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Keret R, Drew DM, Hills PN. Xylem cell size regulation is a key adaptive response to water deficit in Eucalyptus grandis. TREE PHYSIOLOGY 2024; 44:tpae068. [PMID: 38896029 PMCID: PMC11247191 DOI: 10.1093/treephys/tpae068] [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: 02/14/2024] [Revised: 06/06/2024] [Accepted: 06/18/2024] [Indexed: 06/21/2024]
Abstract
Future climatic scenarios forecast increasingly frequent droughts that will pose substantial consequences on tree mortality. In light of this, drought-tolerant eucalypts have been propagated; however, the severity of these conditions will invoke adaptive responses, impacting the commercially valuable wood properties. To determine what mechanisms govern the wood anatomical adaptive response, highly controlled drought experiments were conducted in Eucalyptus grandis W. Hill ex Maiden, with the tree physiology and transcriptome closely monitored. In response to water deficit, E. grandis displays an isohydric stomatal response to conserve water and enable stem growth to continue, albeit at a reduced rate. Maintaining gaseous exchange is likely a critical short-term response that drives the formation of hydraulically safer xylem. For instance, the development of significantly smaller fibers and vessels was found to increase cellular density, thereby promoting drought tolerance through improved functional redundancy, as well as implosion and cavitation resistance. The transcriptome was explored to identify the molecular mechanisms responsible for controlling xylem cell size during prolonged water deficit. Downregulation of genes associated with cell wall remodeling and the biosynthesis of cellulose, hemicellulose and pectin appeared to coincide with a reduction in cellular enlargement during drought. Furthermore, transcript levels of NAC and MYB transcription factors, vital for cell wall component biosynthesis, were reduced, while those linked to lignification increased. The upregulation of EgCAD and various peroxidases under water deficit did not correlate with an increased lignin composition. However, with the elevated cellular density, a higher lignin content per xylem cross-sectional area was observed, potentially enhancing hydraulic safety. These results support the requirement for higher density, drought-adapted wood as a long-term adaptive response in E. grandis, which is largely influenced by the isohydric stomatal response coupled with cellular expansion-related molecular processes.
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Affiliation(s)
- Rafael Keret
- Institute for Plant Biotechnology, Department of Genetics, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch 7602, South Africa
- Department of Forestry and Wood Sciences, Stellenbosch University, Bosman St, Stellenbosch 7599, South Africa
| | - David M Drew
- Department of Forestry and Wood Sciences, Stellenbosch University, Bosman St, Stellenbosch 7599, South Africa
| | - Paul N Hills
- Institute for Plant Biotechnology, Department of Genetics, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch 7602, South Africa
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2
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Delmer D, Dixon RA, Keegstra K, Mohnen D. The plant cell wall-dynamic, strong, and adaptable-is a natural shapeshifter. THE PLANT CELL 2024; 36:1257-1311. [PMID: 38301734 PMCID: PMC11062476 DOI: 10.1093/plcell/koad325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 12/19/2023] [Indexed: 02/03/2024]
Abstract
Mythology is replete with good and evil shapeshifters, who, by definition, display great adaptability and assume many different forms-with several even turning themselves into trees. Cell walls certainly fit this definition as they can undergo subtle or dramatic changes in structure, assume many shapes, and perform many functions. In this review, we cover the evolution of knowledge of the structures, biosynthesis, and functions of the 5 major cell wall polymer types that range from deceptively simple to fiendishly complex. Along the way, we recognize some of the colorful historical figures who shaped cell wall research over the past 100 years. The shapeshifter analogy emerges more clearly as we examine the evolving proposals for how cell walls are constructed to allow growth while remaining strong, the complex signaling involved in maintaining cell wall integrity and defense against disease, and the ways cell walls adapt as they progress from birth, through growth to maturation, and in the end, often function long after cell death. We predict the next century of progress will include deciphering cell type-specific wall polymers; regulation at all levels of polymer production, crosslinks, and architecture; and how walls respond to developmental and environmental signals to drive plant success in diverse environments.
