Non-targeted discovery of high-value bio-products in Nicotiana glauca L: a potential renewable plant feedstock.

The evaluation of plant-based feedstocks is an important aspect of biorefining. Nicotiana glauca is a solanaceous, non-food crop that produces large amounts of biomass and is well adapted to grow in suboptimal conditions. In the present article, compatible sequential solvent extractions were applied to N.

Engineering Curcumin Biosynthesis in Poplar Affects Lignification and Biomass Yield.

Lignocellulosic biomass is recalcitrant toward deconstruction into simple sugars mainly due to the presence of lignin. By engineering plants to partially replace traditional lignin monomers with alternative ones, lignin degradability and extractability can be enhanced. Previously, the alternative monomer curcumin has been successfully produced and incorporated into lignified cell walls of Arabidopsis by the heterologous expression of () and ().

Field and saccharification performances of poplars severely downregulated in CAD1.

Lignin is one of the main factors causing lignocellulosic biomass recalcitrance to enzymatic hydrolysis. Glasshouse-grown poplars severely downregulated for CINNAMYL ALCOHOL DEHYDROGENASE 1 (CAD1), the enzyme catalysing the last step in the monolignol-specific branch of lignin biosynthesis, have increased saccharification yields and normal growth. Here, we assess the performance of these hpCAD poplars in the field under short rotation coppice culture for two consecutive rotations of 1 yr and 3 yr.

Rewired phenolic metabolism and improved saccharification efficiency of a Zea mays cinnamyl alcohol dehydrogenase 2 (zmcad2) mutant.

Lignocellulosic biomass is an abundant byproduct from cereal crops that can potentially be valorized as a feedstock to produce biomaterials. Zea mays CINNAMYL ALCOHOL DEHYDROGENASE 2 (ZmCAD2) is involved in lignification, and is a promising target to improve the cellulose-to-glucose conversion of maize stover. Here, we analyzed a field-grown zmcad2 Mutator transposon insertional mutant.

Alterations in the phenylpropanoid pathway affect poplar ability for ectomycorrhizal colonisation and susceptibility to root-knot nematodes.

This study investigates the impact of the alteration of the monolignol biosynthesis pathway on the establishment of the in vitro interaction of poplar roots either with a mutualistic ectomycorrhizal fungus or with a pathogenic root-knot nematode. Overall, the five studied transgenic lines downregulated for caffeoyl-CoA O-methyltransferase (CCoAOMT), caffeic acid O-methyltransferase (COMT), cinnamoyl-CoA reductase (CCR), cinnamyl alcohol dehydrogenase (CAD) or both COMT and CAD displayed a lower mycorrhizal colonisation percentage, indicating a lower ability for establishing mutualistic interaction than the wild-type. The susceptibility to root-knot nematode infection was variable in the five lines, and the CAD-deficient line was found to be less susceptible than the wild-type.

Polyploidy Affects Plant Growth and Alters Cell Wall Composition.

Polyploidization has played a key role in plant breeding and crop improvement. Although its potential to increase biomass yield is well described, the effect of polyploidization on biomass composition has largely remained unexplored. Here, we generated a series of Arabidopsis () plants with different somatic ploidy levels (2n, 4n, 6n, and 8n) and performed rigorous phenotypic characterization.

Stacking of a low-lignin trait with an increased guaiacyl and 5-hydroxyguaiacyl unit trait leads to additive and synergistic effects on saccharification efficiency in .

Background: Lignocellulosic biomass, such as wood and straw, is an interesting feedstock for the production of fermentable sugars. However, mainly due to the presence of lignin, this type of biomass is recalcitrant to saccharification. In Arabidopsis, lignocellulosic biomass with a lower lignin content or with lignin with an increased fraction of guaiacyl (G) and 5-hydroxyguaiacyl (5H) units shows an increased saccharification efficiency.

The effect of altered lignin composition on mechanical properties of CINNAMYL ALCOHOL DEHYDROGENASE (CAD) deficient poplars.

CAD-deficient poplars enabled studying the influence of altered lignin composition on mechanical properties. Severe alterations in lignin composition did not influence the mechanical properties. Wood represents a hierarchical fiber-composite material with excellent mechanical properties.

Silencing Affects Lignification and Improves Saccharification in Poplar.

Caffeoyl shikimate esterase (CSE) was recently shown to play an essential role in lignin biosynthesis in Arabidopsis () and later in However, the general function of this enzyme was recently questioned by the apparent lack of CSE activity in lignifying tissues of different plant species. Here, we show that down-regulation of in hybrid poplar ( × ) resulted in up to 25% reduced lignin deposition, increased levels of -hydroxyphenyl units in the lignin polymer, and a relatively higher cellulose content. The transgenic trees were morphologically indistinguishable from the wild type.

