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| 2. |
- Baison, J., et al.
(författare)
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Genetic control of tracheid properties in Norway spruce wood
- 2020
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Ingår i: Scientific Reports. - : Nature Research. - 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Through the use of genome-wide association studies (GWAS) mapping it is possible to establish the genetic basis of phenotypic trait variation. Our GWAS study presents the first such effort in Norway spruce (Picea abies (L). Karst.) for the traits related to wood tracheid characteristics. The study employed an exome capture genotyping approach that generated 178 101 Single Nucleotide Polymorphisms (SNPs) from 40 018 probes within a population of 517 Norway spruce mother trees. We applied a least absolute shrinkage and selection operator (LASSO) based association mapping method using a functional multi-locus mapping approach, with a stability selection probability method as the hypothesis testing approach to determine significant Quantitative Trait Loci (QTLs). The analysis has provided 30 significant associations, the majority of which show specific expression in wood-forming tissues or high ubiquitous expression, potentially controlling tracheids dimensions, their cell wall thickness and microfibril angle. Among the most promising candidates based on our results and prior information for other species are: Picea abies BIG GRAIN 2 (PabBG2) with a predicted function in auxin transport and sensitivity, and MA_373300g0010 encoding a protein similar to wall-associated receptor kinases, which were both associated with cell wall thickness. The results demonstrate feasibility of GWAS to identify novel candidate genes controlling industrially-relevant tracheid traits in Norway spruce. © 2020, The Author(s).
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| 3. |
- Banasiak, Alicja, et al.
(författare)
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Aspen Tension Wood Fibers Contain beta-(1 -> 4)-Galactans and Acidic Arabinogalactans Retained by Cellulose Microfibrils in Gelatinous Walls
- 2015
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Ingår i: Plant Physiology. - : Oxford University Press (OUP). - 0032-0889 .- 1532-2548. ; 169, s. 2048-2063
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Tidskriftsartikel (refereegranskat)abstract
- Contractile cell walls are found in various plant organs and tissues such as tendrils, contractile roots, and tension wood. The tension-generating mechanism is not known but is thought to involve special cell wall architecture. We previously postulated that tension could result from the entrapment of certain matrix polymers within cellulose microfibrils. As reported here, this hypothesis was corroborated by sequential extraction and analysis of cell wall polymers that are retained by cellulose microfibrils in tension wood and normal wood of hybrid aspen (Populus tremula x Populus tremuloides). beta-(1 -> 4)-Galactan and type II arabinogalactan were the main large matrix polymers retained by cellulose microfibrils that were specifically found in tension wood. Xyloglucan was detected mostly in oligomeric form in the alkali-labile fraction and was enriched in tension wood. beta-(1 -> 4)-Galactan and rhamnogalacturonan I backbone epitopes were localized in the gelatinous cell wall layer. Type II arabinogalactans retained by cellulose microfibrils had a higher content of (methyl) glucuronic acid and galactose in tension wood than in normal wood. Thus, beta-(1 -> 4)-galactan and a specialized form of type II arabinogalactan are trapped by cellulose microfibrils specifically in tension wood and, thus, are the main candidate polymers for the generation of tensional stresses by the entrapment mechanism. We also found high beta-galactosidase activity accompanying tension wood differentiation and propose a testable hypothesis that such activity might regulate galactan entrapment and, thus, mechanical properties of cell walls in tension wood.
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| 4. |
- Banasiak, Alicja, et al.
(författare)
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Glycoside hydrolase activities in cell walls of sclerenchyma cells in the inflorescence stems of Arabidopsis thaliana visualized in situ
- 2014
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Ingår i: PLANTS. - : MDPI AG. - 2223-7747. ; 3:4, s. 513-525
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Tidskriftsartikel (refereegranskat)abstract
- Techniques for in situ localization of gene products provide indispensable information for understanding biological function. In the case of enzymes, biological function is directly related to activity, and therefore, knowledge of activity patterns is central to understanding the molecular controls of plant development. We have previously developed a novel type of fluorogenic substrate for revealing glycoside hydrolase activity in planta, based on resorufin β-glycosides Here, we explore a wider range of such substrates to visualize glycoside hydrolase activities in Arabidopsis inflorescence stems in real time, especially highlighting distinct distribution patterns of these activities in the secondary cell walls of sclerenchyma cells. The results demonstrate that β-1,4-glucosidase, β-1,4-glucanase and β-1,4-galactosidase activities accompany secondary wall deposition. In contrast, xyloglucanase activity follows a different pattern, with the highest signal observed in mature cells, concentrated in the middle lamella. These data further the understanding of the process of cell wall deposition and function in sclerenchymatic tissues of plants.