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Affiliation(s)
- Deborah Delmer
- Section of Plant Biology, University of California Davis, Davis, CA 95616, USA
| | - Richard A Dixon
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, TX 76203, USA
| | - Kenneth Keegstra
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48823, USA
| | - Debra Mohnen
- Complex Carbohydrate Research Center and Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
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3
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Javaid T, Bhattarai M, Venkataraghavan A, Held M, Faik A. Specific protein interactions between rice members of the GT43 and GT47 families form various central cores of putative xylan synthase complexes. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 118:856-878. [PMID: 38261531 DOI: 10.1111/tpj.16640] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 01/04/2024] [Accepted: 01/08/2024] [Indexed: 01/25/2024]
Abstract
Members of the glycosyltransferase (GT)43 and GT47 families have been associated with heteroxylan synthesis in both dicots and monocots and are thought to assemble into central cores of putative xylan synthase complexes (XSCs). Currently, it is unknown whether protein-protein interactions within these central cores are specific, how many such complexes exist, and whether these complexes are functionally redundant. Here, we used gene association network and co-expression approaches in rice to identify four OsGT43s and four OsGT47s that assemble into different GT43/GT47 complexes. Using two independent methods, we showed that (i) these GTs assemble into at least six unique complexes through specific protein-protein interactions and (ii) the proteins interact directly in vitro. Confocal microscopy showed that, when alone, all OsGT43s were retained in the endoplasmic reticulum (ER), while all OsGT47s were localized in the Golgi. co-expression of OsGT43s and OsGT47s displayed complexes that form in the ER but accumulate in Golgi. ER-to-Golgi trafficking appears to require interactions between OsGT43s and OsGT47s. Comparison of the central cores of the three putative rice OsXSCs to wheat, asparagus, and Arabidopsis XSCs, showed great variation in GT43/GT47 combinations, which makes the identification of orthologous central cores between grasses and dicots challenging. However, the emerging picture is that all central cores from these species seem to have at least one member of the IRX10/IRX10-L clade in the GT47 family in common, suggesting greater functional importance for this family in xylan synthesis. Our findings provide a new framework for future investigation of heteroxylan biosynthesis and function in monocots.
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Affiliation(s)
- Tasleem Javaid
- Department of Environmental and Plant Biology, Ohio University, Athens, Ohio, 45701, USA
| | - Matrika Bhattarai
- Department of Environmental and Plant Biology, Ohio University, Athens, Ohio, 45701, USA
| | | | - Michael Held
- Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio, 45701, USA
| | - Ahmed Faik
- Department of Environmental and Plant Biology, Ohio University, Athens, Ohio, 45701, USA
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Zhang L, Zhou Y, Zhang B. Xylan-directed cell wall assembly in grasses. PLANT PHYSIOLOGY 2024; 194:2197-2207. [PMID: 38095432 DOI: 10.1093/plphys/kiad665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 12/05/2023] [Indexed: 04/02/2024]
Abstract
Xylan is the most abundant hemicellulosic polysaccharide in the cell walls of grasses and is pivotal for the assembly of distinct cell wall structures that govern various cellular functions. Xylan also plays a crucial role in regulating biomass recalcitrance, ultimately affecting the utilization potential of lignocellulosic materials. Over the past decades, our understanding of the xylan biosynthetic machinery and cell wall organization has substantially improved due to the innovative application of multiple state-of-the-art techniques. Notably, novel xylan-based nanostructures have been revealed in the cell walls of xylem vessels, promoting a more extensive exploration of the role of xylan in the formation of cell wall structures. This Update summarizes recent achievements in understanding xylan biosynthesis, modification, modeling, and compartmentalization in grasses, providing a brief overview of cell wall assembly regarding xylan. We also discuss the potential for tailoring xylan to facilitate the breeding of elite energy and feed crops.
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Affiliation(s)
- Lanjun Zhang
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yihua Zhou
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- College of Advanced Agricultural Sciences, College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Baocai Zhang
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- College of Advanced Agricultural Sciences, College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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Cao L, Lin M, Ning J, Meng X, Pu X, Zhang R, Wu Q, Huang Z, Zhou J. Critical Roles of Acidic Residues in Loop Regions of the Structural Surface for the Salt Tolerance of a GH39 β-d-Xylosidase. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:5805-5815. [PMID: 38451212 DOI: 10.1021/acs.jafc.3c07957] [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: 03/08/2024]
Abstract
Xylan is the main component of hemicellulose. Complete hydrolysis of xylan requires synergistically acting xylanases, such as β-d-xylosidases. Salt-tolerant β-d-xylosidases have significant application benefits, but few reports have explored the critical amino acids affecting the salt tolerance of xylosidases. Herein, the site-directed mutation was used to demonstrate that negative electrostatic potentials generated by 19 acidic residues in the loop regions of the structural surface positively correlated with the improved salt tolerance of GH39 β-d-xylosidase JB13GH39P28. These mutants showed reduced negative potentials on structural surfaces as well as a 13-43% decrease in stability in 3.0-30.0% (w/v) NaCl. Six key residue sites, D201, D259, D297, D377, D395, and D474, were confirmed to influence both the stability and activity of GH39 β-d-xylosidase. The activity of the GH39 β-d-xylosidase was found promoting by SO42- and inhibiting by NO3-. Values of Km and Kcat/Km decreased aggravatedly in 30.0% (w/v) NaCl when mutation operated on residues E179 and D182 in the loop regions of the catalytic domain. Taken together, mutation on acidic residues in loop regions from catalytic and noncatalytic domains may cause the deformation of catalytic pocket and aggregation of protein particles then decrease the stability, binding affinity, and catalytic efficiency of the β-d-xylosidase.
