| 1. |
- Baison, John, et al.
(författare)
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Genome-Wide Association Study (GWAS) identified novel candidate loci affecting wood formation in Norway spruce
- 2019
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Ingår i: The Plant Journal. - : Wiley. - 0960-7412 .- 1365-313X. ; 100:1, s. 83-100
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Tidskriftsartikel (refereegranskat)abstract
- Norway spruce is a boreal forest tree species of significant ecological and economic importance. Hence there is a strong imperative to dissect the genetics underlying important wood quality traits in the species. We performed a functional Genome-Wide Association Study (GWAS) of 17 wood traits in Norway spruce using 178101 single-nucleotide polymorphisms (SNPs) generated from exome genotyping of 517 mother trees. The wood traits were defined using functional modelling of wood properties across annual growth rings.We applied a LASSO based association mapping method using a functional multi-locus mapping approach that utilizes latent traits, with a stability selection probability method as the hypothesis testing approach to determine significant Quantitative Trait Loci (QTLs). The analysis provided 52 significant SNPs from 39 candidate genes, including genes previously implicated in wood formation and tree growth in spruce and other species. Our study represents a multi-locus GWAS for complex wood traits in Norway spruce. The results advance our understanding of the genetics influencing wood traits and identifies candidate genes for future functional studies.
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| 2. |
- Baison, John, et al.
(författare)
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Genome-wide association study identified novel candidate loci affecting wood formation in Norway spruce
- 2019
-
Ingår i: The Plant Journal. - : John Wiley & Sons. - 0960-7412 .- 1365-313X. ; 100:1, s. 83-100
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Tidskriftsartikel (refereegranskat)abstract
- Norway spruce is a boreal forest tree species of significant ecological and economic importance. Hence there is a strong imperative to dissect the genetics underlying important wood quality traits in the species. We performed a functional genome-wide association study (GWAS) of 17 wood traits in Norway spruce using 178 101 single nucleotide polymorphisms (SNPs) generated from exome genotyping of 517 mother trees. The wood traits were defined using functional modelling of wood properties across annual growth rings. We applied a Least Absolute Shrinkage and Selection Operator (LASSO-based) association mapping method using a functional multilocus mapping approach that utilizes latent traits, with a stability selection probability method as the hypothesis testing approach to determine a significant quantitative trait locus. The analysis provided 52 significant SNPs from 39 candidate genes, including genes previously implicated in wood formation and tree growth in spruce and other species. Our study represents a multilocus GWAS for complex wood traits in Norway spruce. The results advance our understanding of the genetics influencing wood traits and identifies candidate genes for future functional studies.
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| 3. |
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| 4. |
- Jonasson, Simon, et al.
(författare)
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Mechanical-chemical nanofiber extractability of woodwith variable ultrastructure and composition throughone-pot oxidative pretreatments
- 2019
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Ingår i: 6<sup>th</sup> EPNOE International Polysaccharide Conference. - : European Polysaccharide Network of Excellence (EPNOE). ; , s. 114-114
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Konferensbidrag (refereegranskat)abstract
- Isolation of high value nanofibers from lignocellulosic feedstocks is a costly and resource intensive process. This stems from the complex structure of the raw material which contains hierarchical crystalline cellulose within hydrophobic lignin layers. This inherent structure makes inquiries regarding suitability of a certain lignocellulose for nanofibrillation difficult. Further nuances are present due to the common usage of both mechanical and chemical processing, often using pre-delignified wood as starting material.In this study we look at how the isolation of nanofibers is a↵ected by inherent wood properties by nanofibrillating wood from trees that has been physically stimulated to produce biomass with higher cellulose/lignin ratio and a different cell wall structure. Cryocrushed samples have been processed with i) mechanical, ii) chemical and iii) mechanical-chemical treatments, where (one-pot) direct TEMPO-catalyzed oxidation with different severity and high-pressure homogenization serve as controlled chemical and mechanical factors, respectively.The nanofibers have been characterized in suspension according to traditional procedures regarding degree of fibrillation, and then made into dense nanopapers for mechanical characterization. The material behavior is discussed in relation to the structure of the initial biomass and corresponding fibrillation efficiency. The results are presented in terms of both mechanical disintegration and chemical (carboxylation) derivatization.
