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Boerjan W, Strauss SH. Social and biological innovations are essential to deliver transformative forest biotechnologies. THE NEW PHYTOLOGIST 2024; 243:526-536. [PMID: 38803120 DOI: 10.1111/nph.19855] [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: 02/01/2024] [Accepted: 04/30/2024] [Indexed: 05/29/2024]
Abstract
Forests make immense contributions to societies in the form of ecological services and sustainable industrial products. However, they face major challenges to their viability and economic use due to climate change and growing biotic and economic threats, for which recombinant DNA (rDNA) technology can sometimes provide solutions. But the application of rDNA technologies to forest trees faces major social and biological obstacles that make its societal acceptance a 'wicked' problem without straightforward solutions. We discuss the nature of these problems, and the social and biological innovations that we consider essential for progress. As case studies of biological challenges, we focus on studies of modifications in wood chemistry and transformation efficiency. We call for major innovations in regulations, and the dissolution of method-based market barriers, that together could lead to greater research investments, enable wide use of field studies, and facilitate the integration of rDNA-modified trees into conventional breeding programs. Without near-term adoption of such innovations, rDNA-based solutions will be largely unavailable to help forests adapt to the growing stresses from climate change and the proliferation of forest pests, nor will they be available to provide economic and environmental benefits from expanded use of wood and related bioproducts as part of an expanding bioeconomy.
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Affiliation(s)
- Wout Boerjan
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, 9052, Ghent, Belgium
- Center for Plant Systems Biology, VIB, Technologiepark 71, 9052, Ghent, Belgium
| | - Steven H Strauss
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR, 97331, USA
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2
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Dixon RA, Puente-Urbina A, Beckham GT, Román-Leshkov Y. Enabling Lignin Valorization Through Integrated Advances in Plant Biology and Biorefining. ANNUAL REVIEW OF PLANT BIOLOGY 2024; 75:239-263. [PMID: 39038247 DOI: 10.1146/annurev-arplant-062923-022602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/24/2024]
Abstract
Despite lignin having long been viewed as an impediment to the processing of biomass for the production of paper, biofuels, and high-value chemicals, the valorization of lignin to fuels, chemicals, and materials is now clearly recognized as a critical element for the lignocellulosic bioeconomy. However, the intended application for lignin will likely require a preferred lignin composition and form. To that end, effective lignin valorization will require the integration of plant biology, providing optimal feedstocks, with chemical process engineering, providing efficient lignin transformations. Recent advances in our understanding of lignin biosynthesis have shown that lignin structure is extremely diverse and potentially tunable, while simultaneous developments in lignin refining have resulted in the development of several processes that are more agnostic to lignin composition. Here, we review the interface between in planta lignin design and lignin processing and discuss the advances necessary for lignin valorization to become a feature of advanced biorefining.
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Affiliation(s)
- Richard A Dixon
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, Texas, USA;
- Center for Bioenergy Innovation (CBI), Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Allen Puente-Urbina
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Gregg T Beckham
- Center for Bioenergy Innovation (CBI), Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Yuriy Román-Leshkov
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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3
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Blaschek L, Serk H, Pesquet E. Functional Complexity on a Cellular Scale: Why In Situ Analyses Are Indispensable for Our Understanding of Lignified Tissues. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024. [PMID: 38832924 DOI: 10.1021/acs.jafc.4c01999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2024]
Abstract
Lignins are a key adaptation that enables vascular plants to thrive in terrestrial habitats. Lignin is heterogeneous, containing upward of 30 different monomers, and its function is multifarious: It provides structural support, predetermined breaking points, ultraviolet protection, diffusion barriers, pathogen resistance, and drought resilience. Recent studies, carefully characterizing lignin in situ, have started to identify specific lignin compositions and ultrastructures with distinct cellular functions, but our understanding remains fractional. We summarize recent works and highlight where further in situ lignin analysis could provide valuable insights into plant growth and adaptation. We also summarize strengths and weaknesses of lignin in situ analysis methods.
