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Os MYB 108 loss‐of‐function enriches p ‐coumaroylated and tricin lignin units in rice cell walls
Author(s) -
Miyamoto Takuji,
Takada Rie,
Tobimatsu Yuki,
Takeda Yuri,
Suzuki Shiro,
Yamamura Masaomi,
Osakabe Keishi,
Osakabe Yuriko,
Sakamoto Masahiro,
Umezawa Toshiaki
Publication year - 2019
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.14290
Subject(s) - tricin , lignin , myb , oryza sativa , mutant , genetically modified rice , cell wall , chemistry , biomass (ecology) , biochemistry , botany , gene , biology , transgene , genetically modified crops , gene expression , organic chemistry , agronomy , flavonoid , antioxidant
Summary Breeding approaches to enrich lignins in biomass could be beneficial to improving the biorefinery process because lignins increase biomass heating value and represent a potent source of valuable aromatic chemicals. However, despite the fact that grasses are promising lignocellulose feedstocks, limited information is yet available for molecular‐breeding approaches to upregulate lignin biosynthesis in grass species. In this study, we generated lignin‐enriched transgenic rice ( Oryza sativa ), a model grass species, via targeted mutagenesis of the transcriptional repressor Os MYB 108 using CRISPR /Cas9‐mediated genome editing. The Os MYB 108 ‐knockout rice mutants displayed increased expressions of lignin biosynthetic genes and enhanced lignin deposition in culm cell walls. Chemical and two‐dimensional nuclear magnetic resonance ( NMR ) analyses revealed that the mutant cell walls were preferentially enriched in γ‐ p ‐coumaroylated and tricin lignin units, both of which are typical and unique components in grass lignins. NMR analysis also showed that the relative abundances of major lignin linkage types were altered in the Os MYB 108 mutants.