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Affiliation(s)
- Lijuan Cao
- College of Life Sciences, Yunnan Normal University, Kunming 650500, People's Republic of China
| | - Mingyue Lin
- College of Life Sciences, Yunnan Normal University, Kunming 650500, People's Republic of China
| | - Juan Ning
- College of Life Sciences, Yunnan Normal University, Kunming 650500, People's Republic of China
| | - Xin Meng
- College of Life Sciences, Yunnan Normal University, Kunming 650500, People's Republic of China
| | - Xiong Pu
- College of Life Sciences, Yunnan Normal University, Kunming 650500, People's Republic of China
| | - Rui Zhang
- College of Life Sciences, Yunnan Normal University, Kunming 650500, People's Republic of China
- Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, People's Republic of China
- Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Kunming, Yunnan 650500, People's Republic of China
- Key Laboratory of Yunnan Provincial Education Department for Plateau Characteristic Food Enzymes, Yunnan Normal University, Kunming 650500, People's Republic of China
| | - Qian Wu
- College of Life Sciences, Yunnan Normal University, Kunming 650500, People's Republic of China
- Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, People's Republic of China
- Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Kunming, Yunnan 650500, People's Republic of China
- Key Laboratory of Yunnan Provincial Education Department for Plateau Characteristic Food Enzymes, Yunnan Normal University, Kunming 650500, People's Republic of China
| | - Zunxi Huang
- College of Life Sciences, Yunnan Normal University, Kunming 650500, People's Republic of China
- Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, People's Republic of China
- Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Kunming, Yunnan 650500, People's Republic of China
- Key Laboratory of Yunnan Provincial Education Department for Plateau Characteristic Food Enzymes, Yunnan Normal University, Kunming 650500, People's Republic of China
| | - Junpei Zhou
- College of Life Sciences, Yunnan Normal University, Kunming 650500, People's Republic of China
- Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, People's Republic of China
- Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Kunming, Yunnan 650500, People's Republic of China
- Key Laboratory of Yunnan Provincial Education Department for Plateau Characteristic Food Enzymes, Yunnan Normal University, Kunming 650500, People's Republic of China
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Prins A, Kosik O. Genetic Approaches to Increase Arabinoxylan and β-Glucan Content in Wheat. PLANTS (BASEL, SWITZERLAND) 2023; 12:3216. [PMID: 37765380 PMCID: PMC10534680 DOI: 10.3390/plants12183216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 08/24/2023] [Accepted: 08/28/2023] [Indexed: 09/29/2023]
Abstract
Wheat is one of the three staple crops feeding the world. The demand for wheat is ever increasing as a relatively good source of protein, energy, nutrients, and dietary fiber (DF) when consumed as wholemeal. Arabinoxylan and β-glucan are the major hemicelluloses in the cell walls and dietary fiber in wheat grains. The amount and structure of DF varies between grain tissues. Reducing post-prandial glycemic response as well as intestinal transit time and contribution to increased fecal bulk are only a few benefits of DF consumption. Dietary fiber is fermented in the colon and stimulates growth of beneficial bacteria producing SCFA, considered responsible for a wide range of health benefits, including reducing the risk of heart disease and colon cancer. The recommended daily intake of 25-30 g is met by only few individuals. Cereals cover nearly 40% of fiber in the Western diet. Therefore, wheat is a good target for improving dietary fiber content, as it would increase the fiber intake and simultaneously impact the health of many people. This review reflects the current status of the research on genetics of the two major dietary fiber components, as well as breeding approaches used to improve their quantity and quality in wheat grain.
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Affiliation(s)
- Anneke Prins
- Department of Sustainable Soils and Crops, Rothamsted Research, Harpenden AL5 2JQ, UK;
| | - Ondrej Kosik
- Department of Plant Sciences for the Bioeconomy, Rothamsted Research, Harpenden AL5 2JQ, UK
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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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