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| 5. |
- Biswal, Ajaya K., et al.
(författare)
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Aspen pectate lyase PtxtPL1-27 mobilizes matrix polysaccharides from woody tissues and improves saccharification yield
- 2014
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Ingår i: Biotechnology for Biofuels. - : Springer Science and Business Media LLC. - 1754-6834. ; 7, s. 11-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Wood cell walls are rich in cellulose, hemicellulose and lignin. Hence, they are important sources of renewable biomass for producing energy and green chemicals. However, extracting desired constituents from wood efficiently poses significant challenges because these polymers are highly cross-linked in cell walls and are not easily accessible to enzymes and chemicals. Results: We show that aspen pectate lyase PL1-27, which degrades homogalacturonan and is expressed at the onset of secondary wall formation, can increase the solubility of wood matrix polysaccharides. Overexpression of this enzyme in aspen increased solubility of not only pectins but also xylans and other hemicelluloses, indicating that homogalacturonan limits the solubility of major wood cell wall components. Enzymatic saccharification of wood obtained from PL1-27-overexpressing trees gave higher yields of pentoses and hexoses than similar treatment of wood from wild-type trees, even after acid pretreatment. Conclusions: Thus, the modification of pectins may constitute an important biotechnological target for improved wood processing despite their low abundance in woody biomass.
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| 6. |
- Bygdell, Joakim, et al.
(författare)
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Protein expression in tension wood formation monitored at high tissue resolution in Populus
- 2017
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Ingår i: Journal of Experimental Botany. - : Oxford University Press. - 0022-0957 .- 1460-2431. ; 68:13, s. 3405-3417
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Tidskriftsartikel (refereegranskat)abstract
- Tension wood (TW) is a specialized tissue with contractile properties that is formed by the vascular cambium in response to gravitational stimuli. We quantitatively analysed the proteomes of Populus tremula cambium and its xylem cell derivatives in stems forming normal wood (NW) and TW to reveal the mechanisms underlying TW formation. Phloem-, cambium-, and wood-forming tissues were sampled by tangential cryosectioning and pooled into nine independent samples. The proteomes of TW and NW samples were similar in the phloem and cambium samples, but diverged early during xylogenesis, demonstrating that reprogramming is an integral part of TW formation. For example, 14-3-3, reactive oxygen species, ribosomal and ATPase complex proteins were found to be up-regulated at early stages of xylem differentiation during TW formation. At later stages of xylem differentiation, proteins involved in the biosynthesis of cellulose and enzymes involved in the biosynthesis of rhamnogalacturonan-I, rhamnogalacturonan-II, arabinogalactan-II and fasciclin-like arabinogalactan proteins were up-regulated in TW. Surprisingly, two isoforms of exostosin family proteins with putative xylan xylosyl transferase function and several lignin biosynthesis proteins were also up-regulated, even though xylan and lignin are known to be less abundant in TW than in NW. These data provided new insight into the processes behind TW formation.
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| 7. |
- Chen, Zhiqiang, et al.
(författare)
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Method for accurate fiber length determination from increment cores for large-scale population analyses in Norway spruce
- 2016
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Ingår i: Holzforschung. - : Walter de Gruyter GmbH. - 0018-3830 .- 1437-434X. ; 70:9, s. 829-838
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Tidskriftsartikel (refereegranskat)abstract
- Fiber (tracheid) length is an important trait targeted for genetic and silvicultural improvement. Such studies require large-scale non-destructive sampling, and accurate length determination. The standard procedure for non-destructive sampling is to collect increment cores, singularize their cells by maceration, measure them with optical analyzer and apply various corrections to suppress influence of non-fiber particles and cut fibers, as fibers are cut by the corer. The recently developed expectation-maximization method (EM) not only addresses the problem of non-fibers and cut fibers, but also corrects for the sampling bias. Here, the performance of the EM method has been evaluated by comparing it with length-weighing and squared length-weighing, both implemented in fiber analyzers, and with microscopy data for intact fibers, corrected for sampling bias, as the reference. This was done for 12-mm increment cores from 16 Norway spruce (Picea abies (L.) Karst) trees on fibers from rings 8-11 (counted from pith), representing juvenile wood of interest in breeding programs. The EM-estimates provided mean-fiber-lengths with bias of only +2.7% and low scatter. Length-weighing and length2-weighing gave biases of-7.3% and +9.3%, respectively, and larger scatter. The suggested EM approach constitutes a more accurate non-destructive method for fiber length (FL) determination, expected to be applicable also to other conifers.
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| 8. |
- Chen, Zhi-Qiang, et al.
