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Chaudhari AA, Sharma AM, Rastogi L, Dewangan BP, Sharma R, Singh D, Sah RK, Das S, Bhattacharjee S, Mellerowicz EJ, Pawar PAM. Modifying lignin composition and xylan O-acetylation induces changes in cell wall composition, extractability, and digestibility. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:73. [PMID: 38822388 PMCID: PMC11141020 DOI: 10.1186/s13068-024-02513-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Accepted: 05/01/2024] [Indexed: 06/03/2024]
Abstract
BACKGROUND Lignin and xylan are important determinants of cell wall structure and lignocellulosic biomass digestibility. Genetic manipulations that individually modify either lignin or xylan structure improve polysaccharide digestibility. However, the effects of their simultaneous modifications have not been explored in a similar context. Here, both individual and combinatorial modification in xylan and lignin was studied by analysing the effect on plant cell wall properties, biotic stress responses and integrity sensing. RESULTS Arabidopsis plant co-harbouring mutation in FERULATE 5-HYDROXYLASE (F5H) and overexpressing Aspergillus niger acetyl xylan esterase (35S:AnAXE1) were generated and displayed normal growth attributes with intact xylem architecture. This fah1-2/35S:AnAXE1 cross was named as hyper G lignin and hypoacetylated (HrGHypAc) line. The HrGHypAc plants showed increased crystalline cellulose content with enhanced digestibility after chemical and enzymatic pre-treatment. Moreover, both parents and HrGHypAc without and after pre-treating with glucuronyl esterase and alpha glucuronidase exhibited an increase in xylose release after xylanase digestion as compared to wild type. The de-pectinated fraction in HrGHypAc displayed elevated levels of xylan and cellulose. Furthermore, the transcriptomic analysis revealed differential expression in cell wall biosynthetic, transcription factors and wall-associated kinases genes implying the role of lignin and xylan modification on cellular regulatory processes. CONCLUSIONS Simultaneous modification in xylan and lignin enhances cellulose content with improved saccharification efficiency. These modifications loosen cell wall complexity and hence resulted in enhanced xylose and xylobiose release with or without pretreatment after xylanase digestion in both parent and HrGHypAc. This study also revealed that the disruption of xylan and lignin structure is possible without compromising either growth and development or defense responses against Pseudomonas syringae infection.
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Affiliation(s)
- Aniket Anant Chaudhari
- Regional Centre for Biotechnology, Laboratory of Plant Cell Wall Biology, NCR Biotech Science, Cluster 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad-121001, Haryana, India
| | - Anant Mohan Sharma
- Regional Centre for Biotechnology, Laboratory of Plant Cell Wall Biology, NCR Biotech Science, Cluster 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad-121001, Haryana, India
| | - Lavi Rastogi
- Regional Centre for Biotechnology, Laboratory of Plant Cell Wall Biology, NCR Biotech Science, Cluster 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad-121001, Haryana, India
| | - Bhagwat Prasad Dewangan
- Regional Centre for Biotechnology, Laboratory of Plant Cell Wall Biology, NCR Biotech Science, Cluster 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad-121001, Haryana, India
| | - Raunak Sharma
- Regional Centre for Biotechnology, Laboratory of Plant Cell Wall Biology, NCR Biotech Science, Cluster 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad-121001, Haryana, India
| | - Deepika Singh
- Regional Centre for Biotechnology, Laboratory of Plant Cell Wall Biology, NCR Biotech Science, Cluster 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad-121001, Haryana, India
| | - Rajan Kumar Sah
- Regional Centre for Biotechnology, Laboratory of Plant Cell Wall Biology, NCR Biotech Science, Cluster 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad-121001, Haryana, India
| | - Shouvik Das
- Regional Centre for Biotechnology, Laboratory of Plant Cell Wall Biology, NCR Biotech Science, Cluster 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad-121001, Haryana, India
| | - Saikat Bhattacharjee
- Regional Centre for Biotechnology, Laboratory of Plant Cell Wall Biology, NCR Biotech Science, Cluster 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad-121001, Haryana, India
| | - Ewa J Mellerowicz
- Department of Forest Genetics and Plant Physiology, Umea Plant Science Centre, Swedish University of Agricultural Sciences, Umea, Sweden
| | - Prashant Anupama-Mohan Pawar
- Regional Centre for Biotechnology, Laboratory of Plant Cell Wall Biology, NCR Biotech Science, Cluster 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad-121001, Haryana, India.
