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Xiang Y, Kagawa A, Nagai S, Yasuda Y, Utsumi Y. Isotope Distribution Analysis in H₂ 18O Pulse-Labeled Trees Frozen with Liquid Nitrogen. PHYSIOLOGIA PLANTARUM 2024; 176:e14292. [PMID: 38685817 DOI: 10.1111/ppl.14292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 03/24/2024] [Accepted: 04/01/2024] [Indexed: 05/02/2024]
Abstract
Tracer injection has long been recognized as a valuable tool for delineating tree hydraulics and assessing water transport pathways. Recently, isotope tracers have emerged as innovative instruments for investigating tree hydraulics, providing new insights into tree water dynamics. Nevertheless, there is a critical need for further research to comprehensively grasp water movement and distribution within trees. A previously introduced technique for analyzing the isotopic ratio of water in wet tissues, offering millimeter-scale resolution for visualizing tracer movement, faces challenges due to its underdeveloped sample preparation techniques. In this study, we introduced an H2 18O tracer into S. gracilistyla samples, exclusively comprising indeterminate roots, stems, and leaves, cultivated through hydroponics and grown within the current year. Our objective was to assess the axial distribution of the tracer in the xylem. Additionally, we devised a novel method for preparing frozen wet tissue samples, enhancing the repeatability and success rate of experiments. The results demonstrated that all frozen wet tissue samples exhibited an average water loss rate of less than 0.6%. Isotopic analysis of these samples unveiled a consistent decline in tracer concentration with increasing height in all Salix specimens, with three out of five samples revealing a significant isotope gradient. Our findings affirm the efficacy and practicality of combining isotopic labeling with freezing, stabilization, and preparation techniques. Looking ahead, our isotopic labeling and analysis methods are poised to transcend woody plants, finding extensive applications in plant physiology and ecohydrology.
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Affiliation(s)
- Yan Xiang
- Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, Japan
| | - Akira Kagawa
- Forestry and Forest Products Research Institute, Wood Anatomy and Quality Laboratory, Ibaraki, Japan
| | - Satoshi Nagai
- Forestry Technology Institute, Hyogo Prefectural Technology Center for Agriculture, Forestry and Fisheries, Hyogo, Japan
| | - Yuko Yasuda
- Department of Environmental Sciences and Technology, Faculty of Agriculture, Kagoshima University, Kagoshima City Kagoshima, Japan
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Kong L, Song Q, Wei H, Wang Y, Lin M, Sun K, Zhang Y, Yang J, Li C, Luo K. The AP2/ERF transcription factor PtoERF15 confers drought tolerance via JA-mediated signaling in Populus. THE NEW PHYTOLOGIST 2023; 240:1848-1867. [PMID: 37691138 DOI: 10.1111/nph.19251] [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: 07/19/2023] [Accepted: 08/15/2023] [Indexed: 09/12/2023]
Abstract
Drought stress is one of the major limiting factors for the growth and development of perennial trees. Xylem vessels act as the center of water conduction in woody species, but the underlying mechanism of its development and morphogenesis under water-deficient conditions remains elucidation. Here, we identified and characterized an osmotic stress-induced ETHYLENE RESPONSE FACTOR 15 (PtoERF15) and its target, PtoMYC2b, which was involved in mediating vessel size, density, and cell wall thickness in response to drought in Populus tomentosa. PtoERF15 is preferentially expressed in differentiating xylem of poplar stems. Overexpression of PtoERF15 contributed to stem water potential maintaining, thus promoting drought tolerance. RNA-Seq and biochemical analysis further revealed that PtoERF15 directly regulated PtoMYC2b, encoding a switch of JA signaling pathway. Additionally, our findings verify that three sets of homologous genes from NAC (NAM, ATAF1/2, and CUC2) gene family: PtoSND1-A1/A2, PtoVND7-1/7-2, and PtoNAC118/120, as the targets of PtoMYC2b, are involved in the regulation of vessel morphology in poplar. Collectively, our study provides molecular evidence for the involvement of the PtoERF15-PtoMYC2b transcription cascade in maintaining stem water potential through the regulation of xylem vessel development, ultimately improving drought tolerance in poplar.
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Affiliation(s)
- Lingfei Kong
- Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Integrative Science Center of Germplasm Creationin Western China (Chongqing) Science City, School of Life Sciences, Southwest University, Chongqing, 400715, China
- Key Laboratory of Eco-environments of Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Qin Song
- Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Integrative Science Center of Germplasm Creationin Western China (Chongqing) Science City, School of Life Sciences, Southwest University, Chongqing, 400715, China
- Key Laboratory of Eco-environments of Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Hongbin Wei
- Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Integrative Science Center of Germplasm Creationin Western China (Chongqing) Science City, School of Life Sciences, Southwest University, Chongqing, 400715, China
- Key Laboratory of Eco-environments of Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Yanhong Wang
- Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Integrative Science Center of Germplasm Creationin Western China (Chongqing) Science City, School of Life Sciences, Southwest University, Chongqing, 400715, China
- Key Laboratory of Eco-environments of Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Minghui Lin
- Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Integrative Science Center of Germplasm Creationin Western China (Chongqing) Science City, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Kuan Sun
- Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Integrative Science Center of Germplasm Creationin Western China (Chongqing) Science City, School of Life Sciences, Southwest University, Chongqing, 400715, China
- Key Laboratory of Eco-environments of Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Yuqian Zhang
- Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Integrative Science Center of Germplasm Creationin Western China (Chongqing) Science City, School of Life Sciences, Southwest University, Chongqing, 400715, China
- Key Laboratory of Eco-environments of Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Jiarui Yang
- Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Integrative Science Center of Germplasm Creationin Western China (Chongqing) Science City, School of Life Sciences, Southwest University, Chongqing, 400715, China
- Key Laboratory of Eco-environments of Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Chaofeng Li
- Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Integrative Science Center of Germplasm Creationin Western China (Chongqing) Science City, School of Life Sciences, Southwest University, Chongqing, 400715, China
- Maize Research Institute, Southwest University, Chongqing, 400715, China
- Engineering Research Center of South Upland Agriculture, Ministry of Education, Chongqing, 400715, China
| | - Keming Luo
- Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Integrative Science Center of Germplasm Creationin Western China (Chongqing) Science City, School of Life Sciences, Southwest University, Chongqing, 400715, China
- Key Laboratory of Eco-environments of Three Gorges Reservoir Region, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, 400715, China
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Xiang Y, Kagawa A, Nagai S, Yasuda Y, Utsumi Y. The difference in the functional water flow network between the stem and current-year root cross-sectional surfaces in Salix gracilistyla stem xylem. TREE PHYSIOLOGY 2023; 43:1326-1340. [PMID: 37098160 DOI: 10.1093/treephys/tpad056] [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: 11/10/2022] [Revised: 04/17/2023] [Accepted: 04/21/2023] [Indexed: 06/19/2023]
Abstract
The dye injection method has been applied to many species to analyze the xylem water transport pathway in trees. However, traditional dye injection methods introduced dye tracers from the surface of cut stems, including several annual rings. Furthermore, the traditional dye injection method did not evaluate radial water movement from the outermost annual rings to the inner annual rings. In this study, we assessed the difference in radial water movement visualized by an injected dye, between stem base cut and current-year root cut samples of Salix gracilistyla Miq., with current-year roots grown hydroponically. The results showed that the number of stained annual rings in the root cut samples was smaller than that in the stem cut samples, and the percentage of stained vessels in the root cut samples was significantly smaller than that in the stem base cut samples in the second and third annual rings. In the current-year root cut samples, water transport mainly occurred in the outermost rings from the current-year roots to leaves. In addition, the theoretical hydraulic conductivity of stained vessels in the stem cut samples was higher in the current-year root cut samples in the second and third annual rings. These findings indicate that the previously reported dye injection method using stem cut samples overestimated the water transport pathway in the inner part of the stems. Moreover, previous hydraulic conductivity measurement methods might not have considered the effects of radial resistance through the annual ring boundary, and they might have overestimated the hydraulic conductivity in the inner annual rings.
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Affiliation(s)
- Yan Xiang
- Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 744 Motooka, Nishi Ward, Fukuoka city, Fukuoka, 819-0385, Japan
| | - Akira Kagawa
- Forestry and Forest Products Research Institute, Wood Anatomy and Quality Laboratory, 1 Matsunosato, Tsukuba, Ibaraki 300-1244, Japan
| | - Satoshi Nagai
- Hyogo Prefectural Technology Center for Agriculture, Forestry and Fisheries, Forestry and Forest Products Research Institute, 430 Yamasakicho Ikaba, Shiso, Hyogo 671-2515, Japan
| | - Yuko Yasuda
- Department of Environmental Sciences and Technology, Faculty of Agriculture, Kagoshima University, 1 Chome-21-24 Korimoto, Kagoshima City Kagoshima, 890-0065, Japan
| | - Yasuhiro Utsumi
- Kyushu University Forest, Kyushu University, 394-1 Tsubakuro, Sasaguri, Kasuya District, Fukuoka 811-2415, Japan
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Thonglim A, Bortolami G, Delzon S, Larter M, Offringa R, Keurentjes JJB, Smets E, Balazadeh S, Lens F. Drought response in Arabidopsis displays synergistic coordination between stems and leaves. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:1004-1021. [PMID: 36350081 PMCID: PMC9899417 DOI: 10.1093/jxb/erac446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 11/07/2022] [Indexed: 06/16/2023]
Abstract
The synergy between drought-responsive traits across different organs is crucial in the whole-plant mechanism influencing drought resilience. These organ interactions, however, are poorly understood, limiting our understanding of drought response strategies at the whole-plant level. Therefore, we need more integrative studies, especially on herbaceous species that represent many important food crops but remain underexplored in their drought response. We investigated inflorescence stems and rosette leaves of six Arabidopsis thaliana genotypes with contrasting drought tolerance, and combined anatomical observations with hydraulic measurements and gene expression studies to assess differences in drought response. The soc1ful double mutant was the most drought-tolerant genotype based on its synergistic combination of low stomatal conductance, largest stomatal safety margin, more stable leaf water potential during non-watering, reduced transcript levels of drought stress marker genes, and reduced loss of chlorophyll content in leaves, in combination with stems showing the highest embolism resistance, most pronounced lignification, and thickest intervessel pit membranes. In contrast, the most sensitive Cvi ecotype shows the opposite extreme of the same set of traits. The remaining four genotypes show variations in this drought syndrome. Our results reveal that anatomical, ecophysiological, and molecular adaptations across organs are intertwined, and multiple (differentially combined) strategies can be applied to acquire a certain level of drought tolerance.
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Affiliation(s)
| | - Giovanni Bortolami
- Naturalis Biodiversity Center, Research Group Functional Traits, PO Box 9517, 2300 RA Leiden, The Netherlands
| | | | | | - Remko Offringa
- Leiden University, Institute of Biology Leiden, Plant Developmental Genetics, Sylviusweg 72, 2333 BE Leiden, The Netherlands
| | - Joost J B Keurentjes
- Laboratory of Genetics, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Erik Smets
- Naturalis Biodiversity Center, Research Group Functional Traits, PO Box 9517, 2300 RA Leiden, The Netherlands
- Leiden University, Institute of Biology Leiden, Plant Sciences, Sylviusweg 72, 2333 BE Leiden, The Netherlands
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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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Ménard D, Blaschek L, Kriechbaum K, Lee CC, Serk H, Zhu C, Lyubartsev A, Nuoendagula , Bacsik Z, Bergström L, Mathew A, Kajita S, Pesquet E. Plant biomechanics and resilience to environmental changes are controlled by specific lignin chemistries in each vascular cell type and morphotype. THE PLANT CELL 2022; 34:koac284. [PMID: 36215679 PMCID: PMC9709985 DOI: 10.1093/plcell/koac284] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 09/11/2022] [Indexed: 05/12/2023]
Abstract
The biopolymer lignin is deposited in the cell walls of vascular cells and is essential for long-distance water conduction and structural support in plants. Different vascular cell types contain distinct and conserved lignin chemistries, each with specific aromatic and aliphatic substitutions. Yet, the biological role of this conserved and specific lignin chemistry in each cell type remains unclear. Here, we investigated the roles of this lignin biochemical specificity for cellular functions by producing single cell analyses for three cell morphotypes of tracheary elements, which all allow sap conduction but differ in their morphology. We determined that specific lignin chemistries accumulate in each cell type. Moreover, lignin accumulated dynamically, increasing in quantity and changing in composition, to alter the cell wall biomechanics during cell maturation. For similar aromatic substitutions, residues with alcohol aliphatic functions increased stiffness whereas aldehydes increased flexibility of the cell wall. Modifying this lignin biochemical specificity and the sequence of its formation impaired the cell wall biomechanics of each morphotype and consequently hindered sap conduction and drought recovery. Together, our results demonstrate that each sap-conducting vascular cell type distinctly controls their lignin biochemistry to adjust their biomechanics and hydraulic properties to face developmental and environmental constraints.