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| 5. |
- Mahboubi, Miramirhossein, et al.
(författare)
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C-13 Tracking after (CO2)-C-13 Supply Revealed Diurnal Patterns of Wood Formation in Aspen
- 2015
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Ingår i: Plant Physiology. - : Oxford University Press (OUP). - 0032-0889 .- 1532-2548. ; 168, s. 478-489
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Tidskriftsartikel (refereegranskat)abstract
- Wood of trees is formed from carbon assimilated in the photosynthetic tissues. Determining the temporal dynamics of carbon assimilation, subsequent transport into developing wood, and incorporation to cell walls would further our understanding of wood formation in particular and tree growth in general. To investigate these questions, we designed a (CO2)-C-13 labeling system to study carbon transport and incorporation to developing wood of hybrid aspen (Populus tremula 3 tremuloides). Tracking of C-13 incorporation to wood over a time course using nuclear magnetic resonance spectroscopy revealed diurnal patterns in wood cell wall biosynthesis. The dark period had a differential effect on C-13 incorporation to lignin and cell wall carbohydrates. No C-13 was incorporated into aromatic amino acids of cell wall proteins in the dark, suggesting that cell wall protein biosynthesis ceased during the night. The results show previously unrecognized temporal patterns in wood cell wall biosynthesis, suggest diurnal cycle as a possible cue in the regulation of carbon incorporation to wood, and establish a unique C-13 labeling method for the analysis of wood formation and secondary growth in trees.
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| 6. |
- Mahboubi, Miramirhossein, et al.
(författare)
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Sucrose transport and carbon fluxes during wood formation
- 2018
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Ingår i: Physiologia Plantarum. - : Wiley. - 0031-9317 .- 1399-3054. ; 164, s. 67-81
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Tidskriftsartikel (refereegranskat)abstract
- Wood biosynthesis defines the chemical and structural properties of wood. The metabolic pathways that produce the precursors of wood cell wall polymers have a central role in defining wood properties. To make rational design of wood properties feasible, we need not only to understand the cell wall biosynthetic machinery, but also how sucrose transport and metabolism in developing wood connect to cell wall biosynthesis and how they respond to genetic and environmental cues. Here, we review the current understanding of the sucrose transport and primary metabolism pathways leading to the precursors of cell wall biosynthesis in woody plant tissues. We present both old, persistent questions and new emerging themes with a focus on wood formation in trees and draw upon evidence from the xylem tissues of herbaceous plants when it is relevant.
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| 7. |
- Rende, Umut, et al.
(författare)
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Cytosolic invertase contributes to the supply of substrate for cellulose biosynthesis in developing wood
- 2017
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Ingår i: New Phytologist. - : Wiley-Blackwell. - 0028-646X .- 1469-8137. ; 214:2, s. 796-807
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Tidskriftsartikel (refereegranskat)abstract
- Carbon for cellulose biosynthesis is derived from sucrose. Cellulose is synthesized from uridine 5'-diphosphoglucose (UDP-glucose), but the enzyme(s) responsible for the initial sucrose cleavage and the source of UDP-glucose for cellulose biosynthesis in developing wood have not been defined. We investigated the role of CYTOSOLIC INVERTASEs (CINs) during wood formation in hybrid aspen (Populus tremula × tremuloides) and characterized transgenic lines with reduced CIN activity during secondary cell wall biosynthesis. Suppression of CIN activity by 38–55% led to a 9–13% reduction in crystalline cellulose. The changes in cellulose were reflected in reduced diameter of acid-insoluble cellulose microfibrils and increased glucose release from wood upon enzymatic digestion of cellulose. Reduced CIN activity decreased the amount of the cellulose biosynthesis precursor UDP-glucose in developing wood, pointing to the likely cause of the cellulose phenotype. The findings suggest that CIN activity has an important role in the cellulose biosynthesis of trees, and indicate that cellulose biosynthesis in wood relies on a quantifiable UDP-glucose pool. The results also introduce a concept of altering cellulose microfibril properties by modifying substrate supply to cellulose biosynthesis.
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| 8. |
- Rende, Umut, et al.
