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Title: Downregulation of p- COUMAROYL ESTER 3-HYDROXYLASE in rice leads to altered cell wall structures and improves biomass saccharification

p-Coumaroyl ester 3-hydroxylase (C3'H) is a key enzyme involved in the biosynthesis of lignin, a phenylpropanoid polymer that is the major constituent in vascular plants’ secondary cell walls. Although the crucial role of C3'H in lignification and its manipulation to upgrade lignocellulose have been investigated in eudicots, limited information is available in monocotyledonous grass species despite their potential as biomass feedstocks. Here in this paper we address the pronounced impacts of C3'H-deficiency on the structure and properties of grass cell walls. C3'H-knockdown lines generated via RNAi-mediated gene silencing, with ~0.5% of residual expression levels, reached maturity and set seeds, whereas, in contrast, C3'H-knockout rice mutants generated via CRISPR/Cas9-mediated mutagenesis were severely dwarfed and sterile. Cell wall analysis of the mature C3'H-knockdown RNAi lines revealed that their lignins were largely enriched in p-hydroxyphenyl (H) units while substantially reduced in the normally dominant guaiacyl (G) and syringyl (S) units. Interestingly, however, the enrichment of H units was limited to being within the non-acylated lignin units, with grass-specific γ-p-coumaroylated lignin units remaining apparently unchanged. Suppression of C3'H also resulted in relative augmentation in tricin residues in lignin as well as substantial reduction in wall cross-linking ferulates. Collectively, our data demonstrate that C3'H expressionmore » is an important determinant, not only of lignin content and composition, but also of the degree of cell wall cross-linking. We also demonstrated that C3'H-suppressed rice displays enhanced biomass saccharification.« less
Authors:
 [1] ; ORCiD logo [1] ;  [2] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [3] ;  [4] ;  [5] ;  [6]
  1. Kyoto Univ. (Japan). Research Inst. for Sustainable Humanosphere
  2. Univ. of Wisconsin, Madison, WI (United States). USDOE Great Lakes Bioenergy Research Center; Univ. of Wisconsin, Madison, WI (United States). Dept. of Biochemistry
  3. Tokushima Univ., Kuramoto-cho, Tokushima (Japan). Faculty of Bioscience and Bioindustry
  4. Univ. of Wisconsin, Madison, WI (United States). USDOE Great Lakes Bioenergy Research Center; Univ. of Wisconsin, Madison, WI (United States). Dept. of Biochemistry
  5. Kyoto Univ. (Japan). Graduate School of Agriculture
  6. Kyoto Univ. (Japan). Research Inst. for Sustainable Humanosphere; Kyoto Univ. (Japan). Research Unit for Development of Global Sustainability
Publication Date:
Grant/Contract Number:
SC0018409; FC02-07ER64494
Type:
Accepted Manuscript
Journal Name:
The Plant Journal
Additional Journal Information:
Journal Volume: 95; Journal Issue: 5; Journal ID: ISSN 0960-7412
Publisher:
Society for Experimental Biology
Research Org:
Univ. of Wisconsin, Madison, WI (United States). USDOE Great Lakes Bioenergy Research Center
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; lignin; grass; Oryza sativa; RNAi; CRISPR/Cas9; saccharification; p-coumarate; ferulate; NMR; DFRC
OSTI Identifier:
1459572
Alternate Identifier(s):
OSTI ID: 1459711

Takeda, Yuri, Tobimatsu, Yuki, Karlen, Steven D., Koshiba, Taichi, Suzuki, Shiro, Yamamura, Masaomi, Murakami, Shinya, Mukai, Mai, Hattori, Takefumi, Osakabe, Keishi, Ralph, John, Sakamoto, Masahiro, and Umezawa, Toshiaki. Downregulation of p-COUMAROYL ESTER 3-HYDROXYLASE in rice leads to altered cell wall structures and improves biomass saccharification. United States: N. p., Web. doi:10.1111/tpj.13988.
Takeda, Yuri, Tobimatsu, Yuki, Karlen, Steven D., Koshiba, Taichi, Suzuki, Shiro, Yamamura, Masaomi, Murakami, Shinya, Mukai, Mai, Hattori, Takefumi, Osakabe, Keishi, Ralph, John, Sakamoto, Masahiro, & Umezawa, Toshiaki. Downregulation of p-COUMAROYL ESTER 3-HYDROXYLASE in rice leads to altered cell wall structures and improves biomass saccharification. United States. doi:10.1111/tpj.13988.
Takeda, Yuri, Tobimatsu, Yuki, Karlen, Steven D., Koshiba, Taichi, Suzuki, Shiro, Yamamura, Masaomi, Murakami, Shinya, Mukai, Mai, Hattori, Takefumi, Osakabe, Keishi, Ralph, John, Sakamoto, Masahiro, and Umezawa, Toshiaki. 2018. "Downregulation of p-COUMAROYL ESTER 3-HYDROXYLASE in rice leads to altered cell wall structures and improves biomass saccharification". United States. doi:10.1111/tpj.13988.
@article{osti_1459572,
title = {Downregulation of p-COUMAROYL ESTER 3-HYDROXYLASE in rice leads to altered cell wall structures and improves biomass saccharification},
author = {Takeda, Yuri and Tobimatsu, Yuki and Karlen, Steven D. and Koshiba, Taichi and Suzuki, Shiro and Yamamura, Masaomi and Murakami, Shinya and Mukai, Mai and Hattori, Takefumi and Osakabe, Keishi and Ralph, John and Sakamoto, Masahiro and Umezawa, Toshiaki},
abstractNote = {p-Coumaroyl ester 3-hydroxylase (C3'H) is a key enzyme involved in the biosynthesis of lignin, a phenylpropanoid polymer that is the major constituent in vascular plants’ secondary cell walls. Although the crucial role of C3'H in lignification and its manipulation to upgrade lignocellulose have been investigated in eudicots, limited information is available in monocotyledonous grass species despite their potential as biomass feedstocks. Here in this paper we address the pronounced impacts of C3'H-deficiency on the structure and properties of grass cell walls. C3'H-knockdown lines generated via RNAi-mediated gene silencing, with ~0.5% of residual expression levels, reached maturity and set seeds, whereas, in contrast, C3'H-knockout rice mutants generated via CRISPR/Cas9-mediated mutagenesis were severely dwarfed and sterile. Cell wall analysis of the mature C3'H-knockdown RNAi lines revealed that their lignins were largely enriched in p-hydroxyphenyl (H) units while substantially reduced in the normally dominant guaiacyl (G) and syringyl (S) units. Interestingly, however, the enrichment of H units was limited to being within the non-acylated lignin units, with grass-specific γ-p-coumaroylated lignin units remaining apparently unchanged. Suppression of C3'H also resulted in relative augmentation in tricin residues in lignin as well as substantial reduction in wall cross-linking ferulates. Collectively, our data demonstrate that C3'H expression is an important determinant, not only of lignin content and composition, but also of the degree of cell wall cross-linking. We also demonstrated that C3'H-suppressed rice displays enhanced biomass saccharification.},
doi = {10.1111/tpj.13988},
journal = {The Plant Journal},
number = 5,
volume = 95,
place = {United States},
year = {2018},
month = {6}
}