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2
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Zhu Y, Li L. Wood of trees: Cellular structure, molecular formation, and genetic engineering. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2024; 66:443-467. [PMID: 38032010 DOI: 10.1111/jipb.13589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 11/28/2023] [Indexed: 12/01/2023]
Abstract
Wood is an invaluable asset to human society due to its renewable nature, making it suitable for both sustainable energy production and material manufacturing. Additionally, wood derived from forest trees plays a crucial role in sequestering a significant portion of the carbon dioxide fixed during photosynthesis by terrestrial plants. Nevertheless, with the expansion of the global population and ongoing industrialization, forest coverage has been substantially decreased, resulting in significant challenges for wood production and supply. Wood production practices have changed away from natural forests toward plantation forests. Thus, understanding the underlying genetic mechanisms of wood formation is the foundation for developing high-quality, fast-growing plantation trees. Breeding ideal forest trees for wood production using genetic technologies has attracted the interest of many. Tremendous studies have been carried out in recent years on the molecular, genetic, and cell-biological mechanisms of wood formation, and considerable progress and findings have been achieved. These studies and findings indicate enormous possibilities and prospects for tree improvement. This review will outline and assess the cellular and molecular mechanisms of wood formation, as well as studies on genetically improving forest trees, and address future development prospects.
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Affiliation(s)
- Yingying Zhu
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems and College of Ecology, Lanzhou University, Lanzhou, 730000, China
| | - Laigeng Li
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
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3
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Li W, Lin YCJ, Chen YL, Zhou C, Li S, De Ridder N, Oliveira DM, Zhang L, Zhang B, Wang JP, Xu C, Fu X, Luo K, Wu AM, Demura T, Lu MZ, Zhou Y, Li L, Umezawa T, Boerjan W, Chiang VL. Woody plant cell walls: Fundamentals and utilization. MOLECULAR PLANT 2024; 17:112-140. [PMID: 38102833 DOI: 10.1016/j.molp.2023.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/12/2023] [Accepted: 12/12/2023] [Indexed: 12/17/2023]
Abstract
Cell walls in plants, particularly forest trees, are the major carbon sink of the terrestrial ecosystem. Chemical and biosynthetic features of plant cell walls were revealed early on, focusing mostly on herbaceous model species. Recent developments in genomics, transcriptomics, epigenomics, transgenesis, and associated analytical techniques are enabling novel insights into formation of woody cell walls. Here, we review multilevel regulation of cell wall biosynthesis in forest tree species. We highlight current approaches to engineering cell walls as potential feedstock for materials and energy and survey reported field tests of such engineered transgenic trees. We outline opportunities and challenges in future research to better understand cell type biogenesis for more efficient wood cell wall modification and utilization for biomaterials or for enhanced carbon capture and storage.