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Affiliation(s)
- Leonard Blaschek
- Copenhagen Plant Science Center (CPSC), Department of Plant & Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Henrik Serk
- Umeå Plant Science Centre (UPSC), Department of Plant Physiology, Umeå University, 901 87 Umeå, Sweden
| | - Edouard Pesquet
- Department of Ecology, Environment and Plant Sciences (DEEP), Stockholm University, 106 91 Stockholm, Sweden
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4
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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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5
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Dwivedi N, Yamamoto S, Zhao Y, Hou G, Bowling F, Tobimatsu Y, Liu C. Simultaneous suppression of lignin, tricin and wall-bound phenolic biosynthesis via the expression of monolignol 4-O-methyltransferases in rice. PLANT BIOTECHNOLOGY JOURNAL 2024; 22:330-346. [PMID: 37795899 PMCID: PMC10826995 DOI: 10.1111/pbi.14186] [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: 02/27/2023] [Revised: 07/14/2023] [Accepted: 09/16/2023] [Indexed: 10/06/2023]
Abstract
Grass lignocelluloses feature complex compositions and structures. In addition to the presence of conventional lignin units from monolignols, acylated monolignols and flavonoid tricin also incorporate into lignin polymer; moreover, hydroxycinnamates, particularly ferulate, cross-link arabinoxylan chains with each other and/or with lignin polymers. These structural complexities make grass lignocellulosics difficult to optimize for effective agro-industrial applications. In the present study, we assess the applications of two engineered monolignol 4-O-methyltransferases (MOMTs) in modifying rice lignocellulosic properties. Two MOMTs confer regiospecific para-methylation of monolignols but with different catalytic preferences. The expression of MOMTs in rice resulted in differential but drastic suppression of lignin deposition, showing more than 50% decrease in guaiacyl lignin and up to an 90% reduction in syringyl lignin in transgenic lines. Moreover, the levels of arabinoxylan-bound ferulate were reduced by up to 50%, and the levels of tricin in lignin fraction were also substantially reduced. Concomitantly, up to 11 μmol/g of the methanol-extractable 4-O-methylated ferulic acid and 5-7 μmol/g 4-O-methylated sinapic acid were accumulated in MOMT transgenic lines. Both MOMTs in vitro displayed discernible substrate promiscuity towards a range of phenolics in addition to the dominant substrate monolignols, which partially explains their broad effects on grass phenolic biosynthesis. The cell wall structural and compositional changes resulted in up to 30% increase in saccharification yield of the de-starched rice straw biomass after diluted acid-pretreatment. These results demonstrate an effective strategy to tailor complex grass cell walls to generate improved cellulosic feedstocks for the fermentable sugar-based production of biofuel and bio-chemicals.
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Affiliation(s)
- Nidhi Dwivedi
- Biology DepartmentBrookhaven Nation LaboratoryUptonNew YorkUSA
- Feedstocks DivisionJoint BioEnergy InstituteEmeryvilleCAUSA
| | - Senri Yamamoto
- Research Institute for Sustainable HumanosphereKyoto UniversityGokasho, UjiKyotoJapan
| | - Yunjun Zhao
- Biology DepartmentBrookhaven Nation LaboratoryUptonNew YorkUSA
| | - Guichuan Hou
- Dewel Microscopy FacilityAppalachian State UniversityBooneNorth CarolinaUSA
| | - Forrest Bowling
- Biology DepartmentBrookhaven Nation LaboratoryUptonNew YorkUSA
| | - Yuki Tobimatsu
- Research Institute for Sustainable HumanosphereKyoto UniversityGokasho, UjiKyotoJapan
| | - Chang‐Jun Liu
- Biology DepartmentBrookhaven Nation LaboratoryUptonNew YorkUSA
- Feedstocks DivisionJoint BioEnergy InstituteEmeryvilleCAUSA
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6
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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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7
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Wouters M, Bastiaanse H, Rombauts S, de Vries L, De Pooter T, Strazisar M, Neutelings G, Vanholme R, Boerjan W. Suppression of the Arabidopsis cinnamoyl-CoA reductase 1-6 intronic T-DNA mutation by epigenetic modification. PLANT PHYSIOLOGY 2023; 192:3001-3016. [PMID: 37139862 PMCID: PMC7614886 DOI: 10.1093/plphys/kiad261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 04/10/2023] [Accepted: 04/10/2023] [Indexed: 05/05/2023]
Abstract
Arabidopsis (Arabidopsis thaliana) transfer DNA (T-DNA) insertion collections are popular resources for fundamental plant research. Cinnamoyl-CoA reductase 1 (CCR1) catalyzes an essential step in the biosynthesis of the cell wall polymer lignin. Accordingly, the intronic T-DNA insertion mutant ccr1-6 has reduced lignin levels and shows a stunted growth phenotype. Here, we report restoration of the ccr1-6 mutant phenotype and CCR1 expression levels after a genetic cross with a UDP-glucosyltransferase 72e1 (ugt72e1),-e2,-e3 T-DNA mutant. We discovered that the phenotypic recovery was not dependent on the UGT72E family loss of function but due to an epigenetic phenomenon called trans T-DNA suppression. Via trans T-DNA suppression, the gene function of an intronic T-DNA mutant was restored after the introduction of an additional T-DNA sharing identical sequences, leading to heterochromatinization and splicing out of the T-DNA-containing intron. Consequently, the suppressed ccr1-6 allele was named epiccr1-6. Long-read sequencing revealed that epiccr1-6, not ccr1-6, carries dense cytosine methylation over the full length of the T-DNA. We showed that the SAIL T-DNA in the UGT72E3 locus could trigger the trans T-DNA suppression of the GABI-Kat T-DNA in the CCR1 locus. Furthermore, we scanned the literature for other potential cases of trans T-DNA suppression in Arabidopsis and found that 22% of the publications matching our query report on double or higher-order T-DNA mutants that meet the minimal requirements for trans T-DNA suppression. These combined observations indicate that intronic T-DNA mutants need to be used with caution since methylation of intronic T-DNA might derepress gene expression and can thereby confound results.