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Affiliation(s)
- Delphine Ménard
- Department of Ecology, Environment and Plant Sciences (DEEP), Stockholm University, 106 91 Stockholm, Sweden
- Umeå Plant Science Centre (UPSC), Department of Plant Physiology, Umeå University, 901 87 Umeå, Sweden
| | - Leonard Blaschek
- Department of Ecology, Environment and Plant Sciences (DEEP), Stockholm University, 106 91 Stockholm, Sweden
| | - Konstantin Kriechbaum
- Department of Materials and Environmental Chemistry (MMK), Stockholm University, 106 91 Stockholm, Sweden
| | - Cheng Choo Lee
- Umeå Core Facility for Electron Microscopy (UCEM), Umeå University, 901 87 Umeå, Sweden
| | - Henrik Serk
- Umeå Plant Science Centre (UPSC), Department of Plant Physiology, Umeå University, 901 87 Umeå, Sweden
| | - Chuantao Zhu
- Department of Materials and Environmental Chemistry (MMK), Stockholm University, 106 91 Stockholm, Sweden
| | - Alexander Lyubartsev
- Department of Materials and Environmental Chemistry (MMK), Stockholm University, 106 91 Stockholm, Sweden
| | - Nuoendagula
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Tokyo 184-8588, Japan
| | - Zoltán Bacsik
- Department of Materials and Environmental Chemistry (MMK), Stockholm University, 106 91 Stockholm, Sweden
| | - Lennart Bergström
- Department of Materials and Environmental Chemistry (MMK), Stockholm University, 106 91 Stockholm, Sweden
| | - Aji Mathew
- Department of Materials and Environmental Chemistry (MMK), Stockholm University, 106 91 Stockholm, Sweden
| | - Shinya Kajita
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Tokyo 184-8588, Japan
| | - Edouard Pesquet
- Department of Ecology, Environment and Plant Sciences (DEEP), Stockholm University, 106 91 Stockholm, Sweden
- Umeå Plant Science Centre (UPSC), Department of Plant Physiology, Umeå University, 901 87 Umeå, Sweden
- Bolin Centre for Climate Research, Stockholm University, 106 91 Stockholm, Sweden
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Dória LC, Sonsin-Oliveira J, Rossi S, Marcati CR. Functional trade-offs in volume allocation to xylem cell types in 75 species from the Brazilian savanna Cerrado. ANNALS OF BOTANY 2022; 130:445-456. [PMID: 35863898 PMCID: PMC9486921 DOI: 10.1093/aob/mcac095] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 07/20/2022] [Indexed: 05/13/2023]
Abstract
BACKGROUND AND AIMS Xylem is a crucial tissue for plant survival, performing the functions of water transport, mechanical support and storage. Functional trade-offs are a result of the different assemblages of xylem cell types within a certain wood volume. We assessed how the volume allocated to different xylem cell types can be associated with wood functional trade-offs (hydraulics, mechanical and storage) in species from the Cerrado, the Brazilian savanna. We also assessed the xylem anatomical characters linked to wood density across species. METHODS We analysed cross-sections of branches collected from 75 woody species belonging to 42 angiosperm families from the Cerrado. We estimated the wood volume fraction allocated to different cell types and performed measurements of vessel diameter and wood density. KEY RESULTS The largest volume of wood is allocated to fibres (0.47), followed by parenchyma (0.33) and vessels (0.20). Wood density is positively correlated to cell wall (fibre and vessel wall), and negatively to the fractions of fibre lumen and gelatinous fibres. We observed a trade-off between hydraulics (vessel diameter) and mechanics (cell wall fraction), and between mechanics and storage (parenchyma fraction). The expected positive functional relationships between hydraulics (vessel diameter) and water and carbohydrate storage (parenchyma and fibre lumen fractions) were not detected, though larger vessels are linked to a larger wood volume allocated to gelatinous fibres. CONCLUSIONS Woody species from the Cerrado show evidence of functional trade-offs between water transport, mechanical support and storage. Gelatinous fibres might be potentially linked to water storage and release by their positive relationship to increased vessel diameter, thus replacing the functional role of parenchyma and fibre lumen cells. Species can profit from the increased mechanical strength under tension provided by the presence of gelatinous fibres, avoiding expensive investments in high wood density.
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Affiliation(s)
| | - Julia Sonsin-Oliveira
- Departamento de Biologia Vegetal, Programa de Pós-Graduação em Botânica, Instituto de Ciências Biológicas, Universidade de Brasilia (UnB), Brasília, DF, Brazil
| | - Sergio Rossi
- Département des Sciences Fondamentales, Université du Québec à Chicoutimi, Chicoutimi, QC, Canada
| | - Carmen Regina Marcati
- Departamento de Ciência Florestal, Solos e Ambiente, Universidade Estadual Paulista (UNESP), Faculdade de Ciências Agronômicas, Avenida Universitária, Botucatu, SP, Brazil
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Meng L, Zhang X, Wang L, Liu H, Zhao Y, Yi K, Cui G, Yin X. Transcriptome profiling unveils the mechanism of phenylpropane biosynthesis in rhizome development of Caucasian clover. PLoS One 2021; 16:e0254669. [PMID: 34255805 PMCID: PMC8277049 DOI: 10.1371/journal.pone.0254669] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 06/30/2021] [Indexed: 11/18/2022] Open
Abstract
Caucasian clover is the only perennial herb of the genus Leguminous clover with underground rhizomes. However, we know very little about its development process and mechanism. Transcriptome studies were conducted on the roots of Caucasian clover without a rhizome (NR) at the young seedling stage and the fully developed rhizome, including the root neck (R1), main root (R2), horizontal root (R3), and rhizome bud (R4), of the tissues in the mature phase. Compared with the rhizome in the mature phase, NR had 893 upregulated differentially expressed genes (DEGs), most of which were enriched in 'phenylpropanoid biosynthesis', 'phenylalanine metabolism', 'DNA replication' and 'biosynthesis of amino acids'. A higher number of transcription factors (AP2/ERF, C2H2 and FAR1) were found in NR. There were highly expressed genes for R4, such as auxin response factor SAUR, galacturonosyltransferase (GAUT), and sucrose synthase (SUS). Phenylpropanoids are very important for the entire process of rhizome development. We drew a cluster heat map of genes related to the phenylpropanoid biosynthesis pathway, in which the largest number of genes belonged to COMT, and most of them were upregulated in R4.
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Affiliation(s)
- Lingdong Meng
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, China
| | - Xiaomeng Zhang
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, China
| | - Lina Wang
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, China
| | - Haoyue Liu
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, China
| | - Yihang Zhao
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, China
| | - Kun Yi
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, China
| | - Guowen Cui
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, China
| | - Xiujie Yin
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, China
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Gutierrez Lopez J, Tor-Ngern P, Oren R, Kozii N, Laudon H, Hasselquist NJ. How tree species, tree size, and topographical location influenced tree transpiration in northern boreal forests during the historic 2018 drought. GLOBAL CHANGE BIOLOGY 2021; 27:3066-3078. [PMID: 33949757 DOI: 10.1111/gcb.15601] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 02/26/2021] [Accepted: 03/02/2021] [Indexed: 06/12/2023]
Abstract
Trees in northern latitude ecosystems are projected to experience increasing drought stress as a result of rising air temperatures and changes in precipitation patterns in northern latitude ecosystems. However, most drought-related studies on high-latitude boreal forests (>50°N) have been conducted in North America, with few studies quantifying the response in European and Eurasian boreal forests. Here, we tested how daily whole-tree transpiration (Q, Liters day-1 ) and Q normalized for mean daytime vapor pressure deficit (QDZ , Liters day-1 kPa-1 ) were affected by the historic 2018 drought in Europe. More specifically, we examined how tree species, size, and topographic position affected drought response in high-latitude mature boreal forest trees. We monitored 30 Pinus sylvestris (pine) and 30 Picea abies (spruce) trees distributed across a topographic gradient in northern Sweden. In general, pine showed a greater QDZ control compared to spruce during periods of severe drought (standardized precipitation-evapotranspiration index: SPEI < -1.5), suggesting that the latter are more sensitive to drought. Overall, QDZ reductions (using non-drought QDZ as reference) were less pronounced in larger trees during severe drought, but there was a species-specific pattern: QDZ reductions were greater in pine trees at high elevations and greater in spruce trees at lower elevations. Despite lower QDZ during severe drought, drought spells were interspersed with small precipitation events and overcast conditions, and QDZ returned to pre-drought conditions relatively quickly. This study highlights unique species-specific responses to drought, which are additionally driven by a codependent interaction among tree size, relative topographic position, and unique regional climate conditions.
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Affiliation(s)
- Jose Gutierrez Lopez
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Pantana Tor-Ngern
- Department of Environmental Science, Chulalongkorn University, Bangkok, Thailand
- Environment, Health and Social Data Analytics Research Group, Chulalongkorn University, Bangkok, Thailand
- Water Science and Technology for Sustainable Environment Research Group, Chulalongkorn University, Bangkok, Thailand
| | - Ram Oren
- Division of Environmental Science & Policy, Nicholas School of the Environment, Duke University, Durham, NC, USA
- Department of Forest Science, University of Helsinki, Helsinki, Finland
| | - Nataliia Kozii
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Hjalmar Laudon
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Niles J Hasselquist
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
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Song Z, Wang D, Gao Y, Li C, Jiang H, Zhu X, Zhang H. Changes of lignin biosynthesis in tobacco leaves during maturation. FUNCTIONAL PLANT BIOLOGY : FPB 2021; 48:624-633. [PMID: 33648626 DOI: 10.1071/fp20244] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 02/11/2021] [Indexed: 06/12/2023]
Abstract
Lignin is one of the most valuable renewable industrial materials. To elucidate the mechanism via which lignin is synthesised, we compared the lignin content, leaf hardness, cell wall thickness of palisade tissue, and gene expression patterns of lignin biosynthetic enzymes in three tobacco (Nicotiana tabacum L.) varieties during maturation. The results consistently showed that during maturation, the accumulation of lignin gradually increased in tobacco leaves, reaching a peak at full maturity (45 days after topping), and then gradually decreased. Similarly, the transcript level analysis revealed that the gene expression pattern of NtPAL, NtC4H, NtCCoAOMT and NtCOMT were relatively high, and consistent with the lignin content changes. Thus, the four genes may play regulatory roles in the synthesis of tobacco lignin. Analysis of tissue expression patterns of the lignin synthesis-related gene showed that the NtPAL, NtC4H, Nt4CL, NtHCT, NtCCoAOMT, NtCOMT, NtCCR, NtCAD, and NtPAO were all expressed in stems, roots, and leaves. NtC3H and NtF5H were specifically expressed in stems and roots, and not in leaves. Consistently, the NtC3H promoter induced high GUS expression in stems and petioles, marginal in roots, and no GUS activity in leaves. These results provide insights into molecular regulation of lignin biosynthesis in tobacco.
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Affiliation(s)
- Zhaopeng Song
- Key Laboratory for Cultivation of Tobacco Industry, College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, China
| | - Daibin Wang
- China Tobacco Chongqing Industrial Co., Ltd, Chongqing 400715, China
| | - Yabei Gao
- Key Laboratory for Cultivation of Tobacco Industry, College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, China
| | - Changjun Li
- China Tobacco Chongqing Industrial Co., Ltd, Chongqing 400715, China
| | - Houlong Jiang
- China Tobacco Chongqing Industrial Co., Ltd, Chongqing 400715, China
| | - Xiaowei Zhu
- China Tobacco Chongqing Industrial Co., Ltd, Chongqing 400715, China
| | - Hongying Zhang
- Key Laboratory for Cultivation of Tobacco Industry, College of Tobacco Science, Henan Agricultural University, Zhengzhou 450002, China; and Corresponding author.
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11
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Prendin AL, Carrer M, Bjerregaard Pedersen N, Normand S, Hollesen J, Treier UA, Pividori M, Garbrecht Thygesen L. Chemical signature of Eurois occulta L. outbreaks in the xylem cell wall of Salix glauca L. in Greenland. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 764:144607. [PMID: 33387770 DOI: 10.1016/j.scitotenv.2020.144607] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 11/29/2020] [Accepted: 12/17/2020] [Indexed: 06/12/2023]
Abstract
Insect defoliations are a major natural disturbance in high-latitude ecosystems and are expected to increase in frequency and severity due to current climatic change. Defoliations cause severe reductions in biomass and carbon investments that affect the functioning and productivity of tundra ecosystems. Here we combined dendro-anatomical analysis with chemical imaging to investigate the direct and lagged effects of insect outbreaks on carbon investment. We analysed the content of lignin vs. holocellulose, i.e. unspecified carbohydrates in xylem samples of Salix glauca L. collected at Iffiartarfik, Nuuk fjord, Greenland, featuring two outbreak events of the moth Eurois occulta L. Cross sections of the growth rings corresponding to both outbreaks ±3 years were analysed using confocal Raman imaging to identify possible chemical signatures related to insect defoliation on fibres, vessels, and ray parenchyma cells and to get insight into species-specific defence responses. Outbreak years with narrower rings and thinner fibre cell walls are accompanied by a change in the content of cell-wall polymers but not their underlying chemistry. Indeed, during the outbreaks the ratio between lignin and carbohydrates significantly increased in fibre but not vessel cell walls due to an increase in lignin content coupled with a reduced content of carbohydrates. Parenchyma cell walls and cell corners did not show any significant changes in the cell-wall biopolymer content. The selective adjustment of the cell-wall composition of fibres but not vessels under stressful conditions could be related to the plants priority to maintain an efficient hydraulic system rather than mechanical support. However, the higher lignin content of fibre cell walls formed during the outbreak events could increase mechanical stiffness to the thin walls by optimizing the available resources. Chemical analysis of xylem traits with Raman imaging is a promising approach to highlight hidden effects of defoliation otherwise overlooked with classical dendroecological methods.
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Affiliation(s)
- Angela Luisa Prendin
- University of Padova, TeSAF Department, Agripolis, Viale dell'Università, 16, 35020 Legnaro, PD, Italy; Aarhus University, Department of Biology, Ecoinformatics and Biodiversity, Ny Munkegade 116, building 1540, 8000 Aarhus C, Denmark.
| | - Marco Carrer
- University of Padova, TeSAF Department, Agripolis, Viale dell'Università, 16, 35020 Legnaro, PD, Italy.
| | | | - Signe Normand
- Aarhus University, Department of Biology, Ecoinformatics and Biodiversity, Ny Munkegade 116, building 1540, 8000 Aarhus C, Denmark; Center for Biodiversity Dynamics in a Changing World (BIOCHANGE), Department of Biology, Aarhus University, Ny Munkegade 116, building 1540, 8000 Aarhus C, Denmark.
| | - Jørgen Hollesen
- The National Museum of Denmark, Environmental Archaeology and Material Science, IC Modewegsvej, Brede, 2800 Kgs. Lyngby, Denmark.
| | - Urs Albert Treier
- Aarhus University, Department of Biology, Ecoinformatics and Biodiversity, Ny Munkegade 116, building 1540, 8000 Aarhus C, Denmark; Center for Biodiversity Dynamics in a Changing World (BIOCHANGE), Department of Biology, Aarhus University, Ny Munkegade 116, building 1540, 8000 Aarhus C, Denmark.
| | - Mario Pividori
- University of Padova, TeSAF Department, Agripolis, Viale dell'Università, 16, 35020 Legnaro, PD, Italy.
| | - Lisbeth Garbrecht Thygesen
- University of Copenhagen, Faculty of Science, Department of Geosciences and Natural Resource Management, Rolighedsvej 23, 1958 Frederiksberg C, Denmark.
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12
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Coleman HD, Brunner AM, Tsai CJ. Synergies and Entanglement in Secondary Cell Wall Development and Abiotic Stress Response in Trees. FRONTIERS IN PLANT SCIENCE 2021; 12:639769. [PMID: 33815447 PMCID: PMC8018706 DOI: 10.3389/fpls.2021.639769] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 03/01/2021] [Indexed: 06/12/2023]
Abstract
A major challenge for sustainable food, fuel, and fiber production is simultaneous genetic improvement of yield, biomass quality, and resilience to episodic environmental stress and climate change. For Populus and other forest trees, quality traits involve alterations in the secondary cell wall (SCW) of wood for traditional uses, as well as for a growing diversity of biofuels and bioproducts. Alterations in wood properties that are desirable for specific end uses can have negative effects on growth and stress tolerance. Understanding of the diverse roles of SCW genes is necessary for the genetic improvement of fast-growing, short-rotation trees that face perennial challenges in their growth and development. Here, we review recent progress into the synergies and antagonisms of SCW development and abiotic stress responses, particularly, the roles of transcription factors, SCW biogenesis genes, and paralog evolution.
