos-Sánchez

Hernández‐Verdeja

et al. 2017

Biotechnol Biofuels

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BackgroundEarly branching or syllepsis has been positively correlated with high biomass yields in short-rotation coppice (SRC) poplar plantations, which could represent an important lignocellulosic feedstock for the production of second-generation bioenergy. In prior work, we generated hybrid poplars overexpressing the chestnut gene RELATED TO ABI3/VP1 1 (CsRAV1), which featured c. 80% more sylleptic branches than non-modified trees in growth chambers. Given the high plasticity of syllepsis, we established a field trial to monitor the performance of these trees under outdoor conditions and a SRC management.ResultsWe examined two CsRAV1-overexpression poplar events for their ability to maintain syllepsis and their potential to enhance biomass production. Two poplar events with reduced expression of the CsRAV1 homologous poplar genes PtaRAV1 and PtaRAV2 were also included in the trial. Under our culture conditions, CsRAV1-overexpression poplars continued developing syllepsis over two cultivation cycles. Biomass production increased on completion of the first cycle for one of the overexpression events, showing unaltered structural, chemical, or combustion wood properties. On completion of the second cycle, aerial growth and biomass yields of both overexpression events were reduced as compared to the control.ConclusionsThese findings support the potential application of CsRAV1-overexpression to increase syllepsis in commercial elite trees without changing their wood quality. However, the syllepsis triggered by the introduction of this genetic modification appeared not to be sufficient to sustain and enhance biomass production.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-017-0795-z) contains supplementary material, which is available to authorized users.

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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.…”

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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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Using Populus as a lignocellulosic feedstock for bioethanol

Cited by 59 publications

References 145 publications

Genomic and functional approaches reveal a case of adaptive introgression fromPopulus balsamifera(balsam poplar) inP. trichocarpa(black cottonwood)

Genomic and functional approaches reveal a case of adaptive introgression fromPopulus balsamifera(balsam poplar) inP. trichocarpa(black cottonwood)

Impact of RAV1-engineering on poplar biomass production: a short-rotation coppice field trial

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

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