(författare)
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Genetic analysis of fiber dimensions and their correlation with stem diameter and solid-wood properties in Norway spruce
- 2016
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Ingår i: Tree Genetics & Genomes. - : Springer Science and Business Media LLC. - 1614-2942 .- 1614-2950. ; 12:6
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Tidskriftsartikel (refereegranskat)abstract
- Adverse genetic correlations between growth traits and solid-wood, as well as fiber traits are a concern in conifer breeding programs. To evaluate the impact of selection for growth and solid-wood properties on fiber dimensions, we investigated the inheritance and efficiency of early selection for different wood-fiber traits and their correlations with stem diameter, wood density, modulus of elasticity (MOE), and microfibril angle (MFA) in Norway spruce (Picea abies L). The study was based on two large open-pollinated progeny trials established in southern Sweden in 1990 with material from 524 families comprising 5618 trees. Two increment cores were sampled from each tree. Radial variations from pith to bark were determined for rings 3–15 with SilviScan for fiber widths in the radial (RFW) and tangential (TFW) direction, fiber wall thickness (FWT), and fiber coarseness (FC). Fiber length (FL) was determined for rings 8–11. Heritabilities based on rings 8–11 using joint-site data were moderate to high (0.24–0.51) for all fiber-dimension traits. Heritabilities based on stem cross-sectional averages varied from 0.34 to 0.48 and reached a plateau at rings 6–9. The “age-age†genetic correlations for RFW, TFW, FWT, and FC cross-sectional averages at a particular age with cross-sectional averages at ring 15 reached 0.9 at rings 4–7. Our results indicated a moderate to high positive genetic correlation for density and MOE with FC and FWT, moderate and negative with RFW, and low with TFW and FL. Comparison of several selection scenarios indicated that the highest profitability is reached when diameter and MOE are considered jointly, in which case, the effect on any fiber dimension is negligible. Early selection was highly efficient from ring 5 for RFW and from rings 8–10 for TFW, FWT, and FC.
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| 9. |
- Chong, Sun-Li, et al.
(författare)
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Active fungal GH115 alpha-glucuronidase produced in Arabidopsis thaliana affects only the UX1-reactive glucuronate decorations on native glucuronoxylans
- 2015
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Ingår i: BMC Biotechnology. - : Springer Science and Business Media LLC. - 1472-6750. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Background: Expressing microbial polysaccharide-modifying enzymes in plants is an attractive approach to custom tailor plant lignocellulose and to study the importance of wall structures to plant development. Expression of alpha-glucuronidases in plants to modify the structures of glucuronoxylans has not been yet attempted. Glycoside hydrolase (GH) family 115 alpha-glucuronidases cleave the internal alpha-D-(4-O-methyl)glucopyranosyluronic acid ((Me)GlcA) from xylans or xylooligosaccharides. In this work, a GH115 alpha-glucuronidase from Schizophyllum commune, ScAGU115, was expressed in Arabidopsis thaliana and targeted to apoplast. The transgene effects on native xylans' structures, plant development, and lignocellulose saccharification were evaluated and compared to those of knocked out glucuronyltransferases AtGUX1 and AtGUX2.Results: The ScAGU115 extracted from cell walls of Arabidopsis was active on the internally substituted aldopentaouronic acid (XUXX). The transgenic plants did not show any change in growth or in lignocellulose saccharification. The cell wall (Me)GlcA and other non-cellulosic sugars, as well as the lignin content, remained unchanged. In contrast, the gux1gux2 double mutant showed a 70% decrease in (Me)GlcA to xylose molar ratio, and, interestingly, a 60% increase in the xylose content. Whereas ScAGU115-expressing plants exhibited a decreased signal in native secondary walls from the monoclonal antibody UX1 that recognizes (Me)GlcA on non-acetylated xylan, the signal was not affected after wall deacetylation. In contrast, gux1gux2 mutant was lacking UX1 signals in both native and deacetylated cell walls. This indicates that acetyl substitution on the xylopyranosyl residue carrying (Me)GlcA or on the neighboring xylopyranosyl residues may restrict post-synthetic modification of xylans by ScAGU115 in planta.Conclusions: Active GH115 alpha-glucuronidase has been produced for the first time in plants. The cell wall-targeted ScAGU115 was shown to affect those glucuronate substitutions of xylan, which are accessible to UX1 antibody and constitute a small fraction in Arabidopsis, whereas majority of (Me)GlcA substitutions were resistant, most likely due to the shielding by acetyl groups. Plants expressing ScAGU115 did not show any defects under laboratory conditions indicating that the UX1 epitope of xylan is not essential under these conditions. Moreover the removal of the UX1 xylan epitope does not affect lignocellulose saccharification.
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