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Affiliation(s)
| | - Amy M. Brunner
- Department of Forest Resources and Environmental Conservation, Virginia Tech, Blacksburg, VA, United States
| | - Chung-Jui Tsai
- Department of Plant Biology, University of Georgia, Athens, GA, United States
- Department of Genetics, University of Georgia, Athens, GA, United States
- Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, United States
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13
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Huang S, Zhou J, Gao L, Tang Y. Plant miR397 and its functions. FUNCTIONAL PLANT BIOLOGY : FPB 2021; 48:361-370. [PMID: 33333000 DOI: 10.1071/fp20342] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 11/23/2020] [Indexed: 06/12/2023]
Abstract
MicroRNAs (miRNAs) are noncoding, small RNAs of 20-24 nucleotides (nt) and function critically at the post-transcriptional level to regulate gene expression through cleaving mRNA targets or interfering with translation of the target mRNAs. They are broadly involved in many biological processes in plants. The miR397 family in plants contains several conserved members either in 21-nt or in 22-nt that mainly target the laccase (LAC) genes functioning in lignin synthesis and are involved in the development of plants under various conditions. Recent findings showed that miR397b in Arabidopsis could also target to Casein Kinase II Subunit Beta 3 (CKB3) and mediate circadian regulation and plant flowering. This review aims to summarise recent updates on miR397 and provides the available basis for understanding the functional mechanisms of miR397 in plant growth and development regulation and in response to external adverse stimulation.
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Affiliation(s)
- Shili Huang
- Guangdong Provincial Key Laboratory for Plant Epigenetics, Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Longhua Institute of Innovative Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, Guangdong province, China
| | - Jiajie Zhou
- Guangdong Provincial Key Laboratory for Plant Epigenetics, Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Longhua Institute of Innovative Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, Guangdong province, China
| | - Lei Gao
- Guangdong Provincial Key Laboratory for Plant Epigenetics, Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Longhua Institute of Innovative Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, Guangdong province, China
| | - Yulin Tang
- Guangdong Provincial Key Laboratory for Plant Epigenetics, Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Longhua Institute of Innovative Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, Guangdong province, China; and Corresponding author.
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14
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Bonetti S, Breitenstein D, Fatichi S, Domec JC, Or D. Persistent decay of fresh xylem hydraulic conductivity varies with pressure gradient and marks plant responses to injury. PLANT, CELL & ENVIRONMENT 2021; 44:371-386. [PMID: 32964494 DOI: 10.1111/pce.13893] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 09/02/2020] [Accepted: 09/07/2020] [Indexed: 05/29/2023]
Abstract
Defining plant hydraulic traits is central to the quantification of ecohydrological processes ranging from land-atmosphere interactions, to tree mortality and water-carbon budgets. A key plant trait is the xylem specific hydraulic conductivity (Kx ), that describes the plant's vascular system capacity to transport water. While xylem's vessels and tracheids are dead upon maturity, the xylem is neither inert nor deadwood, various components of the sapwood and surrounding tissue remaining alive and functional. Moreover, the established definition of Kx assumes linear relations between water flux and pressure gradient by tacitly considering the xylem as a "passive conduit". Here, we re-examine this notion of an inert xylem by systematically characterizing xylem flow in several woody plants using Kx measurements under constant and cyclic pressure gradients. Results show a temporal and pressure gradient dependence of Kx . Additionally, microscopic features in "living branches" are irreversibly modified upon drying of the xylem, thus differentiating the macroscopic definition of Kx for living and dead xylem. The findings highlight the picture of the xylem as a complex and delicate conductive system whose hydraulic behaviour transcends a passive gradient-based flow. The study sheds new light on xylem conceptualization, conductivity measurement protocols, in situ long-distance water transport and ecosystem modelling.
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Affiliation(s)
- Sara Bonetti
- Institute for Sustainable Resources, Bartlett School of Environment, Energy and Resources, University College London, London, UK
- Soil and Terrestrial Environmental Physics, Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | - Daniel Breitenstein
- Soil and Terrestrial Environmental Physics, Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | - Simone Fatichi
- Institute of Environmental Engineering, ETH Zurich, Zürich, Switzerland
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore
| | - Jean-Christophe Domec
- Bordeaux Sciences Agro, UMR 1391 INRA ISPA, Gradignan Cedex, France
- Nicholas School of the Environment, Duke University, Durham, North Carolina, USA
| | - Dani Or
- Soil and Terrestrial Environmental Physics, Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
- Division of Hydrologic Sciences, Desert Research Institute, Reno, Nevada, USA
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15
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Kitin P, Nakaba S, Hunt CG, Lim S, Funada R. Direct fluorescence imaging of lignocellulosic and suberized cell walls in roots and stems. AOB PLANTS 2020; 12:plaa032. [PMID: 32793329 PMCID: PMC7415075 DOI: 10.1093/aobpla/plaa032] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 06/21/2020] [Indexed: 05/05/2023]
Abstract
Investigating plant structure is fundamental in botanical science and provides crucial knowledge for the theories of plant evolution, ecophysiology and for the biotechnological practices. Modern plant anatomy often targets the formation, localization and characterization of cellulosic, lignified or suberized cell walls. While classical methods developed in the 1960s are still popular, recent innovations in tissue preparation, fluorescence staining and microscopy equipment offer advantages to the traditional practices for investigation of the complex lignocellulosic walls. Our goal is to enhance the productivity and quality of microscopy work by focusing on quick and cost-effective preparation of thick sections or plant specimen surfaces and efficient use of direct fluorescent stains. We discuss popular histochemical microscopy techniques for visualization of cell walls, such as autofluorescence or staining with calcofluor, Congo red (CR), fluorol yellow (FY) and safranin, and provide detailed descriptions of our own approaches and protocols. Autofluorescence of lignin in combination with CR and FY staining can clearly differentiate between lignified, suberized and unlignified cell walls in root and stem tissues. Glycerol can serve as an effective clearing medium as well as the carrier of FY for staining of suberin and lipids allowing for observation of thick histological preparations. Three-dimensional (3D) imaging of all cell types together with chemical information by wide-field fluorescence or confocal laser scanning microscopy (CLSM) was achieved.
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Affiliation(s)
- Peter Kitin
- School of Environmental and Forest Sciences, University of Washington, Seattle, WA, USA
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Fuchu-Tokyo, Japan
| | - Satoshi Nakaba
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Fuchu-Tokyo, Japan
- Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu-Tokyo, Japan
| | | | - Sierin Lim
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore
| | - Ryo Funada
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Fuchu-Tokyo, Japan
- Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu-Tokyo, Japan
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16
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Khandal H, Singh AP, Chattopadhyay D. The MicroRNA397b -LACCASE2 Module Regulates Root Lignification under Water and Phosphate Deficiency. PLANT PHYSIOLOGY 2020; 182:1387-1403. [PMID: 31949029 PMCID: PMC7054887 DOI: 10.1104/pp.19.00921] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 01/07/2020] [Indexed: 05/18/2023]
Abstract
Deficiency of water and phosphate induce lignin deposition in roots. LACCASEs, a family of cell wall-localized multicopper oxidases, are involved in lignin biosynthesis. We demonstrate here that LACCASE2 (LAC2) acts as a negative regulator of lignin deposition in root vascular tissues during water deficit. An Arabidopsis (Arabidopsis thaliana) transfer DNA insertion mutant of LAC2 displayed a short primary root and high lignin deposition in root vascular tissues. However, restoration of LAC2 expression rescued these phenotypes. LAC2 expression was significantly down-regulated under water deficit and posttranscriptionally regulated by microRNA397b (miR397b) in roots under normal and water-deficit conditions. Down-regulation of miR397b activity increased LAC2 expression and root length, and decreased lignin content in root vasculature. Similarly, phosphate (Pi) deficiency inversely affected miR397b and LAC2 expression. Lignin deposition in the root elongation zone under Pi-limited conditions was dependent on LAC2 expression. Localized iron accumulation and callose deposition in the root elongation zone under Pi deficiency increased with LAC2-dependent lignification, suggesting a direct relationship between these processes. Our study reveals a regulatory role for the miR397b-LAC2 module in root lignification during water and phosphate deficiency.
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Affiliation(s)
- Hitaishi Khandal
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Amar Pal Singh
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Debasis Chattopadhyay
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
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17
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Sakamoto S, Kamimura N, Tokue Y, Nakata MT, Yamamoto M, Hu S, Masai E, Mitsuda N, Kajita S. Identification of enzymatic genes with the potential to reduce biomass recalcitrance through lignin manipulation in Arabidopsis. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:97. [PMID: 32514309 PMCID: PMC7260809 DOI: 10.1186/s13068-020-01736-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 04/09/2020] [Indexed: 05/09/2023]
Abstract
BACKGROUND During the chemical and biochemical decomposition of lignocellulosic biomasses, lignin is highly recalcitrant. Genetic transformation of plants to qualitatively and/or quantitatively modify lignin may reduce these recalcitrant properties. Efficient discovery of genes to achieve lignin manipulation is thus required. RESULTS To screen for new genes to reduce lignin recalcitrance, we heterologously expressed 50 enzymatic genes under the control of a cinnamate 4-hydroxylase (C4H) gene promoter, derived from a hybrid aspen, which is preferentially active in tissues with lignified cell walls in Arabidopsis plants. These genes encode enzymes that act on metabolites in shikimate, general phenylpropanoid, flavonoid, or monolignol biosynthetic pathways. Among these genes, 30, 18, and 2 originated from plants, bacteria, and fungi, respectively. In our first screening step, 296 independent transgenic plants (T1 generation) harboring single or multiple transgenes were generated from pools of seven Agrobacterium strains used for conventional floral-dip transformation. Wiesner and Mäule staining patterns in the stems of the resultant plants revealed seven and nine plants with apparent abnormalities in the two respective staining analyses. According to genomic PCR and subsequent direct sequencing, each of these 16 plants possessed a gene encoding either coniferaldehyde dehydrogenase (calB), feruloyl-CoA 6'-hydroxylase (F6H1), hydroxycinnamoyl-CoA hydratase/lyase (couA), or ferulate 5-hydroxylase (F5H), with one transgenic plant carrying both calB and F6H1. The effects of these genes on lignin manipulation were confirmed in individually re-created T1 transgenic Arabidopsis plants. While no difference in lignin content was detected in the transgenic lines compared with the wild type, lignin monomeric composition was changed in the transgenic lines. The observed compositional change in the transgenic plants carrying calB, couA, and F5H led to improved sugar release from cell walls after alkaline pretreatment. CONCLUSIONS Simple colorimetric characterization of stem lignin is useful for simultaneous screening of many genes with the potential to reduce lignin recalcitrance. In addition to F5H, the positive control, we identified three enzyme-coding genes that can function as genetic tools for lignin manipulation. Two of these genes (calB and couA) accelerate sugar release from transgenic lignocelluloses.
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Affiliation(s)
- Shingo Sakamoto
- Plant Gene Regulation Research Group, Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8566 Japan
| | - Naofumi Kamimura
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188 Japan
| | - Yosuke Tokue
- Plant Gene Regulation Research Group, Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8566 Japan
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188 Japan
| | - Miyuki T. Nakata
- Plant Gene Regulation Research Group, Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8566 Japan
- Present Address: Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara 630-0192 Japan
| | - Masanobu Yamamoto
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 Japan
| | - Shi Hu
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 Japan
| | - Eiji Masai
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188 Japan
| | - Nobutaka Mitsuda
- Plant Gene Regulation Research Group, Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8566 Japan
| | - Shinya Kajita
- Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 Japan
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18
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Dória LC, Meijs C, Podadera DS, Del Arco M, Smets E, Delzon S, Lens F. Embolism resistance in stems of herbaceous Brassicaceae and Asteraceae is linked to differences in woodiness and precipitation. ANNALS OF BOTANY 2019; 124:1-14. [PMID: 30590483 PMCID: PMC6676380 DOI: 10.1093/aob/mcy233] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 12/05/2018] [Indexed: 05/16/2023]
Abstract
BACKGROUND AND AIMS Plant survival under extreme drought events has been associated with xylem vulnerability to embolism (the disruption of water transport due to air bubbles in conduits). Despite the ecological and economic importance of herbaceous species, studies focusing on hydraulic failure in herbs remain scarce. Here, we assess the vulnerability to embolism and anatomical adaptations in stems of seven herbaceous Brassicaceae species occurring in different vegetation zones of the island of Tenerife, Canary Islands, and merged them with a similar hydraulic-anatomical data set for herbaceous Asteraceae from Tenerife. METHODS Measurements of vulnerability to xylem embolism using the in situ flow centrifuge technique along with light and transmission electron microscope observations were performed in stems of the herbaceous species. We also assessed the link between embolism resistance vs. mean annual precipitation and anatomical stem characters. KEY RESULTS The herbaceous species show a 2-fold variation in stem P50 from -2.1 MPa to -4.9 MPa. Within Hirschfeldia incana and Sisymbrium orientale, there is also a significant stem P50 difference between populations growing in contrasting environments. Variation in stem P50 is mainly explained by mean annual precipitation as well as by the variation in the degree of woodiness (calculated as the proportion of lignified area per total stem area) and to a lesser extent by the thickness of intervessel pit membranes. Moreover, mean annual precipitation explains the total variance in embolism resistance and stem anatomical traits. CONCLUSIONS The degree of woodiness and thickness of intervessel pit membranes are good predictors of embolism resistance in the herbaceous Brassicaceae and Asteraceae species studied. Differences in mean annual precipitation across the sampling sites affect embolism resistance and stem anatomical characters, both being important characters determining survival and distribution of the herbaceous eudicots.
