Characterization of GaWRKY1, a cotton transcription factor that regulates the sesquiterpene synthase gene (+)-δ-cadinene synthase-A
Characterization of GaWRKY1, a cotton transcription factor that regulates the sesquiterpene synthase gene (+)-δ-cadinene synthase-A
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DOI：
10.1104/pp.104.038612
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发表时间：
2004-05-01
期刊：
影响因子：
7.4
通讯作者：
Chen, XY
中科院分区：
文献类型：
--
作者：
Xu, YH;Wang, JW;Chen, XY
棉花（+）-δ-杜松烯合酶（CAD 1）是一种倍半萜环化酶，催化倍半萜植物抗毒素（包括棉酚）生物合成的分支点步骤。CAD 1-A是CAD 1基因家族的成员，其启动子含有一个W盒回文序列和两个TGAC重复序列，这两个重复序列是WRKY转录因子的结合位点。我们从亚洲棉中分离了几个WRKY cDNA。其中之一，GaWRKY 1，编码的蛋白质含有一个单一的WRKY结构域和一个假定的N-末端Leu拉链。GaWRKY 1与棉花倍半萜途径相关酶基因相似，在棉酚含量低的无腺体棉花品种中表达下调。GAWRKY 1表现出与CAD 1-A在不同的气生器官中表达的时间和空间模式，包括萼片、柱头、花药和发育中的种子。在悬浮细胞中，GaWRKY 1和CAD 1-A基因的表达和倍半萜醛的生物合成强烈诱导的真菌诱导子制剂和茉莉酸甲酯。在酵母（Saccharomycescerevisiae）单杂交系统和体外实验中，GaWRKY 1与来自CAD 1-A启动子的3 × W-box相互作用。此外，在转基因拟南芥植物中，GaWRKY 1的过表达高度激活了CAD 1-A启动子，烟草（Nicotiana tabacum）叶片中的瞬时测定表明，W-box是这种激活所必需的。这些结果表明，GaWRKY 1参与了棉花倍半萜类化合物生物合成的调控，CAD 1-A是该转录因子的靶基因。
The cotton (+)-delta-cadinene synthase (CAD1), a sesquiterpene cyclase, catalyzes a branch-point step leading to biosynthesis of sesquiterpene phytoalexins, including gossypol. CAD1-A is a member of CAD1 gene family, and its promoter contains a W-box palindrome with two reversely oriented TGAC repeats, which are the proposed binding sites of WRKY transcription factors. We isolated several WRKY cDNAs from Gossypium arboreum. One of them, GaWRKY1, encodes a protein containing a single WRKY domain and a putative N-terminal Leu zipper. Similar to genes encoding enzymes of cotton sesquiterpene pathway, GaWRKY1 was down-regulated in a glandless cotton cultivar that contained much less gossypol. GaWRKY1 showed a temporal and spatial pattern of expression comparable to that of CAD1-A in various aerial organs examined, including sepal, stigma, anther, and developing seeds. In suspension cells, expression of both GaWRKY1 and CAD1-A genes and biosynthesis of sesquiterpene aldehydes were strongly induced by a fungal elicitor preparation and methyl jasmonate. GaWRKY1 interacted with the 3 x W-box derived from CAD1-A promoter in yeast (Saccharomyces cerevisiae) one-hybrid system and in vitro. Furthermore, in transgenic Arabidopsis plants, overexpression of GaWRKY1 highly activated the CAD1-A promoter, and transient assay in tobacco (Nicotiana tabacum) leaves demonstrated that W-box was required for this activation. These results suggest that GaWRKY1 participates in regulation of sesquiterpene biosynthesis in cotton, and CAD1-A is a target gene of this transcription factor.