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Affiliation(s)
- Wei Li
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China
| | | | - Ying-Lan Chen
- Department of Biotechnology and Bioindustry Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan, China
| | - Chenguang Zhou
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China
| | - Shuang Li
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China
| | - Nette De Ridder
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, 9052 Ghent, Belgium; VIB Center for Plant Systems Biology, Technologiepark 71, 9052 Ghent, Belgium
| | - Dyoni M Oliveira
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, 9052 Ghent, Belgium; VIB Center for Plant Systems Biology, Technologiepark 71, 9052 Ghent, Belgium
| | - Lanjun Zhang
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Baocai Zhang
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jack P Wang
- Forest Biotechnology Group, Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27695, USA
| | - Changzheng Xu
- Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Integrative Science Center of Germplasm Creation, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Xiaokang Fu
- Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Integrative Science Center of Germplasm Creation, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Keming Luo
- Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Integrative Science Center of Germplasm Creation, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Ai-Min Wu
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architectures, South China Agricultural University, Guangzhou 510642, China
| | - Taku Demura
- Center for Digital Green-innovation, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Meng-Zhu Lu
- State Key Laboratory of Subtropical Silviculture, College of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China
| | - Yihua Zhou
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Laigeng Li
- CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
| | - Toshiaki Umezawa
- Laboratory of Metabolic Science of Forest Plants and Microorganisms, Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Wout Boerjan
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, 9052 Ghent, Belgium; VIB Center for Plant Systems Biology, Technologiepark 71, 9052 Ghent, Belgium
| | - Vincent L Chiang
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China; Forest Biotechnology Group, Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27695, USA.
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4
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Derba-Maceluch M, Sivan P, Donev EN, Gandla ML, Yassin Z, Vaasan R, Heinonen E, Andersson S, Amini F, Scheepers G, Johansson U, Vilaplana FJ, Albrectsen BR, Hertzberg M, Jönsson LJ, Mellerowicz EJ. Impact of xylan on field productivity and wood saccharification properties in aspen. FRONTIERS IN PLANT SCIENCE 2023; 14:1218302. [PMID: 37528966 PMCID: PMC10389764 DOI: 10.3389/fpls.2023.1218302] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 06/27/2023] [Indexed: 08/03/2023]
Abstract
Xylan that comprises roughly 25% of hardwood biomass is undesirable in biorefinery applications involving saccharification and fermentation. Efforts to reduce xylan levels have therefore been made in many species, usually resulting in improved saccharification. However, such modified plants have not yet been tested under field conditions. Here we evaluate the field performance of transgenic hybrid aspen lines with reduced xylan levels and assess their usefulness as short-rotation feedstocks for biorefineries. Three types of transgenic lines were tested in four-year field tests with RNAi constructs targeting either Populus GT43 clades B and C (GT43BC) corresponding to Arabidopsis clades IRX9 and IRX14, respectively, involved in xylan backbone biosynthesis, GATL1.1 corresponding to AtGALT1 involved in xylan reducing end sequence biosynthesis, or ASPR1 encoding an atypical aspartate protease. Their productivity, wood quality traits, and saccharification efficiency were analyzed. The only lines differing significantly from the wild type with respect to growth and biotic stress resistance were the ASPR1 lines, whose stems were roughly 10% shorter and narrower and leaves showed increased arthropod damage. GT43BC lines exhibited no growth advantage in the field despite their superior growth in greenhouse experiments. Wood from the ASPR1 and GT43BC lines had slightly reduced density due to thinner cell walls and, in the case of ASPR1, larger cell diameters. The xylan was less extractable by alkali but more hydrolysable by acid, had increased glucuronosylation, and its content was reduced in all three types of transgenic lines. The hemicellulose size distribution in the GALT1.1 and ASPR1 lines was skewed towards higher molecular mass compared to the wild type. These results provide experimental evidence that GATL1.1 functions in xylan biosynthesis and suggest that ASPR1 may regulate this process. In saccharification without pretreatment, lines of all three constructs provided 8-11% higher average glucose yields than wild-type plants. In saccharification with acid pretreatment, the GT43BC construct provided a 10% yield increase on average. The best transgenic lines of each construct are thus predicted to modestly outperform the wild type in terms of glucose yields per hectare. The field evaluation of transgenic xylan-reduced aspen represents an important step towards more productive feedstocks for biorefineries.