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Affiliation(s)
| | - Cynthia Meijs
- Naturalis Biodiversity Center, Leiden University, RA Leiden, The Netherlands
| | | | - Marcelino Del Arco
- Department of Plant Biology (Botany), La Laguna University, La Laguna, Tenerife, Spain
| | - Erik Smets
- Naturalis Biodiversity Center, Leiden University, RA Leiden, The Netherlands
| | | | - Frederic Lens
- Naturalis Biodiversity Center, Leiden University, RA Leiden, The Netherlands
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19
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North GB, Brinton EK, Browne MG, Gillman MG, Roddy AB, Kho TL, Wang E, Fung VA, Brodersen CR. Hydraulic conductance, resistance, and resilience: how leaves of a tropical epiphyte respond to drought. AMERICAN JOURNAL OF BOTANY 2019; 106:943-957. [PMID: 31294833 PMCID: PMC6852343 DOI: 10.1002/ajb2.1323] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 05/06/2019] [Indexed: 05/05/2023]
Abstract
PREMISE Because of its broad range in the neotropical rainforest and within tree canopies, the tank bromeliad Guzmania monostachia was investigated as a model of how varying leaf hydraulic conductance (Kleaf ) could help plants resist and recover from episodic drought. The two pathways of Kleaf , inside and outside the xylem, were also examined to determine the sites and causes of major hydraulic resistances within the leaf. METHODS We measured leaf hydraulic conductance for plants in the field and laboratory under wet, dry, and rewetted conditions and applied physiological, anatomical, and gene expression analysis with modeling to investigate changes in Kleaf . RESULTS After 7 d with no rain in the field or 14 days with no water in the glasshouse, Kleaf decreased by 50% yet increased to hydrated values within 4 d of tank refilling. Staining to detect embolism combined with modeling indicated that changes outside the xylem were of greater importance to Kleaf than were changes inside the xylem and were associated with changes in intercellular air spaces (aerenchyma), aquaporin expression and inhibition, and cuticular conductance. CONCLUSIONS Low values for all conductances during drying, particularly in pathways outside the xylem, lead to hydraulic resilience for this species and may also contribute to its broad environmental tolerances.
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Affiliation(s)
| | | | - Marvin G. Browne
- Department of Ecology and Evolutionary BiologyUniversity of CaliforniaLos AngelesCAUSA
| | | | - Adam B. Roddy
- School of Forestry & Environmental StudiesYale UniversityNew HavenCTUSA
| | - Tiffany L. Kho
- Biology DepartmentUniversity of San FranciscoSan FranciscoCAUSA
| | - Emily Wang
- Department of BiologyOccidental CollegeLos AngelesCAUSA
| | - Vitor A. Fung
- Department of BiotechnologyJohns Hopkins UniversityBaltimoreMDUSA
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20
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Hu JQ, Qi Q, Zhao YL, Tian XM, Lu H, Gai Y, Jiang XN. Unraveling the impact of Pto4CL1 regulation on the cell wall components and wood properties of perennial transgenic Populus tomentosa. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2019; 139:672-680. [PMID: 31054469 DOI: 10.1016/j.plaphy.2019.03.035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 03/22/2019] [Accepted: 03/25/2019] [Indexed: 06/09/2023]
Abstract
Cell wall components and structure impact the physical and mechanical properties of plants, thereby affecting wood applications. Lignin is the most abundant biopolymer after cellulose in the wood cell wall and can be modified by certain lignin biosynthesis enzymes. 4-Coumarate: coenzyme A ligase(4CL) is an important lignin biosynthesis enzyme. To demonstrate the impact of the regulation of Pto4CL1 from poplar on wood properties, we analyzed the composition and anatomy of 5-year-old Pto4CL1-modified poplar cell walls, assessing the density, strength, volume shrinkage, and impact toughness of the transgenic trees. These results showed that the up-regulation of Pto4CL1 increased the lignin content to 46.65% from 33.11% in the control plants, while hydrophilic polysaccharides such as cellulose, hemi-cellulose, and pectin decreased. In contrast, the down-regulation of Pto4CL1 resulted in a reduction in lignin content to 27.39%, and the content of cellulose and hemi-cellulose showed compensatory variation. Raman spectroscopy showed that the change in lignin in the transgenic events was embodied in the deposition and concentration of lignin in the secondary cell wall. Moreover, the increased lignin content caused significantly increased wood strength and slightly increased wood density. In contrast, a reduction in lignin content resulted in a significant decrease in wood strength and a slight decrease in wood density. However, the Pto4CL1-modified trees had similar stiffness to the control group. We also found a significant decrease in volume shrinkage and increase in impact toughness in the low-lignin events. These results indicate that Pto4CL1 regulation alters the chemical composition of plant cell walls and these changes affect the physical and mechanical properties of the wood.
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Affiliation(s)
- Jia-Qi Hu
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, 100083, PR China
| | - Qi Qi
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, 100083, PR China
| | - Yan-Ling Zhao
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, 100083, PR China; Department of Chemical Engineering, Hua Qiao University, Xiamen, 361021, Fujian, PR China
| | - Xiao-Ming Tian
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, 100083, PR China
| | - Hai Lu
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, 100083, PR China
| | - Ying Gai
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, 100083, PR China; The Tree and Ornamental Plant Breeding and Biotechnology Laboratory of National Forestry and Grassland Administration, National Engineering Laboratory for Tree Breeding, Beijing, 100083, PR China.
| | - Xiang-Ning Jiang
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, 100083, PR China; The Tree and Ornamental Plant Breeding and Biotechnology Laboratory of National Forestry and Grassland Administration, National Engineering Laboratory for Tree Breeding, Beijing, 100083, PR China.
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21
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Gutierrez Lopez J, Licata J, Pypker T, Asbjornsen H. Effects of heater wattage on sap flux density estimates using an improved tree-cut experiment. TREE PHYSIOLOGY 2019; 39:679-693. [PMID: 30597089 DOI: 10.1093/treephys/tpy137] [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: 04/19/2018] [Revised: 11/11/2018] [Accepted: 11/22/2018] [Indexed: 06/09/2023]
Abstract
We assessed the effects of heater wattage on sap flux estimates from heat dissipation sensors and generated calibrated equations for 1-year-old Eucalyptus grandis Hill ex Maiden trees. We used a total of eight trees ranging from 3 to 6 cm in diameter. Our calibration experiment was performed with a modified tree-cut approach, which allowed us to estimate gravimetric water use manually weighing 20 l buckets every 15 min while sap flux was monitored on each tree. Our results indicate that changes the current supplied to the heaters from 0.15 to 0.25 W does not significantly influence sap flux estimates, as long as the maximum temperature (Tmax) is properly determined for each period when wattage is different, and natural temperature gradients are corrected. Using the original parameters developed for this method, sap flux density and sap flow had an average underestimation of 53%, which according to our analysis had a reduced but relevant correlation with tree diameter (R2 = 0.3, linear regression). These results may allow researchers to supply different currents to heat dissipation sensors to increase sensitivity or to reduce power consumption. They also provide evidence in favor of the correction and use of raw data collected when unwanted changes in wattage occur. The relationship observed between estimation error and tree diameter, while not strongly significant, suggests that diameter plays an important role in the estimation errors that has not been previously considered, and requires further research.
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Affiliation(s)
- Jose Gutierrez Lopez
- Earth Systems Research Center, University of New Hampshire, Durham, NH, USA
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå Sweden
| | - Julian Licata
- Institutional Research and Effectiveness, Bemidji State University, Bemidji, MN, USA
| | - Thomas Pypker
- Department of Natural Resource Sciences, Thompson Rivers University, Kamloops, BC, Canada
| | - Heidi Asbjornsen
- Earth Systems Research Center, University of New Hampshire, Durham, NH, USA
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22
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Hillabrand RM, Lieffers VJ, Hogg EH, Martínez-Sancho E, Menzel A, Hacke UG. Functional xylem anatomy of aspen exhibits greater change due to insect defoliation than to drought. TREE PHYSIOLOGY 2019; 39:45-54. [PMID: 29982833 DOI: 10.1093/treephys/tpy075] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 05/31/2018] [Indexed: 06/08/2023]
Abstract
The study of tree rings can reveal long-term records of a tree's response to the environment. This dendroecological approach, when supplemented with finer-scale observations of the xylem anatomy, can provide novel information about a tree's year-to-year anatomical and hydraulic adjustments. Here we use this method in aspen (Populus tremuloides Michx.) to identify xylem response to drought and insect defoliation. Surprisingly, we found that precipitation influenced vessel diameter mostly in the trees' youth, while this correlation was less pronounced at maturity. This is likely due to a reduction in stress the stand experiences as it ages, and reflects an ability to mediate drought stress as trees mature. Defoliation events caused consistent and profound changes in fiber anatomy likely leading to reduced structural support to vessels. We therefore expect that in years of defoliation trees may be vulnerable to drought-induced cavitation when leaf area recovers. This study highlights how the inclusion of cellular level measurements in tree ring studies provides additional information on how stress events may alter tree functioning through alterations in structure.
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Affiliation(s)
- R M Hillabrand
- University of Alberta, Department of Renewable Resources, 442 ESB, Edmonton, AB, Canada
| | - V J Lieffers
- University of Alberta, Department of Renewable Resources, 442 ESB, Edmonton, AB, Canada
| | - E H Hogg
- Natural Resources Canada, Canadian Forest Service, Edmonton, AB, Canada
| | - E Martínez-Sancho
- TUM School of Life Sciences, Ecoclimatology, Technical University of Munich, Freising, Germany
| | - A Menzel
- TUM School of Life Sciences, Ecoclimatology, Technical University of Munich, Freising, Germany
- Institute for Advanced Study, Technical University of Munich, Garching, Germany
| | - U G Hacke
- University of Alberta, Department of Renewable Resources, 442 ESB, Edmonton, AB, Canada
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23
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Tng DYP, Apgaua DMG, Ishida YF, Mencuccini M, Lloyd J, Laurance WF, Laurance SGW. Rainforest trees respond to drought by modifying their hydraulic architecture. Ecol Evol 2018; 8:12479-12491. [PMID: 30619559 PMCID: PMC6308889 DOI: 10.1002/ece3.4601] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 09/03/2018] [Accepted: 09/05/2018] [Indexed: 02/06/2023] Open
Abstract
Increased drought is forecasted for tropical regions, with severe implications for the health and function of forest ecosystems. How mature forest trees will respond to water deficit is poorly known. We investigated wood anatomy and leaf traits in lowland tropical forest trees after 24 months of experimental rainfall exclusion. Sampling sun-exposed young canopy branches from target species, we found species-specific systematic variation in hydraulic-related wood anatomy and leaf traits in response to drought stress. Relative to controls, drought-affected individuals of different tree species variously exhibited trait measures consistent with increasing hydraulic safety. These included narrower or less vessels, reduced vessel groupings, lower theoretical water conductivities, less water storage tissue and more abundant fiber in their wood, and more occluded vessels. Drought-affected individuals also had thinner leaves, and more negative pre-dawn or mid-day leaf water potentials. Future studies examining both wood and leaf hydraulic traits should improve the representation of plant hydraulics within terrestrial ecosystem and biosphere models, and help fine-tune predictions of how future climate changes will affect tropical forests globally.
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Affiliation(s)
- David Y. P. Tng
- Centre for Tropical, Environmental and Sustainability Sciences, College of Science and EngineeringJames Cook UniversitySmithfieldQueenslandAustralia
- Instituto de BiologiaUniversidade Federal da BahiaSalvadorBahiaBrazil
| | - Deborah M. G. Apgaua
- Centre for Tropical, Environmental and Sustainability Sciences, College of Science and EngineeringJames Cook UniversitySmithfieldQueenslandAustralia
| | - Yoko F. Ishida
- Centre for Tropical, Environmental and Sustainability Sciences, College of Science and EngineeringJames Cook UniversitySmithfieldQueenslandAustralia
| | - Maurizio Mencuccini
- ICREAPg. Lluís CompanysBarcelonaSpain
- CREAFUniversidad Autonoma de BarcelonaBarcelonaSpain
| | - Jon Lloyd
- Centre for Tropical, Environmental and Sustainability Sciences, College of Science and EngineeringJames Cook UniversitySmithfieldQueenslandAustralia
- Department of Life SciencesImperial College LondonAscotUK
- Faculdade de Filosofia, Ciencias e Letras de Ribeirao PretoUniversidade de Sao PauloRibeirao PretoBrazil
| | - William F. Laurance
- Centre for Tropical, Environmental and Sustainability Sciences, College of Science and EngineeringJames Cook UniversitySmithfieldQueenslandAustralia
| | - Susan G. W. Laurance
- Centre for Tropical, Environmental and Sustainability Sciences, College of Science and EngineeringJames Cook UniversitySmithfieldQueenslandAustralia
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24
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Vidot K, Gaillard C, Rivard C, Siret R, Lahaye M. Cryo-laser scanning confocal microscopy of diffusible plant compounds. PLANT METHODS 2018; 14:89. [PMID: 30344615 PMCID: PMC6186079 DOI: 10.1186/s13007-018-0356-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 10/08/2018] [Indexed: 05/22/2023]
Abstract
BACKGROUND The in vivo observation of diffusible components, such as ions and small phenolic compounds, remains a challenge in turgid plant organs. The analytical techniques used to localize such components in water-rich tissue with a large field of view are lacking. It remains an issue to limit compound diffusion during sample preparation and observation processes. RESULTS An experimental setup involving the infusion staining of plant tissue and the cryo-fixation and cryo-sectioning of tissue samples followed by fluorescence cryo-observation by laser scanning confocal microscopy (LSCM) was developed. This setup was successfully applied to investigate the structure of the apple fruit cortex and table grape berry and was shown to be relevant for localizing calcium, potassium and flavonoid compounds. CONCLUSION The cryo-approach was well adapted and opens new opportunities for imaging other diffusible components in hydrated tissues.
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Affiliation(s)
- Kevin Vidot
- UR 1268 Biopolymères Interactions Assemblages, INRA, 44300 Nantes, France
- USC 1422 GRAPPE, INRA, Ecole Supérieure d’Agricultures, SFR 4207 QUASAV, 55 rue Rabelais, 49100 Angers, France
| | - Cédric Gaillard
- UR 1268 Biopolymères Interactions Assemblages, INRA, 44300 Nantes, France
| | - Camille Rivard
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, 91192 Gif-Sur-Yvette Cedex, France
- UAR 1008 DPT CEPIA, INRA, 44300 Nantes, France
| | - René Siret
- USC 1422 GRAPPE, INRA, Ecole Supérieure d’Agricultures, SFR 4207 QUASAV, 55 rue Rabelais, 49100 Angers, France
| | - Marc Lahaye
- UR 1268 Biopolymères Interactions Assemblages, INRA, 44300 Nantes, France
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25
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Felhofer M, Prats-Mateu B, Bock P, Gierlinger N. Antifungal stilbene impregnation: transport and distribution on the micron-level. TREE PHYSIOLOGY 2018; 38:1526-1537. [PMID: 29992254 PMCID: PMC6198867 DOI: 10.1093/treephys/tpy073] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 05/17/2018] [Accepted: 06/03/2018] [Indexed: 05/04/2023]
Abstract
The transition from the living water-transporting sapwood to heartwood involves in many tree species impregnation with extractives. These differ in amount and composition, and enhance resistance against bacteria, insects or fungi. To understand the synthesis, transport and impregnation processes new insights into the biochemical processes are needed by in-situ methods. Here we show the extractive distribution in pine (Pinus sylvestris) microsections with a high lateral resolution sampled in a non-destructive manner using Confocal Raman Microscopy. Integrating marker bands of stilbenes and lipids enables to clearly track the rapid change from sapwood to heartwood within one tree ring. The higher impregnation of the cell corner, compound middle lamella, the S3 layer and pits reveals the optimization of decay resistance on the micron-level. Furthermore, deposits with changing chemical composition are elucidated in the rays and lumen of the tracheids. The spectral signature of these deposits shows the co-location of lipids and pinosylvins with changing ratios from the living to the dead tissue. The results demonstrate that the extractive impregnation on the micro- and nano-level is optimized by a symbiotic relationship of lipids and pinosylvins to enhance the tree's resistance and lifetime.
