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Zhang L, Zhou Y, Zhang B. Xylan-directed cell wall assembly in grasses. PLANT PHYSIOLOGY 2024; 194:2197-2207. [PMID: 38095432 DOI: 10.1093/plphys/kiad665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 12/05/2023] [Indexed: 04/02/2024]
Abstract
Xylan is the most abundant hemicellulosic polysaccharide in the cell walls of grasses and is pivotal for the assembly of distinct cell wall structures that govern various cellular functions. Xylan also plays a crucial role in regulating biomass recalcitrance, ultimately affecting the utilization potential of lignocellulosic materials. Over the past decades, our understanding of the xylan biosynthetic machinery and cell wall organization has substantially improved due to the innovative application of multiple state-of-the-art techniques. Notably, novel xylan-based nanostructures have been revealed in the cell walls of xylem vessels, promoting a more extensive exploration of the role of xylan in the formation of cell wall structures. This Update summarizes recent achievements in understanding xylan biosynthesis, modification, modeling, and compartmentalization in grasses, providing a brief overview of cell wall assembly regarding xylan. We also discuss the potential for tailoring xylan to facilitate the breeding of elite energy and feed crops.
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Affiliation(s)
- Lanjun Zhang
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yihua Zhou
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- College of Advanced Agricultural Sciences, College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Baocai Zhang
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- College of Advanced Agricultural Sciences, College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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Lam LPY, Tobimatsu Y, Suzuki S, Tanaka T, Yamamoto S, Takeda-Kimura Y, Osakabe Y, Osakabe K, Ralph J, Bartley LE, Umezawa T. Disruption of p-coumaroyl-CoA:monolignol transferases in rice drastically alters lignin composition. PLANT PHYSIOLOGY 2024; 194:832-848. [PMID: 37831082 DOI: 10.1093/plphys/kiad549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 09/28/2023] [Accepted: 09/28/2023] [Indexed: 10/14/2023]
Abstract
Grasses are abundant feedstocks that can supply lignocellulosic biomass for production of cell-wall-derived chemicals. In grass cell walls, lignin is acylated with p-coumarate. These p-coumarate decorations arise from the incorporation of monolignol p-coumarate conjugates during lignification. A previous biochemical study identified a rice (Oryza sativa) BAHD acyltransferase (AT) with p-coumaroyl-CoA:monolignol transferase (PMT) activity in vitro. In this study, we determined that that enzyme, which we name OsPMT1 (also known as OsAT4), and the closely related OsPMT2 (OsAT3) harbor similar catalytic activity toward monolignols. We generated rice mutants deficient in either or both OsPMT1 and OsPMT2 by CRISPR/Cas9-mediated mutagenesis and subjected the mutants' cell walls to analysis using chemical and nuclear magnetic resonance methods. Our results demonstrated that OsPMT1 and OsPMT2 both function in lignin p-coumaroylation in the major vegetative tissues of rice. Notably, lignin-bound p-coumarate units were undetectable in the ospmt1 ospmt2-2 double-knockout mutant. Further, in-depth structural analysis of purified lignins from the ospmt1 ospmt2-2 mutant compared with control lignins from wild-type rice revealed stark changes in polymer structures, including alterations in syringyl/guaiacyl aromatic unit ratios and inter-monomeric linkage patterns, and increased molecular weights. Our results provide insights into lignin polymerization in grasses that will be useful for the optimization of bioengineering approaches for the effective use of biomass in biorefineries.
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Affiliation(s)
- Lydia Pui Ying Lam
- Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Kyoto 611-0011, Japan
- Center for Crossover Education, Graduate School of Engineering Science, Akita University, Akita, Akita 010-0852, Japan
| | - Yuki Tobimatsu
- Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Shiro Suzuki
- Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Kyoto 611-0011, Japan
- Faculty of Applied Biological Sciences, Graduate School of Natural Science and Technology, and The United Graduate School of Agricultural Science, Gifu University, Gifu, Gifu 501-1193Japan
| | - Takuto Tanaka
- Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Senri Yamamoto
- Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Yuri Takeda-Kimura
- Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Yuriko Osakabe
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8502Japan
| | - Keishi Osakabe
- Faculty of Bioscience and Bioindustry, Tokushima University,Tokushima, Tokushima 770-8503Japan
| | - John Ralph
- Department of Biochemistry, and the U.S. Department of Energy Great Lakes Bioenergy Research Center, Wisconsin Energy Institute, University of Wisconsin, Madison, WI 53726, USA
| | - Laura E Bartley
- Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Kyoto 611-0011, Japan
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA
| | - Toshiaki Umezawa
- Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Kyoto 611-0011, Japan
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Houston K, Learmonth A, Hassan AS, Lahnstein J, Looseley M, Little A, Waugh R, Burton RA, Halpin C. Natural variation in HvAT10 underlies grain cell wall-esterified phenolic acid content in cultivated barley. FRONTIERS IN PLANT SCIENCE 2023; 14:1095862. [PMID: 37235033 PMCID: PMC10206312 DOI: 10.3389/fpls.2023.1095862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 04/06/2023] [Indexed: 05/28/2023]
Abstract
The phenolic acids, ferulic acid and p-coumaric acid, are components of plant cell walls in grasses, including many of our major food crops. They have important health-promoting properties in grain, and influence the digestibility of biomass for industrial processing and livestock feed. Both phenolic acids are assumed to be critical to cell wall integrity and ferulic acid, at least, is important for cross-linking cell wall components, but the role of p-coumaric acid is unclear. Here we identify alleles of a BAHD p-coumaroyl arabinoxylan transferase, HvAT10, as responsible for the natural variation in cell wall-esterified phenolic acids in whole grain within a cultivated two-row spring barley panel. We show that HvAT10 is rendered non-functional by a premature stop codon mutation in half of the genotypes in our mapping panel. This results in a dramatic reduction in grain cell wall-esterifed p-coumaric acid, a moderate rise in ferulic acid, and a clear increase in the ferulic acid to p-coumaric acid ratio. The mutation is virtually absent in wild and landrace germplasm suggesting an important function for grain arabinoxylan p-coumaroylation pre-domestication that is dispensable in modern agriculture. Intriguingly, we detected detrimental impacts of the mutated locus on grain quality traits where it was associated with smaller grain and poorer malting properties. HvAT10 could be a focus for improving grain quality for malting or phenolic acid content in wholegrain foods.
