Divergent and Overlapping Function of Five 4-Coumarate/Coenzyme A Ligases from Populus tomentosa
Divergent and Overlapping Function of Five 4-Coumarate/Coenzyme A Ligases from Populus tomentosa
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毛白杨中五种 4-香豆酸/辅酶 A 连接酶的发散和重叠功能
DOI：
10.1007/s11105-014-0803-4
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发表时间：
2015-08
影响因子：
2.1
通讯作者：
Lu, Hai
中科院分区：
文献类型：
--
作者：
Zhang, Yongzhuo;Cao, Shan;Jiang, Xiangning;Lu, Hai
摘要4-香豆酸/辅酶A连接酶(4CL)在植物次生化合物的生物合成过程中起着关键作用，是从一般苯丙烷代谢到木质素和类黄酮类等几个主要分支途径的分歧点。本研究克隆并鉴定了毛白杨的5个4CL基因。定量聚合酶链式反应和启动子-β-葡萄糖醛酸苷酶分析表明，Pto4CLs的表达存在明显的差异和一定的重叠。这五种Pto4CL重组蛋白也具有不同的底物特异性和催化转化率。与其他Pto4CL蛋白相比，Pto4Cl4具有最高的底物亲和力和催化转化率。5种Pto4CL重组蛋白均未检测到对芥子酸的活性。Pto4CL突变体中V338残基的缺失导致了对芥子酸的活性。芥子酸的低积累和S单元木质素的高比例表明，4CL催化芥子酸活化的能力不是木质素生物合成所必需的。利用35S启动子在转基因烟草中过表达5个Pto4CLs后，韧皮部、木质部、根和叶组织中木质素含量显著增加，羟基肉桂酸衍生物含量显著降低。转Pto4CL4基因烟草根系中的柚皮素含量也有所增加。我们的结果表明，底物特异性和Pto4CL异构体的差异和重叠表达模式可能在调节木质素和类黄酮的生物合成中发挥重要作用。
Abstract4-Coumarate/coenzyme A ligases (4CLs) play key roles in the biosynthesis of plant secondary compounds and act at the divergence point from general phenylpropanoid metabolism to several major branch pathways, such as lignins and flavonoids. In this study, five 4CL genes in Populus tomentosa were cloned and characterized. Quantitative polymerase chain reaction (qPCR) and promoter-β-glucuronidase analysis showed that the expression of Pto4CLs is significantly divergent and certainly overlapping. The five Pto4CL recombinant proteins also have different substrate specificities and catalytic turnover rates. Pto4CL4 has the highest substrate affinity and catalytic turnover rate compared with other Pto4CL proteins. All five Pto4CL recombinant proteins had no detectable activity towards sinapate. Deletion of V338 residues in Pto4CL mutants resulted in activity towards sinapate. The low accumulation of sinapate and high proportion of S unit lignin implies that the ability of 4CL to catalyze the activation of sinapate is not necessary for lignin biosynthesis. Overexpression of the five Pto4CLs in transgenic tobacco using the 35S promoter revealed significantly increased lignin contents and decreased hydroxycinnamate derivative contents in phloem, xylem, root, and leaf tissues. An increased content of naringenin in Pto4CL4 transgenic tobacco roots was also observed. Our results suggest that the substrate specificity and divergent and overlapping expression patterns of Pto4CL isoforms may play important roles in regulating the lignin and flavonoid biosynthesis.
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影响因子：
2.9
作者：
Katsuyoshi Hamada;Y. Tsutsumi;Kazuchika Yamauchi;K. Fukushima;T. Nishida
通讯作者：
Katsuyoshi Hamada;Y. Tsutsumi;Kazuchika Yamauchi;K. Fukushima;T. Nishida
影响因子：
3.7
作者：
Cukovic, D;Ehlting, J;Douglas, CJ
通讯作者：
Douglas, CJ
转基因烟草中毛白杨4-香豆酸辅酶A连接酶Pto4CL2启动子指导的时空表达模式分析
影响因子：
2.8
作者：
Pan, Xiang;Li, Huanhuan;Lu, Hai
通讯作者：
Lu, Hai
影响因子：
2.7
作者：
Lu, H;Zhao, YL;Jiang, XN
通讯作者：
Jiang, XN
影响因子：
3.9
作者：
KNOBLOCH, KH;HAHLBROCK, K
通讯作者：
HAHLBROCK, K