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Affiliation(s)
- Martin Felhofer
- Institute for Biophysics, Department of Nanobiotechnology, University of Natural Resources and Life Sciences, Muthgasse, Vienna, Austria
| | - Batirtze Prats-Mateu
- Institute for Biophysics, Department of Nanobiotechnology, University of Natural Resources and Life Sciences, Muthgasse, Vienna, Austria
| | - Peter Bock
- Institute for Biophysics, Department of Nanobiotechnology, University of Natural Resources and Life Sciences, Muthgasse, Vienna, Austria
| | - Notburga Gierlinger
- Institute for Biophysics, Department of Nanobiotechnology, University of Natural Resources and Life Sciences, Muthgasse, Vienna, Austria
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26
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Pratt RB, Jacobsen AL. Identifying which conduits are moving water in woody plants: a new HRCT-based method. TREE PHYSIOLOGY 2018; 38:1200-1212. [PMID: 29660094 DOI: 10.1093/treephys/tpy034] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Accepted: 03/07/2018] [Indexed: 06/08/2023]
Abstract
In vivo imaging methods are useful for examination of plant vascular tissues, particularly in the identification of fluid vs gas-filled conduits; however, these methods may not allow for the simple identification of conductive conduits. Our aim in the present study was to develop a method that would allow for the in vivo identification of conductive conduits. Intact plants and segments of grapevine (Vitis vinifera L.) and intact American chestnut (Castanea dentata (Marshall) Borkh.) saplings were examined. We found that iohexol, a water soluble iodine-rich molecule, was a useful contrast agent. We also stained the xylem of segments and gas- dried samples to compare between intact scans and excised segments. Iohexol could be readily fed through cut roots or stems into the transpiration stream, was successfully transported through the xylem and marked conductive vessels within high-resolution computed tomography (HRCT) scans. Iohexol results were comparable to those obtained by staining cut segments, with iohexol detecting greater numbers of smaller conduits in some samples. Samples contained gas-filled conduits, as well as both conductive (containing iohexol tracer) and non-conductive (no iohexol tracer) fluid-filled vessels. Fluid-filled non-conductive vessels were likely still developing or were not connected to the sap stream by a low resistance pathway. We found minimal differences between intact and excised segments other than excision-related dilution of iohexol. Both vessels and vasicentric tracheids were filled with iohexol in chestnut, providing a new tool to study the functions of these different cell types. The use of iohexol as a tracer to identify conductive vessels may greatly improve the utility of HRCT as a tool in the study of plant hydraulic function. Future studies using HRCT will likely need to incorporate conductive vessel markers or controls into experiments due to the presence of non-conductive fluid-filled vessels within the xylem.
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Affiliation(s)
- R Brandon Pratt
- Department of Biology, California State University, Bakersfield, 9001 Stockdale Hwy, Bakersfield, CA, USA
| | - Anna L Jacobsen
- Department of Biology, California State University, Bakersfield, 9001 Stockdale Hwy, Bakersfield, CA, USA
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27
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van den Berg N, Christie JB, Aveling TAS, Engelbrecht J. Callose and β-1,3-glucanase inhibit Phytophthora cinnamomi
in a resistant avocado rootstock. PLANT PATHOLOGY 2018; 67:1150-1160. [PMID: 0 DOI: 10.1111/ppa.12819] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Affiliation(s)
- N. van den Berg
- Forestry and Agricultural Biotechnology Institute (FABI); University of Pretoria; Pretoria 0002 South Africa
- Department of Microbiology and Plant Pathology; University of Pretoria; Pretoria 0002 South Africa
| | - J. B. Christie
- Forestry and Agricultural Biotechnology Institute (FABI); University of Pretoria; Pretoria 0002 South Africa
- Department of Microbiology and Plant Pathology; University of Pretoria; Pretoria 0002 South Africa
| | - T. A. S. Aveling
- Forestry and Agricultural Biotechnology Institute (FABI); University of Pretoria; Pretoria 0002 South Africa
- Department of Plant and Soil Sciences; University of Pretoria; Pretoria 0002 South Africa
| | - J. Engelbrecht
- Forestry and Agricultural Biotechnology Institute (FABI); University of Pretoria; Pretoria 0002 South Africa
- Department of Microbiology and Plant Pathology; University of Pretoria; Pretoria 0002 South Africa
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28
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Naik P, Wang JP, Sederoff R, Chiang V, Williams C, Ducoste JJ. Assessing the impact of the 4CL enzyme complex on the robustness of monolignol biosynthesis using metabolic pathway analysis. PLoS One 2018; 13:e0193896. [PMID: 29509777 PMCID: PMC5839572 DOI: 10.1371/journal.pone.0193896] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 02/19/2018] [Indexed: 11/18/2022] Open
Abstract
Lignin is a polymer present in the secondary cell walls of all vascular plants. It is a known barrier to pulping and the extraction of high-energy sugars from cellulosic biomass. The challenge faced with predicting outcomes of transgenic plants with reduced lignin is due in part to the presence of unique protein-protein interactions that influence the regulation and metabolic flux in the pathway. Yet, it is unclear why certain plants have evolved to create these protein complexes. In this study, we use mathematical models to investigate the role that the protein complex, formed specifically between Ptr4CL3 and Ptr4CL5 enzymes, have on the monolignol biosynthesis pathway. The role of this Ptr4CL3-Ptr4CL5 enzyme complex on the steady state flux distribution was quantified by performing Monte Carlo simulations. The effect of this complex on the robustness and the homeostatic properties of the pathway were identified by performing sensitivity and stability analyses, respectively. Results from these robustness and stability analyses suggest that the monolignol biosynthetic pathway is resilient to mild perturbations in the presence of the Ptr4CL3-Ptr4CL5 complex. Specifically, the presence of Ptr4CL3-Ptr4CL5 complex increased the stability of the pathway by 22%. The robustness in the pathway is maintained due to the presence of multiple enzyme isoforms as well as the presence of alternative pathways resulting from the presence of the Ptr4CL3-Ptr4CL5 complex.
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Affiliation(s)
- Punith Naik
- Civil, Construction, and Environmental Engineering, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Jack P. Wang
- Forest Biotechnology Group, Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Ronald Sederoff
- Forest Biotechnology Group, Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Vincent Chiang
- Forest Biotechnology Group, Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Cranos Williams
- Electrical and Computer Engineering, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Joel J. Ducoste
- Civil, Construction, and Environmental Engineering, North Carolina State University, Raleigh, North Carolina, United States of America
- * E-mail:
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29
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Jacobsen AL, Valdovinos-Ayala J, Pratt RB. Functional lifespans of xylem vessels: Development, hydraulic function, and post-function of vessels in several species of woody plants. AMERICAN JOURNAL OF BOTANY 2018; 105:142-150. [PMID: 29570215 DOI: 10.1002/ajb2.1029] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 10/31/2017] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY Xylem vessels transition through different stages during their functional lifespan, including expansion and development of vessel elements, transition to vessel hydraulic functionality, and eventual transition to post-functionality. We used information on vessel development and function to develop a model of vessel lifespan for woody plants. METHODS We examined vessel functional lifespan using repeated anatomical sampling throughout the growing season, combined with active-xylem staining to evaluate vessel hydraulic transport functionality. These data were combined with a literature review. The transitions between vessel functional lifespans for several species are illustrated, including grapevine (Vitis vinifera L., Vitaceae), English oak (Quercus robur L., Fagaceae), American chestnut [Castanea dentata (Marshall) Borkh.; Fagaceae], and several arid and semi-arid shrub species. KEY RESULTS In intact woody plants, development and maturation of vessel elements may be gradual. Once hydraulically functional, vessel elements connect to form a vessel network that is responsible for bulk hydraulic flow through the xylem. Vessels become nonfunctional due to the formation of gas emboli. In some species and under some conditions, vessel functionality of embolized conduits may be restored through refilling. Blockages, such as tyloses, gels, or gums, indicate permanent losses in hydraulic functional capacity; however, there may be some interesting exceptions to permanent loss of functionality for gel-based blockages. CONCLUSIONS The gradual development and maturation of vessel elements in woody plants, variation in the onset of functionality between different populations of vessels throughout the growing season, and differences in the timing of vessel transitions to post-functionality are important aspects of plant hydraulic function.
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Affiliation(s)
- Anna L Jacobsen
- Department of Biology, California State University, Bakersfield, 9001 Stockdale Hwy., Bakersfield, California, 93311, USA
| | - Jessica Valdovinos-Ayala
- Department of Biology, California State University, Bakersfield, 9001 Stockdale Hwy., Bakersfield, California, 93311, USA
| | - R Brandon Pratt
- Department of Biology, California State University, Bakersfield, 9001 Stockdale Hwy., Bakersfield, California, 93311, USA
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30
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Escamez S, Latha Gandla M, Derba-Maceluch M, Lundqvist SO, Mellerowicz EJ, Jönsson LJ, Tuominen H. A collection of genetically engineered Populus trees reveals wood biomass traits that predict glucose yield from enzymatic hydrolysis. Sci Rep 2017; 7:15798. [PMID: 29150693 PMCID: PMC5693926 DOI: 10.1038/s41598-017-16013-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 11/06/2017] [Indexed: 11/09/2022] Open
Abstract
Wood represents a promising source of sugars to produce bio-based renewables, including biofuels. However, breaking down lignocellulose requires costly pretreatments because lignocellulose is recalcitrant to enzymatic saccharification. Increasing saccharification potential would greatly contribute to make wood a competitive alternative to petroleum, but this requires improving wood properties. To identify wood biomass traits associated with saccharification, we analyzed a total of 65 traits related to wood chemistry, anatomy and structure, biomass production and saccharification in 40 genetically engineered Populus tree lines. These lines exhibited broad variation in quantitative traits, allowing for multivariate analyses and mathematical modeling. Modeling revealed that seven wood biomass traits associated in a predictive manner with saccharification of glucose after pretreatment. Four of these seven traits were also negatively associated with biomass production, suggesting a trade-off between saccharification potential and total biomass, which has previously been observed to offset the overall sugar yield from whole trees. We therefore estimated the "total-wood glucose yield" (TWG) from whole trees and found 22 biomass traits predictive of TWG after pretreatment. Both saccharification and TWG were associated with low abundant, often overlooked matrix polysaccharides such as arabinose and rhamnose which possibly represent new markers for improved Populus feedstocks.
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Affiliation(s)
- Sacha Escamez
- Department of Plant Physiology, Umeå University, Umeå Plant Science Centre (UPSC), SE-901 87, Umeå, Sweden.
| | | | - Marta Derba-Maceluch
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå Plant Science Centre (UPSC), SE-901 83, Umeå, Sweden
| | - Sven-Olof Lundqvist
- INNVENTIA AB, RISE Bioeconomy, Drottning Kristinas väg 61 B, SE-114 28, Stockholm, Sweden
| | - Ewa J Mellerowicz
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå Plant Science Centre (UPSC), SE-901 83, Umeå, Sweden
| | - Leif J Jönsson
- Department of Chemistry, Umeå University, SE-901 87, Umeå, Sweden
| | - Hannele Tuominen
- Department of Plant Physiology, Umeå University, Umeå Plant Science Centre (UPSC), SE-901 87, Umeå, Sweden.
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31
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MacDonald MJ, Cornejo NR, Gellman SH. Inhibition of Ice Recrystallization by Nylon-3 Polymers. ACS Macro Lett 2017; 6:695-699. [PMID: 35650872 DOI: 10.1021/acsmacrolett.7b00396] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nontoxic cryoprotectants are needed for storage of tissues and food preservation. Frozen tissue is particularly susceptible to damage caused by formation of large ice crystals during the thawing process. The current practice of using 5 wt % DMSO for cryopreservation does not produce 100% cell viability post-thaw, at least in part because of DMSO toxicity that is manifested during the freezing and thawing stages of the process. Recently, poly(vinyl alcohol) (PVA) has shown promise in inhibiting ice recrystallization, an activity that is critical for cryoprotection. Inspired by this discovery, we have evaluated nylon-3 polymers for ice recrystallization inhibition activity and for toxicity toward mammalian cells. A survey of homo- and heteropolymers, with side chains bearing variable functionality, has identified new nylon-3 materials that display excellent ice recrystallization inhibition activity and low toxicity.
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Affiliation(s)
- Melissa J. MacDonald
- Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - Natasha R. Cornejo
- Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - Samuel H. Gellman
- Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
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32
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Venturas MD, Sperry JS, Hacke UG. Plant xylem hydraulics: What we understand, current research, and future challenges. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2017; 59:356-389. [PMID: 28296168 DOI: 10.1111/jipb.12534] [Citation(s) in RCA: 159] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 03/09/2017] [Indexed: 05/22/2023]
Abstract
Herein we review the current state-of-the-art of plant hydraulics in the context of plant physiology, ecology, and evolution, focusing on current and future research opportunities. We explain the physics of water transport in plants and the limits of this transport system, highlighting the relationships between xylem structure and function. We describe the great variety of techniques existing for evaluating xylem resistance to cavitation. We address several methodological issues and their connection with current debates on conduit refilling and exponentially shaped vulnerability curves. We analyze the trade-offs existing between water transport safety and efficiency. We also stress how little information is available on molecular biology of cavitation and the potential role of aquaporins in conduit refilling. Finally, we draw attention to how plant hydraulic traits can be used for modeling stomatal responses to environmental variables and climate change, including drought mortality.
