Functional analysis of a cinnamyl alcohol dehydrogenase involved in lignin biosynthesis in wheat.
Functional analysis of a cinnamyl alcohol dehydrogenase involved in lignin biosynthesis in wheat.
复制标题
参与小麦木质素生物合成的肉桂醇脱氢酶的功能分析
DOI：
10.1093/jxb/erq107
复制
发表时间：
2010-06
影响因子：
6.9
通讯作者：
Ma QH
中科院分区：
文献类型：
--
作者：
Ma QH
肉桂醇脱氢酶（CAD）催化木质素单体生物合成的最后一步。在本研究中，从小麦中分离到一个编码CAD的cDNA，命名为TaCAD 1。在小麦EST数据库中的全基因组数据挖掘揭示了另外10个CAD样同源物，即TaCAD 2至TaCAD 11。系统发育分析表明TaCAD 1属于真正的CAD组参与木质素的合成。另外两个来自小麦基因组的推定的CAD（TaCAD 2和TaCAD 4）也属于这一组，并且非常接近TaCAD 1，但缺乏C-末端结构域，表明它们是假基因。DNA凝胶印迹分析表明，TaCAD 1基因在小麦基因组中有2 ~ 3个拷贝，而RNA凝胶印迹分析表明，TaCAD 1基因在小麦基因组中只有一条带，在茎中表达量高，在叶中表达量低，在根中表达量低。TaCAD 1的三维结构与AtCAD 5相似，但在底物结合区有两个氨基酸发生了替换。重组TaCAD 1蛋白以松柏醛为底物，对芥子醛和对香豆醛也有较高的降解效率。TaCAD 1是一种pH依赖性和温度敏感性的酶，具有典型的随机催化机制。在乳熟期，抗倒伏品种（H4546）茎组织中TaCAD 1 mRNA丰度、蛋白质水平和酶活性均高于抗倒伏品种（C6001）。这些特性与两个品种的木质素含量和倒伏指数相关。这些数据表明TaCAD 1是小麦茎中木质素生物合成的主要CAD，并且对于抗倒伏性至关重要。
Cinnamyl alcohol dehydrogenase (CAD) catalyses the final step in the biosynthesis of monolignols. In the present study, a cDNA encoding a CAD was isolated from wheat, designated as TaCAD1. A genome-wide data mining in the wheat EST database revealed another 10 CAD-like homologues, namely TaCAD2 to TaCAD11. A phylogenetic analysis showed that TaCAD1 belonged to the bona fide CAD group involved in lignin synthesis. Two other putative CADs from the wheat genome (TaCAD2 and TaCAD4) also belonged to this group and were very close to TaCAD1, but lacked C-terminal domain, suggesting that they are pseudogenes. DNA gel blot analysis for the wheat genome showed two to three copies of CAD related to TaCAD1, but RNA gel blot analysis revealed only single band for TaCAD1, which was highly expressed in stem, with quite low expression in leaf and undetectable expression in root. The predicted three-dimension structure of TaCAD1 resembled that of AtCAD5, but two amino acid substitutions were identified in the substrate binding region. Recombinant TaCAD1 protein used coniferyl aldehyde as the most favoured substrate, also showed high efficiencies toward sinapyl and p-coumaryl aldehydes. TaCAD1 was an enzyme being pH-dependent and temperature-sensitive, and showing a typical random catalysing mechanism. At the milky stage of wheat, TaCAD1 mRNA abundance, protein level and enzyme activity in stem tissues were higher in a lodging-resistant cultivar (H4546) than in lodging-sensitive cultivar (C6001). These properties were correlated to the lignin contents and lodging indices of the two cultivars. These data suggest that TaCAD1 is the predominant CAD in wheat stem for lignin biosynthesis and is critical for lodging resistance.
登录
查看更多内容
影响因子：
4.3
作者：
GOFFNER, D;JOFFROY, I;BOUDET, AM
通讯作者：
BOUDET, AM
影响因子：
3.7
作者：
Ma, QH;Tian, B
通讯作者：
Tian, B
影响因子：
3.9
作者：
ECKENRODE, VK;ARNOLD, J;MEAGHER, RB
通讯作者：
MEAGHER, RB
小麦咖啡酸 3-O-甲基转移酶的表征及其在木质素生物合成中的功能。
影响因子：
3.9
作者：
Ma, Qing-Hu;Xu, Yang
通讯作者：
Xu, Yang
与小麦茎发育相关的肉桂酰辅酶 A 还原酶的表征
影响因子：
6.9
作者：
Ma, Qing-Hu
通讯作者：
Ma, Qing-Hu