(författare)
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Two-step derivatization for determination of sugar phosphates in plants by combined reversed phase chromatography/tandem mass spectrometry
- 2019
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Ingår i: Plant Methods. - : Springer Science and Business Media LLC. - 1746-4811. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Background Sugar phosphates are important intermediates of central carbon metabolism in biological systems, with roles in glycolysis, the pentose-phosphate pathway, tricarboxylic acid (TCA) cycle, and many other biosynthesis pathways. Understanding central carbon metabolism requires a simple, robust and comprehensive analytical method. However, sugar phosphates are notoriously difficult to analyze by traditional reversed phase liquid chromatography. Results Here, we show a two-step derivatization of sugar phosphates by methoxylamine and propionic acid anhydride after chloroform/methanol (3:7) extraction from Populus leaf and developing wood that improves separation, identification and quantification of sugar phosphates by ultra high performance liquid chromatography-electrospray ionization-mass spectrometry (UHPLC-ESI-MS). Standard curves of authentic sugar phosphates were generated for concentrations from pg to ng/mu l with a correlation coefficient R-2 > 0.99. The method showed high sensitivity and repeatability with relative standard deviation (RSD) < 20% based on repeated extraction, derivatization and detection. The analytical accuracy for Populus leaf extracts, determined by a two-level spiking approach of selected metabolites, was 79-107%. Conclusion The results show the reliability of combined reversed phase liquid chromatography-tandem mass spectrometry for sugar phosphate analysis and demonstrate the presence of two unknown sugar phosphates in Populus extracts.
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| 9. |
- Roach, Melissa, et al.
(författare)
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Spatially resolved metabolic analysis reveals a central role for transcriptional control in carbon allocation to wood
- 2017
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Ingår i: Journal of Experimental Botany. - : Oxford University Press (OUP). - 0022-0957 .- 1460-2431. ; 68, s. 3529-3539
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Tidskriftsartikel (refereegranskat)abstract
- The contribution of transcriptional and post-transcriptional regulation to modifying carbon allocation to developing wood of trees is not well defined. To clarify the role of transcriptional regulation, the enzyme activity patterns of eight central primary metabolism enzymes across phloem, cambium, and developing wood of aspen (Populus tremula L.) were compared with transcript levels obtained by RNA sequencing of sequential stem sections from the same trees. Enzymes were selected on the basis of their importance in sugar metabolism and in linking primary metabolism to lignin biosynthesis. Existing enzyme assays were adapted to allow measurements from similar to 1 mm(3) sections of dissected stem tissue. These experiments provided high spatial resolution of enzyme activity changes across different stages of wood development, and identified the gene transcripts probably responsible for these changes. In most cases, there was a clear positive relationship between transcripts and enzyme activity. During secondary cell wall formation, the increases in transcript levels and enzyme activities also matched with increased levels of glucose, fructose, hexose phosphates, and UDP-glucose, emphasizing an important role for transcriptional regulation in carbon allocation to developing aspen wood. These observations corroborate the efforts to increase carbon allocation to wood by engineering gene regulatory networks.
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| 10. |
- Schneider, Rene, et al.
(författare)
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Two Complementary Mechanisms Underpin Cell Wall Patterning during Xylem Vessel Development
- 2017
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Ingår i: The Plant Cell. - : Oxford University Press (OUP). - 1040-4651 .- 1532-298X. ; 29:10, s. 2433-2449
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Tidskriftsartikel (refereegranskat)abstract
- The evolution of the plant vasculature was essential for the emergence of terrestrial life. Xylem vessels are solute-transporting elements in the vasculature that possess secondary wall thickenings deposited in intricate patterns. Evenly dispersed microtubule (MT) bands support the formation of these wall thickenings, but how the MTs direct cell wall synthesis during this process remains largely unknown. Cellulose is the major secondary wall constituent and is synthesized by plasma membrane-localized cellulose synthases (CesAs) whose catalytic activity propels them through the membrane. We show that the protein CELLULOSE SYNTHASE INTERACTING1 (CSI1)/POM2 is necessary to align the secondary wall CesAs and MTs during the initial phase of xylem vessel development in Arabidopsis thaliana and rice (Oryza sativa). Surprisingly, these MT-driven patterns successively become imprinted and sufficient to sustain the continued progression of wall thickening in the absence of MTs and CSI1/POM2 function. Hence, two complementary principles underpin wall patterning during xylem vessel development.
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