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Affiliation(s)
- Martin D Venturas
- Department of Biology, University of Utah, 257 S 1400E, Salt Lake City, UT, 84112, USA
| | - John S Sperry
- Department of Biology, University of Utah, 257 S 1400E, Salt Lake City, UT, 84112, USA
| | - Uwe G Hacke
- Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2E3, Canada
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33
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Buhl C, Meilan R, Lindroth RL. Genetic Modification of Lignin in Hybrid Poplar (Populus alba × Populus tremula) Does Not Substantially Alter Plant Defense or Arthropod Communities. JOURNAL OF INSECT SCIENCE (ONLINE) 2017; 17:3858857. [PMID: 28973575 PMCID: PMC5538326 DOI: 10.1093/jisesa/iex052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Indexed: 06/07/2023]
Abstract
Lignin impedes access to cellulose during biofuel production and pulping but trees can be genetically modified to improve processing efficiency. Modification of lignin may have nontarget effects on mechanical and chemical resistance and subsequent arthropod community responses with respect to pest susceptibility and arthropod biodiversity. We quantified foliar mechanical and chemical resistance traits in lignin-modified and wild-type (WT) poplar (Populus alba × Populus tremula) grown in a plantation and censused arthropods present on these trees to determine total abundance, as well as species richness, diversity and community composition. Our results indicate that mechanical resistance was not affected by lignin modification and only one genetic construct resulted in a (modest) change in chemical resistance. Arthropod abundance and community composition were consistent across modified and WT trees, but transgenics produced using one construct exhibited higher species richness and diversity relative to the WT. Our findings indicate that modification of lignin in poplar does not negatively affect herbivore resistance traits or arthropod community response, and may even result in a source of increased genetic diversity in trees and arthropod communities.
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Affiliation(s)
- Christine Buhl
- Department of Entomology, University of Wisconsin-Madison, 1630 Linden Dr., Madison, WI 53706 (; )
- Current address: 2600 State St., Salem, OR 97310
| | - Richard Meilan
- Department of Forestry and Natural Resources, Purdue University, 715 W. State St., West Lafayette, IN 47907 ()
| | - Richard L. Lindroth
- Department of Entomology, University of Wisconsin-Madison, 1630 Linden Dr., Madison, WI 53706 (; )
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Leśniewska J, Öhman D, Krzesłowska M, Kushwah S, Barciszewska-Pacak M, Kleczkowski LA, Sundberg B, Moritz T, Mellerowicz EJ. Defense Responses in Aspen with Altered Pectin Methylesterase Activity Reveal the Hormonal Inducers of Tyloses. PLANT PHYSIOLOGY 2017; 173:1409-1419. [PMID: 27923986 PMCID: PMC5291032 DOI: 10.1104/pp.16.01443] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 12/02/2016] [Indexed: 05/19/2023]
Abstract
Tyloses are ingrowths of parenchyma cells into the lumen of embolized xylem vessels, thereby protecting the remaining xylem from pathogens. They are found in heartwood, sapwood, and in abscission zones and can be induced by various stresses, but their molecular triggers are unknown. Here, we report that down-regulation of PECTIN METHYLESTERASE1 (PtxtPME1) in aspen (Populus tremula × tremuloides) triggers the formation of tyloses and activation of oxidative stress. We tested whether any of the oxidative stress-related hormones could induce tyloses in intact plantlets grown in sterile culture. Jasmonates, including jasmonic acid (JA) and methyl jasmonate, induced the formation of tyloses, whereas treatments with salicylic acid (SA) and 1-aminocyclopropane-1-carboxylic acid (ACC) were ineffective. SA abolished the induction of tyloses by JA, whereas ACC was synergistic with JA. The ability of ACC to stimulate tyloses formation when combined with JA depended on ethylene (ET) signaling, as shown by a decrease in the response in ET-insensitive plants. Measurements of internal ACC and JA concentrations in wild-type and ET-insensitive plants treated simultaneously with these two compounds indicated that ACC and JA regulate each other's concentration in an ET-dependent manner. The findings indicate that jasmonates acting synergistically with ethylene are the key molecular triggers of tyloses.
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Affiliation(s)
- Joanna Leśniewska
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Center, Swedish University of Agricultural Sciences, S901-83 Umeå, Sweden (J.L., D.Ö., M.K., S.K., M.B.-P., B.S., T.M., E.J.M.); and Department of Plant Physiology, Umeå Plant Science Center, Umeå University, S901-87 Umeå, Sweden (L.A.K.)
| | - David Öhman
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Center, Swedish University of Agricultural Sciences, S901-83 Umeå, Sweden (J.L., D.Ö., M.K., S.K., M.B.-P., B.S., T.M., E.J.M.); and Department of Plant Physiology, Umeå Plant Science Center, Umeå University, S901-87 Umeå, Sweden (L.A.K.)
| | - Magdalena Krzesłowska
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Center, Swedish University of Agricultural Sciences, S901-83 Umeå, Sweden (J.L., D.Ö., M.K., S.K., M.B.-P., B.S., T.M., E.J.M.); and Department of Plant Physiology, Umeå Plant Science Center, Umeå University, S901-87 Umeå, Sweden (L.A.K.)
| | - Sunita Kushwah
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Center, Swedish University of Agricultural Sciences, S901-83 Umeå, Sweden (J.L., D.Ö., M.K., S.K., M.B.-P., B.S., T.M., E.J.M.); and Department of Plant Physiology, Umeå Plant Science Center, Umeå University, S901-87 Umeå, Sweden (L.A.K.)
| | - Maria Barciszewska-Pacak
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Center, Swedish University of Agricultural Sciences, S901-83 Umeå, Sweden (J.L., D.Ö., M.K., S.K., M.B.-P., B.S., T.M., E.J.M.); and Department of Plant Physiology, Umeå Plant Science Center, Umeå University, S901-87 Umeå, Sweden (L.A.K.)
| | - Leszek A Kleczkowski
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Center, Swedish University of Agricultural Sciences, S901-83 Umeå, Sweden (J.L., D.Ö., M.K., S.K., M.B.-P., B.S., T.M., E.J.M.); and Department of Plant Physiology, Umeå Plant Science Center, Umeå University, S901-87 Umeå, Sweden (L.A.K.)
| | - Björn Sundberg
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Center, Swedish University of Agricultural Sciences, S901-83 Umeå, Sweden (J.L., D.Ö., M.K., S.K., M.B.-P., B.S., T.M., E.J.M.); and Department of Plant Physiology, Umeå Plant Science Center, Umeå University, S901-87 Umeå, Sweden (L.A.K.)
| | - Thomas Moritz
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Center, Swedish University of Agricultural Sciences, S901-83 Umeå, Sweden (J.L., D.Ö., M.K., S.K., M.B.-P., B.S., T.M., E.J.M.); and Department of Plant Physiology, Umeå Plant Science Center, Umeå University, S901-87 Umeå, Sweden (L.A.K.)
| | - Ewa J Mellerowicz
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Center, Swedish University of Agricultural Sciences, S901-83 Umeå, Sweden (J.L., D.Ö., M.K., S.K., M.B.-P., B.S., T.M., E.J.M.); and Department of Plant Physiology, Umeå Plant Science Center, Umeå University, S901-87 Umeå, Sweden (L.A.K.)
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Macaya-Sanz D, Chen J, Kalluri UC, Muchero W, Tschaplinski TJ, Gunter LE, Simon SJ, Biswal AK, Bryan AC, Payyavula R, Xie M, Yang Y, Zhang J, Mohnen D, Tuskan GA, DiFazio SP. Agronomic performance of Populus deltoides trees engineered for biofuel production. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:253. [PMID: 29213313 PMCID: PMC5707814 DOI: 10.1186/s13068-017-0934-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 10/19/2017] [Indexed: 05/02/2023]
Abstract
BACKGROUND One of the major barriers to the development of lignocellulosic feedstocks is the recalcitrance of plant cell walls to deconstruction and saccharification. Recalcitrance can be reduced by targeting genes involved in cell wall biosynthesis, but this can have unintended consequences that compromise the agronomic performance of the trees under field conditions. Here we report the results of a field trial of fourteen distinct transgenic Populus deltoides lines that had previously demonstrated reduced recalcitrance without yield penalties under greenhouse conditions. RESULTS Survival and productivity of the trial were excellent in the first year, and there was little evidence for reduced performance of the transgenic lines with modified target gene expression. Surprisingly, the most striking phenotypic effects in this trial were for two empty-vector control lines that had modified bud set and bud flush. This is most likely due to somaclonal variation or insertional mutagenesis. Traits related to yield, crown architecture, herbivory, pathogen response, and frost damage showed few significant differences between target gene transgenics and empty vector controls. However, there were a few interesting exceptions. Lines overexpressing the DUF231 gene, a putative O-acetyltransferase, showed early bud flush and marginally increased height growth. Lines overexpressing the DUF266 gene, a putative glycosyltransferase, had significantly decreased stem internode length and slightly higher volume index. Finally, lines overexpressing the PFD2 gene, a putative member of the prefoldin complex, had a slightly reduced volume index. CONCLUSIONS This field trial demonstrates that these cell wall modifications, which decreased cell wall recalcitrance under laboratory conditions, did not seriously compromise first-year performance in the field, despite substantial challenges, including an outbreak of a stem boring insect (Gypsonoma haimbachiana), attack by a leaf rust pathogen (Melampsora spp.), and a late frost event. This bodes well for the potential utility of these lines as advanced biofuels feedstocks.
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Affiliation(s)
- David Macaya-Sanz
- Department of Biology, West Virginia University, Morgantown, WV 26506 USA
| | - Jin‐Gui Chen
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Udaya C. Kalluri
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Wellington Muchero
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Timothy J. Tschaplinski
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Lee E. Gunter
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Sandra J. Simon
- Department of Biology, West Virginia University, Morgantown, WV 26506 USA
| | - Ajaya K. Biswal
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602 USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602 USA
| | - Anthony C. Bryan
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Raja Payyavula
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Meng Xie
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Yongil Yang
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Jin Zhang
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Debra Mohnen
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602 USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602 USA
| | - Gerald A. Tuskan
- BioEnergy Science Center and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Stephen P. DiFazio
- Department of Biology, West Virginia University, Morgantown, WV 26506 USA
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Park J, Kim HK, Ryu J, Ahn S, Lee SJ, Hwang I. Functional water flow pathways and hydraulic regulation in the xylem network of Arabidopsis. PLANT & CELL PHYSIOLOGY 2015; 56:520-531. [PMID: 25520406 DOI: 10.1093/pcp/pcu198] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In vascular plants, the xylem network constitutes a complex microfluidic system. The relationship between vascular network architecture and functional hydraulic regulation during actual water flow remains unexplored. Here, we developed a method to visualize individual xylem vessels of the 3D xylem network of Arabidopsis thaliana, and to analyze the functional activities of these vessels using synchrotron X-ray computed tomography with hydrophilic gold nanoparticles as flow tracers. We show how the organization of the xylem network changes dynamically throughout the plant, and reveal how the elementary units of this transport system are organized to ensure both long-distance axial water transport and local lateral water transport. Xylem vessels form distinct clusters that operate as functional units, and the activity of these units, which determines water flow pathways, is modulated not only by varying the number and size of xylem vessels, but also by altering their interconnectivity and spatial arrangement. Based on these findings, we propose a regulatory model of water transport that ensures hydraulic efficiency and safety.
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Affiliation(s)
- Joonghyuk Park
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea These authors contributed equally to this work
| | - Hae Koo Kim
- Center for Biofluid and Biomimic Research, Pohang University of Science and Technology, Pohang 790-784, Korea Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang 790-784, Korea These authors contributed equally to this work. Present address: Global Conservation Agriculture Program, International Maize and Wheat Improvement Center (CIMMYT), P.O. Box 5689, Addis Ababa, Ethiopia
| | - Jeongeun Ryu
- Center for Biofluid and Biomimic Research, Pohang University of Science and Technology, Pohang 790-784, Korea Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Sungsook Ahn
- Center for Biofluid and Biomimic Research, Pohang University of Science and Technology, Pohang 790-784, Korea Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Sang Joon Lee
- Center for Biofluid and Biomimic Research, Pohang University of Science and Technology, Pohang 790-784, Korea Department of Mechanical Engineering, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Ildoo Hwang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 790-784, Korea
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37
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Porth I, El-Kassaby YA. Using Populus as a lignocellulosic feedstock for bioethanol. Biotechnol J 2015; 10:510-24. [PMID: 25676392 DOI: 10.1002/biot.201400194] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 11/11/2014] [Accepted: 12/30/2014] [Indexed: 11/10/2022]
Abstract
Populus species along with species from the sister genus Salix will provide valuable feedstock resources for advanced second-generation biofuels. Their inherent fast growth characteristics can particularly be exploited for short rotation management, a time and energy saving cultivation alternative for lignocellulosic feedstock supply. Salicaceae possess inherent cell wall characteristics with favorable cellulose to lignin ratios for utilization as bioethanol crop. We review economically important traits relevant for intensively managed biofuel crop plantations, genomic and phenotypic resources available for Populus, breeding strategies for forest trees dedicated to bioenergy provision, and bioprocesses and downstream applications related to opportunities using Salicaceae as a renewable resource. Challenges need to be resolved for every single step of the conversion process chain, i.e., starting from tree domestication for improved performance as a bioenergy crop, bioconversion process, policy development for land use changes associated with advanced biofuels, and harvest and supply logistics associated with industrial-scale biorefinery plants using Populus as feedstock. Significant hurdles towards cost and energy efficiency, environmental friendliness, and yield maximization with regards to biomass pretreatment, saccharification, and fermentation of celluloses and the sustainability of biorefineries as a whole still need to be overcome.
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Affiliation(s)
- Ilga Porth
- Forest and Conservation Sciences, University of British Columbia, Vancouver, Canada.
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38
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Ménard D, Pesquet E. Cellular interactions during tracheary elements formation and function. CURRENT OPINION IN PLANT BIOLOGY 2015; 23:109-15. [PMID: 25545993 DOI: 10.1016/j.pbi.2014.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 11/17/2014] [Accepted: 12/11/2014] [Indexed: 05/08/2023]
Abstract
The survival of higher plant species on land depends on the development and function of an efficient vascular system distributing water and minerals absorbed by roots to all aerial organs. This conduction and distribution of plant sap relies on specialized cells named tracheary elements (TEs). In contrast to many other cell types in plants, TEs are functionalized by cell death that hollows the cell protoplast to make way for the sap. To maintain a stable conducting function during plant development, recovery from vascular damages as well as to adapt to environmental changes, TEs are completely dependent on direct cellular interactions with neighboring xylem parenchyma cells (XPs).