Different Routes for Conifer- and Sinapaldehyde and Higher Saccharification upon Deficiency in the Dehydrogenase CAD1.

In the search for renewable energy sources, genetic engineering is a promising strategy to improve plant cell wall composition for biofuel and bioproducts generation. Lignin is a major factor determining saccharification efficiency and, therefore, is a prime target to engineer. Here, lignin content and composition were modified in poplar ( × ) by specifically down-regulating () by a hairpin-RNA-mediated silencing approach, which resulted in only 5% residual transcript abundance.

Lignin engineering in field-grown poplar trees affects the endosphere bacterial microbiome.

Cinnamoyl-CoA reductase (CCR), an enzyme central to the lignin biosynthetic pathway, represents a promising biotechnological target to reduce lignin levels and to improve the commercial viability of lignocellulosic biomass. However, silencing of the CCR gene results in considerable flux changes of the general and monolignol-specific lignin pathways, ultimately leading to the accumulation of various extractable phenolic compounds in the xylem. Here, we evaluated host genotype-dependent effects of field-grown, CCR-down-regulated poplar trees (Populus tremula × Populus alba) on the bacterial rhizosphere microbiome and the endosphere microbiome, namely the microbiota present in roots, stems, and leaves.

PtaRHE1, a Populus tremula × Populus alba RING-H2 protein of the ATL family, has a regulatory role in secondary phloem fibre development.

REALLY INTERESTING NEW GENE (RING) proteins play important roles in the regulation of many processes by recognizing target proteins for ubiquitination. Previously, we have shown that the expression of PtaRHE1, encoding a Populus tremula × Populus alba RING-H2 protein with E3 ubiquitin ligase activity, is associated with tissues undergoing secondary growth. To further elucidate the role of PtaRHE1 in vascular tissues, we have undertaken a reverse genetic analysis in poplar.

Improved saccharification and ethanol yield from field-grown transgenic poplar deficient in cinnamoyl-CoA reductase.

Lignin is one of the main factors determining recalcitrance to enzymatic processing of lignocellulosic biomass. Poplars (Populus tremula x Populus alba) down-regulated for cinnamoyl-CoA reductase (CCR), the enzyme catalyzing the first step in the monolignol-specific branch of the lignin biosynthetic pathway, were grown in field trials in Belgium and France under short-rotation coppice culture. Wood samples were classified according to the intensity of the red xylem coloration typically associated with CCR down-regulation.

Lignin biosynthesis perturbations affect secondary cell wall composition and saccharification yield in Arabidopsis thaliana.

Background: Second-generation biofuels are generally produced from the polysaccharides in the lignocellulosic plant biomass, mainly cellulose. However, because cellulose is embedded in a matrix of other polysaccharides and lignin, its hydrolysis into the fermentable glucose is hampered. The senesced inflorescence stems of a set of 20 Arabidopsis thaliana mutants in 10 different genes of the lignin biosynthetic pathway were analyzed for cell wall composition and saccharification yield.

Plant cell wall profiling by fast maximum likelihood reconstruction (FMLR) and region-of-interest (ROI) segmentation of solution-state 2D 1H-13C NMR spectra.

Background: Interest in the detailed lignin and polysaccharide composition of plant cell walls has surged within the past decade partly as a result of biotechnology research aimed at converting biomass to biofuels. High-resolution, solution-state 2D 1H-13C HSQC NMR spectroscopy has proven to be an effective tool for rapid and reproducible fingerprinting of the numerous polysaccharides and lignin components in unfractionated plant cell wall materials, and is therefore a powerful tool for cell wall profiling based on our ability to simultaneously identify and comparatively quantify numerous components within spectra generated in a relatively short time. However, assigning peaks in new spectra, integrating them to provide relative component distributions, and producing color-assigned spectra, are all current bottlenecks to the routine use of such NMR profiling methods.

Breeding with rare defective alleles (BRDA): a natural Populus nigra HCT mutant with modified lignin as a case study.

Next-generation (NG) sequencing in a natural population of Populus nigra revealed a mutant with a premature stop codon in the gene encoding hydroxycinnamoyl-CoA : shikimate hydroxycinnamoyl transferase1 (HCT1), an essential enzyme in lignin biosynthesis. The lignin composition of P. nigra trees homozygous for the defective allele was compared with that of heterozygous trees and trees without the defective allele.

Potential of Arabidopsis systems biology to advance the biofuel field.

Plant biomass is a renewable and potentially sustainable resource for the production of liquid biofuels and a multitude of bio-based materials. To tailor plants for biofuel production, a powerful gene discovery program targeted to cell wall recalcitrance genes is needed. In parallel, a system is required that reveals the pleiotropic effects of gene modifications and that delivers the fundamental knowledge necessary for successful gene stacking.