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Affiliation(s)
- Marta Derba-Maceluch
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Pramod Sivan
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, Sweden
- Division of Glycoscience, Department of Chemistry, KTH Royal Institute of Technology, AlbaNova University Centre, Stockholm, Sweden
| | - Evgeniy N. Donev
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, Sweden
| | | | - Zakiya Yassin
- Enhet Produktionssystem och Material, RISE Research Institutes of Sweden, Växjö, Sweden
| | - Rakhesh Vaasan
- Division of Glycoscience, Department of Chemistry, KTH Royal Institute of Technology, AlbaNova University Centre, Stockholm, Sweden
| | - Emilia Heinonen
- Division of Glycoscience, Department of Chemistry, KTH Royal Institute of Technology, AlbaNova University Centre, Stockholm, Sweden
- Wallenberg Wood Science Centre (WWSC), KTH Royal Institute of Technology, Stockholm, Sweden
| | - Sanna Andersson
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Fariba Amini
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umea, Sweden
- Biology Department, Faculty of Science, Arak University, Arak, Iran
| | - Gerhard Scheepers
- Enhet Produktionssystem och Material, RISE Research Institutes of Sweden, Växjö, Sweden
| | - Ulf Johansson
- Tönnersjöheden Experimental Forest, Swedish University of Agricultural Sciences, Simlångsdalen, Sweden
| | - Francisco J. Vilaplana
- Division of Glycoscience, Department of Chemistry, KTH Royal Institute of Technology, AlbaNova University Centre, Stockholm, Sweden
- Wallenberg Wood Science Centre (WWSC), KTH Royal Institute of Technology, Stockholm, Sweden
| | | | | | | | - Ewa J. Mellerowicz
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, Sweden
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5
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Donev EN, Derba‐Maceluch M, Yassin Z, Gandla ML, Pramod S, Heinonen E, Kumar V, Scheepers G, Vilaplana F, Johansson U, Hertzberg M, Sundberg B, Winestrand S, Hörnberg A, Alriksson B, Jönsson LJ, Mellerowicz EJ. Field testing of transgenic aspen from large greenhouse screening identifies unexpected winners. PLANT BIOTECHNOLOGY JOURNAL 2023; 21:1005-1021. [PMID: 36668687 PMCID: PMC10106850 DOI: 10.1111/pbi.14012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 11/30/2022] [Accepted: 12/29/2022] [Indexed: 05/04/2023]
Abstract
Trees constitute promising renewable feedstocks for biorefinery using biochemical conversion, but their recalcitrance restricts their attractiveness for the industry. To obtain trees with reduced recalcitrance, large-scale genetic engineering experiments were performed in hybrid aspen blindly targeting genes expressed during wood formation and 32 lines representing seven constructs were selected for characterization in the field. Here we report phenotypes of five-year old trees considering 49 traits related to growth and wood properties. The best performing construct considering growth and glucose yield in saccharification with acid pretreatment had suppressed expression of the gene encoding an uncharacterized 2-oxoglutarate-dependent dioxygenase (2OGD). It showed minor changes in wood chemistry but increased nanoporosity and glucose conversion. Suppressed levels of SUCROSE SYNTHASE, (SuSy), CINNAMATE 4-HYDROXYLASE (C4H) and increased levels of GTPase activating protein for ADP-ribosylation factor ZAC led to significant growth reductions and anatomical abnormalities. However, C4H and SuSy constructs greatly improved glucose yields in saccharification without and with pretreatment, respectively. Traits associated with high glucose yields were different for saccharification with and without pretreatment. While carbohydrates, phenolics and tension wood contents positively impacted the yields without pretreatment and growth, lignin content and S/G ratio were negative factors, the yields with pretreatment positively correlated with S lignin and negatively with carbohydrate contents. The genotypes with high glucose yields had increased nanoporosity and mGlcA/Xyl ratio, and some had shorter polymers extractable with subcritical water compared to wild-type. The pilot-scale industrial-like pretreatment of best-performing 2OGD construct confirmed its superior sugar yields, supporting our strategy.