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Affiliation(s)
- Delphine Ménard
- Umeå Plant Science Centre (UPSC), Department of Plant Physiology, Umeå University, S-901 87 Umeå, Sweden
| | - Edouard Pesquet
- Umeå Plant Science Centre (UPSC), Department of Plant Physiology, Umeå University, S-901 87 Umeå, Sweden.
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39
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Ratke C, Pawar PMA, Balasubramanian VK, Naumann M, Duncranz ML, Derba-Maceluch M, Gorzsás A, Endo S, Ezcurra I, Mellerowicz EJ. Populus GT43 family members group into distinct sets required for primary and secondary wall xylan biosynthesis and include useful promoters for wood modification. PLANT BIOTECHNOLOGY JOURNAL 2015; 13:26-37. [PMID: 25100045 DOI: 10.1111/pbi.12232] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 06/24/2014] [Accepted: 06/29/2014] [Indexed: 05/05/2023]
Abstract
The plant GT43 protein family includes xylosyltransferases that are known to be required for xylan backbone biosynthesis, but have incompletely understood specificities. RT-qPCR and histochemical (GUS) analyses of expression patterns of GT43 members in hybrid aspen, reported here, revealed that three clades of the family have markedly differing specificity towards secondary wall-forming cells (wood and extraxylary fibres). Intriguingly, GT43A and B genes (corresponding to the Arabidopsis IRX9 clade) showed higher specificity for secondary-walled cells than GT43C and D genes (IRX14 clade), although both IRX9 and IRX14 are required for xylosyltransferase activity. The remaining genes, GT43E, F and G (IRX9-L clade), showed broad expression patterns. Transient transactivation analyses of GT43A and B reporters demonstrated that they are activated by PtxtMYB021 and PNAC085 (master secondary wall switches), mediated in PtxtMYB021 activation by an AC element. The high observed secondary cell wall specificity of GT43B expression prompted tests of the efficiency of its promoter (pGT43B), relative to the CaMV 35S (35S) promoter, for overexpressing a xylan acetyl esterase (CE5) or downregulating REDUCED WALL ACETYLATION (RWA) family genes and thus engineering wood acetylation. CE5 expression was weaker when driven by pGT43B, but it reduced wood acetyl content substantially more efficiently than the 35S promoter. RNAi silencing of the RWA family, which was ineffective using 35S, was achieved when using GT43B promoter. These results show the utility of the GT43B promoter for genetically engineering properties of wood and fibres.
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Affiliation(s)
- Christine Ratke
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences (SLU), Umeå, Sweden
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40
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Sutela S, Hahl T, Tiimonen H, Aronen T, Ylioja T, Laakso T, Saranpää P, Chiang V, Julkunen-Tiitto R, Häggman H. Phenolic compounds and expression of 4CL genes in silver birch clones and Pt4CL1a lines. PLoS One 2014; 9:e114434. [PMID: 25502441 PMCID: PMC4263613 DOI: 10.1371/journal.pone.0114434] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 11/10/2014] [Indexed: 01/09/2023] Open
Abstract
A small multigene family encodes 4-coumarate:CoA ligases (4CLs) catalyzing the CoA ligation of hydroxycinnamic acids, a branch point step directing metabolites to a flavonoid or monolignol pathway. In the present study, we examined the effect of antisense Populus tremuloides 4CL (Pt4CL1) to the lignin and soluble phenolic compound composition of silver birch (Betula pendula) Pt4CL1a lines in comparison with non-transgenic silver birch clones. The endogenous expression of silver birch 4CL genes was recorded in the stems and leaves and also in leaves that were mechanically injured. In one of the transgenic Pt4CL1a lines, the ratio of syringyl (S) and guaiacyl (G) lignin units was increased. Moreover, the transcript levels of putative silver birch 4CL gene (Bp4CL1) were reduced and contents of cinnamic acid derivatives altered. In the other two Pt4CL1a lines changes were detected in the level of individual phenolic compounds. However, considerable variation was found in the transcript levels of silver birch 4CLs as well as in the concentration of phenolic compounds among the transgenic lines and non-transgenic clones. Wounding induced the expression of Bp4CL1 and Bp4CL2 in leaves in all clones and transgenic lines, whereas the transcript levels of Bp4CL3 and Bp4CL4 remained unchanged. Moreover, minor changes were detected in the concentrations of phenolic compounds caused by wounding. As an overall trend the wounding decreased the flavonoid content in silver birches and increased the content of soluble condensed tannins. The results indicate that by reducing the Bp4CL1 transcript levels lignin composition could be modified. However, the alterations found among the Pt4CL1a lines and the non-transgenic clones were within the natural variation of silver birches, as shown in the present study by the clonal differences in the transcripts levels of 4CL genes, soluble phenolic compounds and condensed tannins.
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Affiliation(s)
- Suvi Sutela
- Department of Biology, University of Oulu, Oulu, Finland
| | - Terhi Hahl
- Department of Biology, University of Oulu, Oulu, Finland
| | - Heidi Tiimonen
- The Finnish Border Guard, Border and Coast Guard Academy, Imatra, Finland
| | - Tuija Aronen
- Finnish Forest Research Institute, Eastern Finland Regional Unit (Punkaharju Unit), Punkaharju, Finland
| | - Tiina Ylioja
- Finnish Forest Research Institute, Southern Finland Regional Unit (Vantaa Unit), Vantaa, Finland
| | - Tapio Laakso
- Finnish Forest Research Institute, Southern Finland Regional Unit (Vantaa Unit), Vantaa, Finland
| | - Pekka Saranpää
- Finnish Forest Research Institute, Southern Finland Regional Unit (Vantaa Unit), Vantaa, Finland
| | - Vincent Chiang
- Forest Biotechnology Group, Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, North Carolina, United States of America
| | | | - Hely Häggman
- Department of Biology, University of Oulu, Oulu, Finland
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41
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Wang JP, Naik PP, Chen HC, Shi R, Lin CY, Liu J, Shuford CM, Li Q, Sun YH, Tunlaya-Anukit S, Williams CM, Muddiman DC, Ducoste JJ, Sederoff RR, Chiang VL. Complete proteomic-based enzyme reaction and inhibition kinetics reveal how monolignol biosynthetic enzyme families affect metabolic flux and lignin in Populus trichocarpa. THE PLANT CELL 2014; 26:894-914. [PMID: 24619611 PMCID: PMC4001400 DOI: 10.1105/tpc.113.120881] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 01/12/2014] [Accepted: 02/12/2014] [Indexed: 05/17/2023]
Abstract
We established a predictive kinetic metabolic-flux model for the 21 enzymes and 24 metabolites of the monolignol biosynthetic pathway using Populus trichocarpa secondary differentiating xylem. To establish this model, a comprehensive study was performed to obtain the reaction and inhibition kinetic parameters of all 21 enzymes based on functional recombinant proteins. A total of 104 Michaelis-Menten kinetic parameters and 85 inhibition kinetic parameters were derived from these enzymes. Through mass spectrometry, we obtained the absolute quantities of all 21 pathway enzymes in the secondary differentiating xylem. This extensive experimental data set, generated from a single tissue specialized in wood formation, was used to construct the predictive kinetic metabolic-flux model to provide a comprehensive mathematical description of the monolignol biosynthetic pathway. The model was validated using experimental data from transgenic P. trichocarpa plants. The model predicts how pathway enzymes affect lignin content and composition, explains a long-standing paradox regarding the regulation of monolignol subunit ratios in lignin, and reveals novel mechanisms involved in the regulation of lignin biosynthesis. This model provides an explanation of the effects of genetic and transgenic perturbations of the monolignol biosynthetic pathway in flowering plants.
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Affiliation(s)
- Jack P. Wang
- 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, North Carolina
27695
| | - Punith P. Naik
- Civil, Construction, and Environmental Engineering, North
Carolina State University, Raleigh, North Carolina 27695
| | - Hsi-Chuan Chen
- Forest Biotechnology Group, Department of Forestry and
Environmental Resources, North Carolina State University, Raleigh, North Carolina
27695
| | - Rui Shi
- Forest Biotechnology Group, Department of Forestry and
Environmental Resources, North Carolina State University, Raleigh, North Carolina
27695
| | - Chien-Yuan Lin
- Forest Biotechnology Group, Department of Forestry and
Environmental Resources, North Carolina State University, Raleigh, North Carolina
27695
| | - Jie Liu
- Forest Biotechnology Group, Department of Forestry and
Environmental Resources, North Carolina State University, Raleigh, North Carolina
27695
| | - Christopher M. Shuford
- Forest Biotechnology Group, Department of Forestry and
Environmental Resources, North Carolina State University, Raleigh, North Carolina
27695
| | - Quanzi Li
- 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, North Carolina
27695
- College of Forestry, Shandong Agricultural University,
Taian, Shandong 271018, China
| | - Ying-Hsuan Sun
- Department of Forestry, National Chung-Hsing University,
Taichung, 40227, Taiwan
| | - Sermsawat Tunlaya-Anukit
- Forest Biotechnology Group, Department of Forestry and
Environmental Resources, North Carolina State University, Raleigh, North Carolina
27695
| | - Cranos M. Williams
- Electrical and Computer Engineering, North Carolina State
University, Raleigh, North Carolina 27695
| | - David C. Muddiman
- W.M. Keck FT-ICR Mass Spectrometry Laboratory, Department
of Chemistry, North Carolina State University, Raleigh, North Carolina 27695
| | - Joel J. Ducoste
- Civil, Construction, and Environmental Engineering, North
Carolina State University, Raleigh, North Carolina 27695
| | - Ronald R. Sederoff
- Forest Biotechnology Group, Department of Forestry and
Environmental Resources, North Carolina State University, Raleigh, North Carolina
27695
| | - 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, North Carolina
27695
- Department of Forest Biomaterials, North Carolina State
University, Raleigh, North Carolina 27695
- Address correspondence to
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42
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Littlewood J, Guo M, Boerjan W, Murphy RJ. Bioethanol from poplar: a commercially viable alternative to fossil fuel in the European Union. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:113. [PMID: 25788978 PMCID: PMC4364105 DOI: 10.1186/1754-6834-7-113] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Accepted: 07/09/2014] [Indexed: 05/02/2023]
Abstract
BACKGROUND The European Union has made it a strategic objective to develop its biofuels market in order to minimize greenhouse gas (GHG) emissions, to help mitigate climate change and to address energy insecurity within the transport sector. Despite targets set at national and supranational levels, lignocellulosic bioethanol production has yet to be widely commercialized in the European Union. Here, we use techno-economic modeling to compare the price of bioethanol produced from short rotation coppice (SRC) poplar feedstocks under two leading processing technologies in five European countries. RESULTS Our evaluation shows that the type of processing technology and varying national costs between countries results in a wide range of bioethanol production prices (€0.275 to 0.727/l). The lowest production prices for bioethanol were found in countries that had cheap feedstock costs and high prices for renewable electricity. Taxes and other costs had a significant influence on fuel prices at the petrol station, and therefore the presence and amount of government support for bioethanol was a major factor determining the competitiveness of bioethanol with conventional fuel. In a forward-looking scenario, genetically engineering poplar with a reduced lignin content showed potential to enhance the competitiveness of bioethanol with conventional fuel by reducing overall costs by approximately 41% in four out of the five countries modeled. However, the possible wider phenotypic traits of advanced poplars needs to be fully investigated to ensure that these do not unintentionally negate the cost savings indicated. CONCLUSIONS Through these evaluations, we highlight the key bottlenecks within the bioethanol supply chain from the standpoint of various stakeholders. For producers, technologies that are best suited to the specific feedstock composition and national policies should be optimized. For policymakers, support schemes that benefit emerging bioethanol producers and allow renewable fuel to be economically competitive with petrol should be established. Finally, for researchers, better control over plant genetic engineering and advanced breeding and its consequential economic impact would bring valuable contributions towards developing an economically sustainable bioethanol market within the European Union.
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Affiliation(s)
- Jade Littlewood
- />Department of Life Sciences, Imperial College London, London, SW7 2AZ UK
| | - Miao Guo
- />Department of Life Sciences, Imperial College London, London, SW7 2AZ UK
| | - Wout Boerjan
- />Department of Plant Systems Biology, VIB, Technologiepark 927, 9052 Gent, Belgium
- />Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052 Gent, Belgium
| | - Richard J Murphy
- />Centre for Environmental Strategy, Faculty of Engineering & Physical Sciences, University of Surrey, Guildford, Surrey, GU2 7XH UK
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Improved saccharification and ethanol yield from field-grown transgenic poplar deficient in cinnamoyl-CoA reductase. Proc Natl Acad Sci U S A 2013; 111:845-50. [PMID: 24379366 DOI: 10.1073/pnas.1321673111] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Lignin is one of the main factors determining recalcitrance to enzymatic processing of lignocellulosic biomass. Poplars (Populus tremula x Populus alba) down-regulated for cinnamoyl-CoA reductase (CCR), the enzyme catalyzing the first step in the monolignol-specific branch of the lignin biosynthetic pathway, were grown in field trials in Belgium and France under short-rotation coppice culture. Wood samples were classified according to the intensity of the red xylem coloration typically associated with CCR down-regulation. Saccharification assays under different pretreatment conditions (none, two alkaline, and one acid pretreatment) and simultaneous saccharification and fermentation assays showed that wood from the most affected transgenic trees had up to 161% increased ethanol yield. Fermentations of combined material from the complete set of 20-mo-old CCR-down-regulated trees, including bark and less efficiently down-regulated trees, still yielded ∼ 20% more ethanol on a weight basis. However, strong down-regulation of CCR also affected biomass yield. We conclude that CCR down-regulation may become a successful strategy to improve biomass processing if the variability in down-regulation and the yield penalty can be overcome.
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Porth I, Klápště J, Skyba O, Friedmann MC, Hannemann J, Ehlting J, El-Kassaby YA, Mansfield SD, Douglas CJ. Network analysis reveals the relationship among wood properties, gene expression levels and genotypes of natural Populus trichocarpa accessions. THE NEW PHYTOLOGIST 2013; 200:727-742. [PMID: 23889128 DOI: 10.1111/nph.12419] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 06/17/2013] [Indexed: 05/21/2023]
Abstract
High-throughput approaches have been widely applied to elucidate the genetic underpinnings of industrially important wood properties. Wood traits are polygenic in nature, but gene hierarchies can be assessed to identify the most important gene variants controlling specific traits within complex networks defining the overall wood phenotype. We tested a large set of genetic, genomic, and phenotypic information in an integrative approach to predict wood properties in Populus trichocarpa. Nine-yr-old natural P. trichocarpa trees including accessions with high contrasts in six traits related to wood chemistry and ultrastructure were profiled for gene expression on 49k Nimblegen (Roche NimbleGen Inc., Madison, WI, USA) array elements and for 28,831 polymorphic single nucleotide polymorphisms (SNPs). Pre-selected transcripts and SNPs with high statistical dependence on phenotypic traits were used in Bayesian network learning procedures with a stepwise K2 algorithm to infer phenotype-centric networks. Transcripts were pre-selected at a much lower logarithm of Bayes factor (logBF) threshold than SNPs and were not accommodated in the networks. Using persistent variables, we constructed cross-validated networks for variability in wood attributes, which contained four to six variables with 94-100% predictive accuracy. Accommodated gene variants revealed the hierarchy in the genetic architecture that underpins substantial phenotypic variability, and represent new tools to support the maximization of response to selection.