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Affiliation(s)
- Marlies Wouters
- VIB Center for Plants Systems Biology, VIB, Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
| | - Héloïse Bastiaanse
- VIB Center for Plants Systems Biology, VIB, Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
| | - Stéphane Rombauts
- VIB Center for Plants Systems Biology, VIB, Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
| | - Lisanne de Vries
- VIB Center for Plants Systems Biology, VIB, Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
| | - Tim De Pooter
- Neuromics Support Facility, VIB Center for Molecular Neurology, VIB, Antwerp, Belgium
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Mojca Strazisar
- Neuromics Support Facility, VIB Center for Molecular Neurology, VIB, Antwerp, Belgium
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Godfrey Neutelings
- Unité de Glycobiologie Structurale et Fonctionnelle (UGSF), UMR 8576, CNRS, Université de Lille, Lille, France
| | - Ruben Vanholme
- VIB Center for Plants Systems Biology, VIB, Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
| | - Wout Boerjan
- VIB Center for Plants Systems Biology, VIB, Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
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De Meester B, Vanholme R, Mota T, Boerjan W. Lignin engineering in forest trees: From gene discovery to field trials. PLANT COMMUNICATIONS 2022; 3:100465. [PMID: 36307984 PMCID: PMC9700206 DOI: 10.1016/j.xplc.2022.100465] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 10/10/2022] [Accepted: 10/21/2022] [Indexed: 06/16/2023]
Abstract
Wood is an abundant and renewable feedstock for the production of pulp, fuels, and biobased materials. However, wood is recalcitrant toward deconstruction into cellulose and simple sugars, mainly because of the presence of lignin, an aromatic polymer that shields cell-wall polysaccharides. Hence, numerous research efforts have focused on engineering lignin amount and composition to improve wood processability. Here, we focus on results that have been obtained by engineering the lignin biosynthesis and branching pathways in forest trees to reduce cell-wall recalcitrance, including the introduction of exotic lignin monomers. In addition, we draw general conclusions from over 20 years of field trial research with trees engineered to produce less or altered lignin. We discuss possible causes and solutions for the yield penalty that is often associated with lignin engineering in trees. Finally, we discuss how conventional and new breeding strategies can be combined to develop elite clones with desired lignin properties. We conclude this review with priorities for the development of commercially relevant lignin-engineered trees.
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Affiliation(s)
- Barbara De Meester
- Ghent University, Department of Plant Biotechnology and Bioinformatics, Technologiepark 71, 9052 Ghent, Belgium; VIB Center for Plant Systems Biology, Technologiepark 71, 9052 Ghent, Belgium
| | - Ruben Vanholme
- Ghent University, Department of Plant Biotechnology and Bioinformatics, Technologiepark 71, 9052 Ghent, Belgium; VIB Center for Plant Systems Biology, Technologiepark 71, 9052 Ghent, Belgium
| | - Thatiane Mota
- Ghent University, Department of Plant Biotechnology and Bioinformatics, Technologiepark 71, 9052 Ghent, Belgium; VIB Center for Plant Systems Biology, Technologiepark 71, 9052 Ghent, Belgium
| | - Wout Boerjan
- Ghent University, Department of Plant Biotechnology and Bioinformatics, Technologiepark 71, 9052 Ghent, Belgium; VIB Center for Plant Systems Biology, Technologiepark 71, 9052 Ghent, Belgium.