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Affiliation(s)
- Evgeniy N. Donev
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science CentreSwedish University of Agricultural SciencesUmeåSweden
| | - Marta Derba‐Maceluch
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science CentreSwedish University of Agricultural SciencesUmeåSweden
| | - Zakiya Yassin
- Enhet Produktionssystem och MaterialRISE Research Institutes of SwedenVäxjöSweden
| | | | - Sivan Pramod
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science CentreSwedish University of Agricultural SciencesUmeåSweden
- Division of Glycoscience, Department of ChemistryKTH Royal Institute of Technology, AlbaNova University CentreStockholmSweden
| | - Emilia Heinonen
- Division of Glycoscience, Department of ChemistryKTH Royal Institute of Technology, AlbaNova University CentreStockholmSweden
- Wallenberg Wood Science Centre (WWSC)KTH Royal Institute of TechnologyStockholmSweden
| | - Vikash Kumar
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science CentreSwedish University of Agricultural SciencesUmeåSweden
| | - Gerhard Scheepers
- Enhet Produktionssystem och MaterialRISE Research Institutes of SwedenVäxjöSweden
| | - Francisco Vilaplana
- Division of Glycoscience, Department of ChemistryKTH Royal Institute of Technology, AlbaNova University CentreStockholmSweden
- Wallenberg Wood Science Centre (WWSC)KTH Royal Institute of TechnologyStockholmSweden
| | - Ulf Johansson
- Tönnersjöheden Experimental ForestSwedish University of Agricultural SciencesSimlångsdalenSweden
| | | | - Björn Sundberg
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science CentreSwedish University of Agricultural SciencesUmeåSweden
| | | | | | | | | | - Ewa J. Mellerowicz
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science CentreSwedish University of Agricultural SciencesUmeåSweden
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6
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Robinson KM, Möller L, Bhalerao RP, Hertzberg M, Nilsson O, Jansson S. Variation in non-target traits in genetically modified hybrid aspens does not exceed natural variation. N Biotechnol 2021; 64:27-36. [PMID: 34048978 DOI: 10.1016/j.nbt.2021.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 05/20/2021] [Accepted: 05/22/2021] [Indexed: 11/18/2022]
Abstract
Genetically modified hybrid aspens (Populus tremula L. x P. tremuloides Michx.), selected for increased growth under controlled conditions, have been grown in highly replicated field trials to evaluate how the target trait (growth) translated to natural conditions. Moreover, the variation was compared among genotypes of ecologically important non-target traits: number of shoots, bud set, pathogen infection, amount of insect herbivory, composition of the insect herbivore community and flower bud induction. This variation was compared with the variation in a population of randomly selected natural accessions of P. tremula grown in common garden trials, to estimate how the "unintended variation" present in transgenic trees, which in the future may be commercialized, compares with natural variation. The natural variation in the traits was found to be typically significantly greater. The data suggest that when authorities evaluate the potential risks associated with a field experiment or commercial introduction of transgenic trees, risk evaluation should focus on target traits and that unintentional variation in non-target traits is of less concern.
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Affiliation(s)
- Kathryn M Robinson
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, 901 87, Umeå, Sweden.
| | - Linus Möller
- SweTree Technologies AB, P.O Box 4095, 904 03, Umeå, Sweden.
| | - Rishikesh P Bhalerao
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden.
| | | | - Ove Nilsson
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden.
| | - Stefan Jansson
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, 901 87, Umeå, Sweden.
