RNAi-suppression of barley caffeic acid O-methyltransferase modifies lignin despite redundancy in the gene family.
RNAi-suppression of barley caffeic acid O-methyltransferase modifies lignin despite redundancy in the gene family.
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DOI：
10.1111/pbi.13001
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发表时间：
2019-03
影响因子：
13.8
通讯作者：
Halpin C
中科院分区：
文献类型：
--
作者：
Daly P;McClellan C;Maluk M;Oakey H;Lapierre C;Waugh R;Stephens J;Marshall D;Barakate A;Tsuji Y;Goeminne G;Vanholme R;Boerjan W;Ralph J;Halpin C
咖啡酸O-甲基转移酶（COMT）是在玉米和高粱的许多棕中脉高消化率突变体中修饰的木质素生物合成基因，其靶向在小粒温带谷物大麦（大麦）中下调以改善秸秆性质。系统发育和表达分析鉴定了在茎中表达的大麦COMT直向同源物，定义了比短柄草或水稻中更大的基因家族，其中三个COMT基因在木质化组织中表达。RNAi显著降低了茎COMT蛋白和酶活性，并适度降低了茎木质素含量，同时显著改变了木质素结构。木质素的愈创木基与愈创木基的比例降低了约50%，5-羟基愈创木基（5-OH-G）单元以比正常高10 - 15倍的水平掺入木质素中，并且与细胞壁连接的对香豆酸酯的量降低了约50%。在任何RNAi品系中均未观察到棕色中脉表型，尽管存在显著的COMT抑制和木质素改变。大麦中新的COMT基因家族结构突出了草基因组的动态性质。大麦COMTs中的红细胞可以解释大麦和小麦中没有棕色中脉突变体。然而，大麦COMT RNAi系具有开发用于生物能源应用和作为动物饲料的潜力。
Caffeic acid O‐methyltransferase (COMT), the lignin biosynthesis gene modified in many brown‐midrib high‐digestibility mutants of maize and sorghum, was targeted for downregulation in the small grain temperate cereal, barley (Hordeum vulgare), to improve straw properties. Phylogenetic and expression analyses identified the barley COMT orthologue(s) expressed in stems, defining a larger gene family than in brachypodium or rice with three COMT genes expressed in lignifying tissues. RNAi significantly reduced stem COMT protein and enzyme activity, and modestly reduced stem lignin content while dramatically changing lignin structure. Lignin syringyl‐to‐guaiacyl ratio was reduced by ~50%, the 5‐hydroxyguaiacyl (5‐OH‐G) unit incorporated into lignin at 10‐–15‐fold higher levels than normal, and the amount of p‐coumaric acid ester‐linked to cell walls was reduced by ~50%. No brown‐midrib phenotype was observed in any RNAi line despite significant COMT suppression and altered lignin. The novel COMT gene family structure in barley highlights the dynamic nature of grass genomes. Redundancy in barley COMTs may explain the absence of brown‐midrib mutants in barley and wheat. The barley COMT RNAi lines nevertheless have the potential to be exploited for bioenergy applications and as animal feed.
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影响因子：
5.1
作者：
COLLAZO, P;MONTOLIU, L;RIGAU, J
通讯作者：
RIGAU, J
影响因子：
3.1
作者：
Bout, S;Vermerris, W
通讯作者：
Vermerris, W
DOI：
10.1139/b07-098
发表时间：
2007-12-01
期刊：
CANADIAN JOURNAL OF BOTANY-REVUE CANADIENNE DE BOTANIQUE
影响因子：
--
作者：
Hamberger, Bjoern;Ellis, Margaret;Douglas, Carl J.
通讯作者：
Douglas, Carl J.
影响因子：
46.9
作者：
Chen, Fang;Dixon, Richard A.
通讯作者：
Dixon, Richard A.
影响因子：
7.2
作者：
d'Yvoire, Madeleine Bouvier;Bouchabke-Coussa, Oumaya;Sibout, Richard
通讯作者：
Sibout, Richard