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Wouters M, Corneillie S, Dewitte A, Van Doorsselaere J, Van den Bulcke J, Van Acker J, Vanholme B, Boerjan W. Whole genome duplication of wild-type and CINNAMYL ALCOHOL DEHYDROGENASE1-downregulated hybrid poplar reduces biomass yield and causes a brittle apex phenotype in field-grown wild types. FRONTIERS IN PLANT SCIENCE 2022; 13:995402. [PMID: 36160989 PMCID: PMC9504066 DOI: 10.3389/fpls.2022.995402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 08/22/2022] [Indexed: 06/16/2023]
Abstract
The potential of whole genome duplication to increase plant biomass yield is well-known. In Arabidopsis tetraploids, an increase in biomass yield was accompanied by a reduction in lignin content and, as a result, a higher saccharification efficiency was achieved compared with diploid controls. Here, we evaluated whether the results obtained in Arabidopsis could be translated into poplar and whether the enhanced saccharification yield upon alkaline pretreatment of hairpin-downregulated CINNAMYL ALCOHOL DEHYDROGENASE1 (hpCAD) transgenic poplar could be further improved upon a whole genome duplication. Using a colchicine treatment, wild-type (WT) Populus tremula x P. alba cv. INRA 717-1B4, a commonly used model clone in tree biotechnology research, and hpCAD tetraploids were generated and grown in the greenhouse. In parallel, WT tetraploid poplars were grown in the field. In contrast to Arabidopsis, a whole genome duplication of poplar had a negative impact on the biomass yield of both greenhouse- and field-grown trees. Strikingly, field-grown WT tetraploids developed a brittle apex phenotype, i.e., their tip broke off just below the apex. In addition, the chromosome doubling altered the biomass composition of field-grown, but not of greenhouse-grown tetraploid poplars. More specifically, the lignin content of field-grown tetraploid poplars was increased at the expense of matrix polysaccharides. This increase in lignin deposition in biomass is likely the cause of the observed brittle apex phenotype, though no major differences in stem anatomy or in mechanical properties could be found between di- and tetraploid WT poplars grown in the field. Finally, without biomass pretreatment, the saccharification efficiency of greenhouse- and field-grown WT diploids was not different from that of tetraploids, whereas that of greenhouse-grown hpCAD tetraploids was higher than that of greenhouse-grown diploids. Upon alkaline pretreatment, the saccharification yield of diploids was similar to that of tetraploids for all genotypes and growth conditions tested. This study showed that a whole genome duplication in hybrid WT and hpCAD poplar did neither result in further improvements in biomass yield, nor in improved biomass composition and, hence, saccharification performance.
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Affiliation(s)
- Marlies Wouters
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Sander Corneillie
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Angelo Dewitte
- Expertisecentrum Agro- en Biotechnologie, VIVES, Roeselare, Belgium
| | | | - Jan Van den Bulcke
- Laboratory of Wood Technology, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Joris Van Acker
- Laboratory of Wood Technology, Department of Environment, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Bartel Vanholme
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Wout Boerjan
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
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10
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De Meester B, Oyarce P, Vanholme R, Van Acker R, Tsuji Y, Vangeel T, Van den Bosch S, Van Doorsselaere J, Sels B, Ralph J, Boerjan W. Engineering Curcumin Biosynthesis in Poplar Affects Lignification and Biomass Yield. FRONTIERS IN PLANT SCIENCE 2022; 13:943349. [PMID: 35860528 PMCID: PMC9289561 DOI: 10.3389/fpls.2022.943349] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 06/14/2022] [Indexed: 06/02/2023]
Abstract
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 DIKETIDE-CoA SYNTHASE (DCS) and CURCUMIN SYNTHASE2 (CURS2). The resulting transgenic plants did not suffer from yield penalties and had an increased saccharification yield after alkaline pretreatment. Here, we translated this strategy into the bio-energy crop poplar. Via the heterologous expression of DCS and CURS2 under the control of the secondary cell wall CELLULOSE SYNTHASE A8-B promoter (ProCesA8-B), curcumin was also produced and incorporated into the lignified cell walls of poplar. ProCesA8-B:DCS_CURS2 transgenic poplars, however, suffered from shoot-tip necrosis and yield penalties. Compared to that of the wild-type (WT), the wood of transgenic poplars had 21% less cellulose, 28% more matrix polysaccharides, 23% more lignin and a significantly altered lignin composition. More specifically, ProCesA8-B:DCS_CURS2 lignin had a reduced syringyl/guaiacyl unit (S/G) ratio, an increased frequency of p-hydroxyphenyl (H) units, a decreased frequency of p-hydroxybenzoates and a higher fraction of phenylcoumaran units. Without, or with alkaline or hot water pretreatment, the saccharification efficiency of the transgenic lines was equal to that of the WT. These differences in (growth) phenotype illustrate that translational research in crops is essential to assess the value of an engineering strategy for applications. Further fine-tuning of this research strategy (e.g., by using more specific promoters or by translating this strategy to other crops such as maize) might lead to transgenic bio-energy crops with cell walls more amenable to deconstruction without settling in yield.