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7
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Pramod S, Gandla ML, Derba-Maceluch M, Jönsson LJ, Mellerowicz EJ, Winestrand S. Saccharification Potential of Transgenic Greenhouse- and Field-Grown Aspen Engineered for Reduced Xylan Acetylation. FRONTIERS IN PLANT SCIENCE 2021; 12:704960. [PMID: 34557213 PMCID: PMC8454504 DOI: 10.3389/fpls.2021.704960] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 07/22/2021] [Indexed: 05/20/2023]
Abstract
High acetylation of xylan in hardwoods decreases their value as biorefinery feedstocks. To counter this problem, we have constitutively suppressed RWA genes encoding acetyl-CoA transporters using the 35S promoter, or constitutively and wood-specifically (using the WP promoter) expressed fungal acetyl xylan esterases of families CE1 (AnAXE1) and CE5 (HjAXE), to reduce acetylation in hybrid aspen. All these transformations improved the saccharification of wood from greenhouse-grown trees. Here, we describe the chemical properties and saccharification potential of the resulting lines grown in a five-year field trial, and one type of them (WP:AnAXE1) in greenhouse conditions. Chemically, the lignocellulose of the field- and greenhouse-field-grown plants slightly differed, but the reductions in acetylation and saccharification improvement of engineered trees were largely maintained in the field. The main novel phenotypic observation in the field was higher lignification in lines with the WP promoter than those with the 35S promoter. Following growth in the field, saccharification glucose yields were higher from most transformed lines than from wild-type (WT) plants with no pretreatment, but there was no improvement in saccharification with acid pretreatment. Thus, acid pretreatment removes most recalcitrance caused by acetylation. We found a complex relationship between acetylation and glucose yields in saccharification without pretreatment, suggesting that other variables, for example, the acetylation pattern, affect recalcitrance. Bigger gains in glucose yields were observed in lines with the 35S promoter than in those with the WP promoter, possibly due to their lower lignin content. However, better lignocellulose saccharification of these lines was offset by a growth penalty and their glucose yield per tree was lower. In a comparison of the best lines with each construct, WP:AnAXE1 provided the highest glucose yield per tree from saccharification, with and without pretreatment, WP:HjAXE yields were similar to those of WT plants, and yields of lines with other constructs were lower. These results show that lignocellulose properties of field-grown trees can be improved by reducing cell wall acetylation using various approaches, but some affect productivity in the field. Thus, better understanding of molecular and physiological consequences of deacetylation is needed to obtain quantitatively better results.
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Affiliation(s)
- Sivan Pramod
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, Umeå, Sweden
| | | | - Marta Derba-Maceluch
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, Umeå, Sweden
| | | | - Ewa J. Mellerowicz
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, Umeå, Sweden
- *Correspondence: Ewa J. Mellerowicz,
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8
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Qaseem MF, Wu AM. Balanced Xylan Acetylation is the Key Regulator of Plant Growth and Development, and Cell Wall Structure and for Industrial Utilization. Int J Mol Sci 2020; 21:ijms21217875. [PMID: 33114198 PMCID: PMC7660596 DOI: 10.3390/ijms21217875] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 10/21/2020] [Accepted: 10/21/2020] [Indexed: 12/27/2022] Open
Abstract
Xylan is the most abundant hemicellulose, constitutes about 25–35% of the dry biomass of woody and lignified tissues, and occurs up to 50% in some cereal grains. The accurate degree and position of xylan acetylation is necessary for xylan function and for plant growth and development. The post synthetic acetylation of cell wall xylan, mainly regulated by Reduced Wall Acetylation (RWA), Trichome Birefringence-Like (TBL), and Altered Xyloglucan 9 (AXY9) genes, is essential for effective bonding of xylan with cellulose. Recent studies have proven that not only xylan acetylation but also its deacetylation is vital for various plant functions. Thus, the present review focuses on the latest advances in understanding xylan acetylation and deacetylation and explores their effects on plant growth and development. Baseline knowledge about precise regulation of xylan acetylation and deacetylation is pivotal to developing plant biomass better suited for second-generation liquid biofuel production.
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Affiliation(s)
- Mirza Faisal Qaseem
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou 510642, China;
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architectures, South China Agricultural University, Guangzhou 510642, China
| | - Ai-Min Wu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou 510642, China;
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architectures, South China Agricultural University, Guangzhou 510642, China
- Guangdong Laboratory of Lingnan Modern Agriculture, Guangzhou 510642, China
- Correspondence:
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