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Affiliation(s)
- Ilga Porth
- Department of Wood Science, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
- Department of Botany, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - Jaroslav Klápště
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
- Department of Dendrology and Forest Tree Breeding, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Prague, 165 21, Czech Republic
| | - Oleksandr Skyba
- Department of Wood Science, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - Michael C Friedmann
- Department of Botany, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - Jan Hannemann
- Department of Biology and Centre for Forest Biology, University of Victoria, Victoria, BC, Canada, V8W 3N5
| | - Juergen Ehlting
- Department of Biology and Centre for Forest Biology, University of Victoria, Victoria, BC, Canada, V8W 3N5
| | - Yousry A El-Kassaby
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - Shawn D Mansfield
- Department of Wood Science, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - Carl J Douglas
- Department of Botany, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
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Häggman H, Raybould A, Borem A, Fox T, Handley L, Hertzberg M, Lu MZ, Macdonald P, Oguchi T, Pasquali G, Pearson L, Peter G, Quemada H, Séguin A, Tattersall K, Ulian E, Walter C, McLean M. Genetically engineered trees for plantation forests: key considerations for environmental risk assessment. PLANT BIOTECHNOLOGY JOURNAL 2013; 11:785-98. [PMID: 23915092 PMCID: PMC3823068 DOI: 10.1111/pbi.12100] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 06/18/2013] [Accepted: 06/23/2013] [Indexed: 05/18/2023]
Abstract
Forests are vital to the world's ecological, social, cultural and economic well-being yet sustainable provision of goods and services from forests is increasingly challenged by pressures such as growing demand for wood and other forest products, land conversion and degradation, and climate change. Intensively managed, highly productive forestry incorporating the most advanced methods for tree breeding, including the application of genetic engineering (GE), has tremendous potential for producing more wood on less land. However, the deployment of GE trees in plantation forests is a controversial topic and concerns have been particularly expressed about potential harms to the environment. This paper, prepared by an international group of experts in silviculture, forest tree breeding, forest biotechnology and environmental risk assessment (ERA) that met in April 2012, examines how the ERA paradigm used for GE crop plants may be applied to GE trees for use in plantation forests. It emphasizes the importance of differentiating between ERA for confined field trials of GE trees, and ERA for unconfined or commercial-scale releases. In the case of the latter, particular attention is paid to characteristics of forest trees that distinguish them from shorter-lived plant species, the temporal and spatial scale of forests, and the biodiversity of the plantation forest as a receiving environment.
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Affiliation(s)
- Hely Häggman
- Department of Biology, University of OuluOulu, Finland
| | - Alan Raybould
- Syngenta Jealott's Hill International Research CentreBracknell, UK
| | - Aluizio Borem
- Departamento de Fitotecnia, Universidade Federal de ViçosaViçosa, Brazil
| | - Thomas Fox
- Department of Forest Resources and Environmental Conservation, Virginia Polytechnic Institute and State UniversityBlacksburg, VA, USA
| | - Levis Handley
- Biotechnology Regulatory Services, United States Department of AgricultureRiverdale, MD, USA
| | | | - Meng-Zu Lu
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of ForestryBeijing, China
| | - Philip Macdonald
- Plant and Biotechnology Risk Assessment, Canadian Food Inspection AgencyOttawa, ON, Canada
| | - Taichi Oguchi
- Gene Research Center, University of TsukubaTsukuba, Japan
| | - Giancarlo Pasquali
- Centro de Biotecnologia, Universidade Federal do Rio Grande do SulPorto Alegre, Brazil
| | | | - Gary Peter
- School of Forest Resources and Conservation, University of FloridaGainesville, FL, USA
| | | | | | | | | | | | - Morven McLean
- Center for Environmental Risk AssessmentWashington, DC, USA
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Ratnayake K, Joyce DC, Webb RI. Cu2+ inhibition of gel secretion in the xylem and its potential implications for water uptake of cut Acacia holosericea stems. PHYSIOLOGIA PLANTARUM 2013; 148:538-548. [PMID: 23368900 DOI: 10.1111/ppl.12028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 01/03/2013] [Accepted: 01/16/2013] [Indexed: 06/01/2023]
Abstract
Maintaining a high rate of water uptake is crucial for maximum longevity of cut stems. Physiological gel/tylosis formation decreases water transport efficiency in the xylem. The primary mechanism of action for post-harvest Cu(2+) treatments in improving cut flower and foliage longevity has been elusive. The effect of Cu(2+) on wound-induced xylem vessel occlusion was investigated for Acacia holosericea A. Cunn. ex G. Don. Experiments were conducted using a Cu(2+) pulse (5 h, 2.2 mM) and a Cu(2+) vase solution (0.5 mM) vs a deionized water (DIW) control. Development of xylem blockage in the stem-end region 10 mm proximal to the wounded stem surface was examined over 21 days by light and transmission electron microscopy. Xylem vessels of stems stood into DIW were occluded with gels secreted into vessel lumens via pits from surrounding axial parenchyma cells. Gel secretion was initiated within 1-2 days post-wounding and gels were detected in the xylem from day 3. In contrast, Cu(2+) treatments disrupted the surrounding parenchyma cells, thereby inhibiting gel secretion and maintaining the vessel lumens devoid of occlusions. The Cu(2+) treatments significantly improved water uptake by the cut stems as compared to the control.
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Affiliation(s)
- Kamani Ratnayake
- The University of Queensland, School of Agriculture and Food Sciences, Gatton, QLD, 4343, Australia.
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Brodersen CR, McElrone AJ. Maintenance of xylem Network Transport Capacity: A Review of Embolism Repair in Vascular Plants. FRONTIERS IN PLANT SCIENCE 2013; 4:108. [PMID: 23630539 PMCID: PMC3633935 DOI: 10.3389/fpls.2013.00108] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Accepted: 04/09/2013] [Indexed: 05/17/2023]
Abstract
Maintenance of long distance water transport in xylem is essential to plant health and productivity. Both biotic and abiotic environmental conditions lead to embolism formation within the xylem resulting in lost transport capacity and ultimately death. Plants exhibit a variety of strategies to either prevent or restore hydraulic capacity through cavitation resistance with specialized anatomy, replacement of compromised conduits with new growth, and a metabolically active embolism repair mechanism. In recent years, mounting evidence suggests that metabolically active cells surrounding the xylem conduits in some, but not all, species are capable of restoring hydraulic conductivity. This review summarizes our current understanding of the osmotically driven embolism repair mechanism, the known genetic and anatomical components related to embolism repair, rehydration pathways through the xylem, and the role of capacitance. Anatomical differences between functional plant groups may be one of the limiting factors that allow some plants to refill while others do not, but further investigations are necessary to fully understand this dynamic process. Finally, xylem networks should no longer be considered an assemblage of dead, empty conduits, but instead a metabolically active tissue finely tuned to respond to ever changing environmental cues.
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Affiliation(s)
- Craig R. Brodersen
- Horticultural Sciences Department, Citrus Research and Education Center, University of FloridaLake Alfred, FL, USA
| | - Andrew J. McElrone
- Crops Pathology and Genetics Research Unit, USDA-ARSDavis, CA, USA
- Department of Viticulture and Enology, University of California DavisDavis, CA, USA
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Yang F, Mitra P, Zhang L, Prak L, Verhertbruggen Y, Kim JS, Sun L, Zheng K, Tang K, Auer M, Scheller HV, Loqué D. Engineering secondary cell wall deposition in plants. PLANT BIOTECHNOLOGY JOURNAL 2013; 11:325-35. [PMID: 23140549 PMCID: PMC3644865 DOI: 10.1111/pbi.12016] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 09/21/2012] [Accepted: 09/25/2012] [Indexed: 05/17/2023]
Abstract
Lignocellulosic biomass was used for thousands of years as animal feed and is now considered a great sugar source for biofuels production. It is composed mostly of secondary cell walls built with polysaccharide polymers that are embedded in lignin to reinforce the cell wall structure and maintain its integrity. Lignin is the primary material responsible for biomass recalcitrance to enzymatic hydrolysis. During plant development, deep reductions of lignin cause growth defects and often correlate with the loss of vessel integrity that adversely affects water and nutrient transport in plants. The work presented here describes a new approach to decrease lignin content while preventing vessel collapse and introduces a new strategy to boost transcription factor expression in native tissues. We used synthetic biology tools in Arabidopsis to rewire the secondary cell network by changing promoter-coding sequence associations. The result was a reduction in lignin and an increase in polysaccharide depositions in fibre cells. The promoter of a key lignin gene, C4H, was replaced by the vessel-specific promoter of transcription factor VND6. This rewired lignin biosynthesis specifically for vessel formation while disconnecting C4H expression from the fibre regulatory network. Secondly, the promoter of the IRX8 gene, secondary cell wall glycosyltransferase, was used to express a new copy of the fibre transcription factor NST1, and as the IRX8 promoter is induced by NST1, this also created an artificial positive feedback loop (APFL). The combination of strategies-lignin rewiring with APFL insertion-enhances polysaccharide deposition in stems without over-lignifying them, resulting in higher sugar yields after enzymatic hydrolysis.
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Affiliation(s)
- Fan Yang
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National LaboratoryOne Cyclotron Road, Berkeley, CA, USA
| | - Prajakta Mitra
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National LaboratoryOne Cyclotron Road, Berkeley, CA, USA
| | - Ling Zhang
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National LaboratoryOne Cyclotron Road, Berkeley, CA, USA
- FSN Plant Biotechnology R&D Centre, Shanghai Jiaotong UniversityShanghai, China
| | - Lina Prak
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National LaboratoryOne Cyclotron Road, Berkeley, CA, USA
| | - Yves Verhertbruggen
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National LaboratoryOne Cyclotron Road, Berkeley, CA, USA
| | - Jin-Sun Kim
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National LaboratoryOne Cyclotron Road, Berkeley, CA, USA
| | - Lan Sun
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National LaboratoryOne Cyclotron Road, Berkeley, CA, USA
| | - Kejian Zheng
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National LaboratoryOne Cyclotron Road, Berkeley, CA, USA
| | - Kexuan Tang
- FSN Plant Biotechnology R&D Centre, Shanghai Jiaotong UniversityShanghai, China
| | - Manfred Auer
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National LaboratoryOne Cyclotron Road, Berkeley, CA, USA
| | - Henrik V Scheller
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National LaboratoryOne Cyclotron Road, Berkeley, CA, USA
| | - Dominique Loqué
- Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National LaboratoryOne Cyclotron Road, Berkeley, CA, USA
- *Correspondence (fax 510 486 4252; email )
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Barnard DM, Lachenbruch B, McCulloh KA, Kitin P, Meinzer FC. Do ray cells provide a pathway for radial water movement in the stems of conifer trees? AMERICAN JOURNAL OF BOTANY 2013; 100:322-31. [PMID: 23347974 DOI: 10.3732/ajb.1200333] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
PREMISE OF THE STUDY The pathway of radial water movement in tree stems presents an unknown with respect to whole-tree hydraulics. Radial profiles have shown substantial axial sap flow in deeper layers of sapwood (that may lack direct connection to transpiring leaves), which suggests the existence of a radial pathway for water movement. Rays in tree stems include ray tracheids and/or ray parenchyma cells and may offer such a pathway for radial water transport. This study investigated relationships between radial hydraulic conductivity (k(s-rad)) and ray anatomical and stem morphological characteristics in the stems of three conifer species whose distributions span a natural aridity gradient across the Cascade Mountain range in Oregon, United States. METHODS The k(s-rad) was measured with a high-pressure flow meter. Ray tracheid and ray parenchyma characteristics and water transport properties were visualized using autofluorescence or confocal microscopy. KEY RESULTS The k(s-rad) did not vary predictably with sapwood depth among species and populations. Dye tracer did not infiltrate ray tracheids, and infiltration into ray parenchyma was limited. Regression analyses revealed inconsistent relationships between k(s-rad) and selected anatomical or growth characteristics when ecotypes were analyzed individually and weak relationships between k(s-rad) and these characteristics when data were pooled by tree species. CONCLUSIONS The lack of significant relationships between k(s-rad) and the ray and stem morphologies we studied, combined with the absence of dye tracer in ray tracheid and limited movement of dye into ray parenchyma suggests that rays may not facilitate radial water transport in the three conifer species studied.
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Affiliation(s)
- David M Barnard
- Department of Forest Ecosystems and Society, Oregon State University Corvallis, OR 97331 USA.
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Livingston DP, Henson CA, Tuong TD, Wise ML, Tallury SP, Duke SH. Histological analysis and 3D reconstruction of winter cereal crowns recovering from freezing: a unique response in oat (Avena sativa L.). PLoS One 2013; 8:e53468. [PMID: 23341944 PMCID: PMC3544926 DOI: 10.1371/journal.pone.0053468] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 11/30/2012] [Indexed: 11/30/2022] Open
Abstract
The crown is the below ground portion of the stem of a grass which contains meristematic cells that give rise to new shoots and roots following winter. To better understand mechanisms of survival from freezing, a histological analysis was performed on rye, wheat, barley and oat plants that had been frozen, thawed and allowed to resume growth under controlled conditions. Extensive tissue disruption and abnormal cell structure was noticed in the center of the crown of all 4 species with relatively normal cells on the outside edge of the crown. A unique visual response was found in oat in the shape of a ring of cells that stained red with Safranin. A tetrazolium analysis indicated that tissues immediately inside this ring were dead and those outside were alive. Fluorescence microscopy revealed that the barrier fluoresced with excitation between 405 and 445 nm. Three dimensional reconstruction of a cross sectional series of images indicated that the red staining cells took on a somewhat spherical shape with regions of no staining where roots entered the crown. Characterizing changes in plants recovering from freezing will help determine the genetic basis for mechanisms involved in this important aspect of winter hardiness.
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Affiliation(s)
- David P Livingston
- United States Department of Agriculture-Agricultural Research Service, Raleigh, NC, USA.
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