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Affiliation(s)
- Kelly Houston
- Cell and Molecular Sciences, The James Hutton Institute, Scotland, United Kingdom
| | - Amy Learmonth
- Division of Plant Sciences, School of Life Sciences, University of Dundee at The James Hutton Institute, Scotland, United Kingdom
| | - Ali Saleh Hassan
- School of Agriculture, Food and Wine, University of Adelaide, Urrbrae, SA, Australia
| | - Jelle Lahnstein
- School of Agriculture, Food and Wine, University of Adelaide, Urrbrae, SA, Australia
| | - Mark Looseley
- Cell and Molecular Sciences, The James Hutton Institute, Scotland, United Kingdom
| | - Alan Little
- School of Agriculture, Food and Wine, University of Adelaide, Urrbrae, SA, Australia
| | - Robbie Waugh
- Cell and Molecular Sciences, The James Hutton Institute, Scotland, United Kingdom
- Division of Plant Sciences, School of Life Sciences, University of Dundee at The James Hutton Institute, Scotland, United Kingdom
- School of Agriculture, Food and Wine, University of Adelaide, Urrbrae, SA, Australia
| | - Rachel A. Burton
- School of Agriculture, Food and Wine, University of Adelaide, Urrbrae, SA, Australia
| | - Claire Halpin
- Division of Plant Sciences, School of Life Sciences, University of Dundee at The James Hutton Institute, Scotland, United Kingdom
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Chandrakanth NN, Zhang C, Freeman J, de Souza WR, Bartley LE, Mitchell RA. Modification of plant cell walls with hydroxycinnamic acids by BAHD acyltransferases. FRONTIERS IN PLANT SCIENCE 2023; 13:1088879. [PMID: 36733587 PMCID: PMC9887202 DOI: 10.3389/fpls.2022.1088879] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 12/28/2022] [Indexed: 06/18/2023]
Abstract
In the last decade it has become clear that enzymes in the "BAHD" family of acyl-CoA transferases play important roles in the addition of phenolic acids to form ester-linked moieties on cell wall polymers. We focus here on the addition of two such phenolics-the hydroxycinnamates, ferulate and p-coumarate-to two cell wall polymers, glucuronoarabinoxylan and to lignin. The resulting ester-linked feruloyl and p-coumaroyl moities are key features of the cell walls of grasses and other commelinid monocots. The capacity of ferulate to participate in radical oxidative coupling means that its addition to glucuronoarabinoxylan or to lignin has profound implications for the properties of the cell wall - allowing respectively oxidative crosslinking to glucuronoarabinoxylan chains or introducing ester bonds into lignin polymers. A subclade of ~10 BAHD genes in grasses is now known to (1) contain genes strongly implicated in addition of p-coumarate or ferulate to glucuronoarabinoxylan (2) encode enzymes that add p-coumarate or ferulate to lignin precursors. Here, we review the evidence for functions of these genes and the biotechnological applications of manipulating them, discuss our understanding of mechanisms involved, and highlight outstanding questions for future research.
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Affiliation(s)
| | - Chengcheng Zhang
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, United States
| | - Jackie Freeman
- Plant Sciences, Rothamsted Research, West Common, Harpenden, Hertfordshire, United Kingdom
| | | | - Laura E. Bartley
- Institute of Biological Chemistry, Washington State University, Pullman, WA, United States
| | - Rowan A.C. Mitchell
- Plant Sciences, Rothamsted Research, West Common, Harpenden, Hertfordshire, United Kingdom
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