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Affiliation(s)
- Barbara De Meester
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Paula Oyarce
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Ruben Vanholme
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Rebecca Van Acker
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Yukiko Tsuji
- Department of Biochemistry, University of Wisconsin, Madison, WI, United States
- US Department of Energy, Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, Madison, WI, United States
| | - Thijs Vangeel
- Center for Sustainable Catalysis and Engineering, KU Leuven, Leuven, Belgium
| | | | | | - Bert Sels
- Center for Sustainable Catalysis and Engineering, KU Leuven, Leuven, Belgium
| | - John Ralph
- Department of Biochemistry, University of Wisconsin, Madison, WI, United States
- US Department of Energy, Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, Madison, WI, United States
| | - Wout Boerjan
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
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Wang Y, Gui C, Wu J, Gao X, Huang T, Cui F, Liu H, Sethupathy S. Spatio-Temporal Modification of Lignin Biosynthesis in Plants: A Promising Strategy for Lignocellulose Improvement and Lignin Valorization. Front Bioeng Biotechnol 2022; 10:917459. [PMID: 35845403 PMCID: PMC9283729 DOI: 10.3389/fbioe.2022.917459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 06/14/2022] [Indexed: 11/13/2022] Open
Abstract
Lignin is essential for plant growth, structural integrity, biotic/abiotic stress resistance, and water transport. Besides, lignin constitutes 10–30% of lignocellulosic biomass and is difficult to utilize for biofuel production. Over the past few decades, extensive research has uncovered numerous metabolic pathways and genes involved in lignin biosynthesis, several of which have been highlighted as the primary targets for genetic manipulation. However, direct manipulation of lignin biosynthesis is often associated with unexpected abnormalities in plant growth and development for unknown causes, thus limiting the usefulness of genetic engineering for biomass production and utilization. Recent advances in understanding the complex regulatory mechanisms of lignin biosynthesis have revealed new avenues for spatial and temporal modification of lignin in lignocellulosic plants that avoid growth abnormalities. This review explores recent work on utilizing specific transcriptional regulators to modify lignin biosynthesis at both tissue and cellular levels, focusing on using specific promoters paired with functional or regulatory genes to precisely control lignin synthesis and achieve biomass production with desired properties. Further advances in designing more appropriate promoters and other regulators will increase our capacity to modulate lignin content and structure in plants, thus setting the stage for high-value utilization of lignin in the future.
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Affiliation(s)
- Yongli Wang
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, China
- *Correspondence: Yongli Wang, ; Sivasamy Sethupathy,
| | - Cunjin Gui
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, China
| | - Jiangyan Wu
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, China
| | - Xing Gao
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, China
| | - Ting Huang
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, China
| | - Fengjie Cui
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, China
| | - Huan Liu
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, China
| | - Sivasamy Sethupathy
- Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, China
- *Correspondence: Yongli Wang, ; Sivasamy Sethupathy,
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Overexpression of EgrIAA20 from Eucalyptus grandis, a Non-Canonical Aux/ IAA Gene, Specifically Decouples Lignification of the Different Cell-Types in Arabidopsis Secondary Xylem. Int J Mol Sci 2022; 23:ijms23095068. [PMID: 35563457 PMCID: PMC9100763 DOI: 10.3390/ijms23095068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 04/22/2022] [Accepted: 04/26/2022] [Indexed: 11/26/2022] Open
Abstract
Wood (secondary xylem) formation is regulated by auxin, which plays a pivotal role as an integrator of developmental and environmental cues. However, our current knowledge of auxin-signaling during wood formation is incomplete. Our previous genome-wide analysis of Aux/IAAs in Eucalyptus grandis showed the presence of the non-canonical paralog member EgrIAA20 that is preferentially expressed in cambium. We analyzed its cellular localization using a GFP fusion protein and its transcriptional activity using transactivation assays, and demonstrated its nuclear localization and strong auxin response repressor activity. In addition, we functionally tested the role of EgrIAA20 by constitutive overexpression in Arabidopsis to investigate for phenotypic changes in secondary xylem formation. Transgenic Arabidopsis plants overexpressing EgrIAA20 were smaller and displayed impaired development of secondary fibers, but not of other wood cell types. The inhibition in fiber development specifically affected their cell wall lignification. We performed yeast-two-hybrid assays to identify EgrIAA20 protein partners during wood formation in Eucalyptus, and identified EgrIAA9A, whose ortholog PtoIAA9 in poplar is also known to be involved in wood formation. Altogether, we showed that EgrIAA20 is an important auxin signaling component specifically involved in controlling the lignification of wood fibers.
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