Isolation and characterization of two pathogen- and salicylic acid-induced genes encoding WRKY DNA-binding proteins from tobacco
Isolation and characterization of two pathogen- and salicylic acid-induced genes encoding WRKY DNA-binding proteins from tobacco
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DOI：
10.1023/a:1006399311615
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发表时间：
2000-01-01
影响因子：
5.1
通讯作者：
Chen, ZX
中科院分区：
文献类型：
--
作者：
Chen, CH;Chen, ZX
病原体和水杨酸（SA）诱导的DNA结合活性最近已被确定在烟草中，这是与以前确定的一类WRKY DNA结合蛋白。为了鉴定与这种DNA结合活性相关的WRKY基因家族的成员，我们试图分离那些由病原体感染诱导的WRKY基因。利用结构域特异性差异显示技术，我们分离了两个烟草WRKY基因tWRKY 3和tWRKY 4，它们在烟草花叶病毒（TMV）感染后能在抗性烟草植株中迅速诱导表达。tWRK 3和tWRKY 4都编码具有单一WRKY结构域的蛋白质，该结构域含有保守的WRKYGQK序列。与其他分离的含有Cys（2）His（2）锌基序的WRKY蛋白不同，tWRKY 3和tWRKY 4似乎含有Cys（2）HisCys锌基序。尽管如此，tWRKY 3和tWRKY 4都能够将DNA分子与其他WRKY蛋白识别的W-box（TTGAC）元件结合。tWRKY 3和tWRKY 4基因的表达不仅可以被TMV感染，而且可以被SA或其生物活性类似物快速诱导，这些SA或其生物活性类似物能够诱导病程相关基因并增强抗性。有趣的是，在表达细菌水杨酸羟化酶基因（nahG）的抗性烟草植物中仍然观察到TMV感染对这两个基因的诱导，尽管诱导水平似乎有所降低。病原体和SA诱导的编码WRKY DNA结合蛋白的基因的鉴定，应有利于未来的研究，这一新的组的DNA结合蛋白的调节和功能。
A pathogen- and salicylic acid (SA)-induced DNA-binding activity has been recently identified in tobacco that is related to a previously identified class of WRKY DNA-binding proteins. To identify members of the WRKY gene family associated with this DNA-binding activity, we have attempted to isolate those WRKY genes that are induced by pathogen infection. Using a domain-specific differential display procedure, we have isolated two tobacco WRKY genes, tWRKY3 and tWRKY4, that are rapidly induced in resistant tobacco plants after infection by tobacco mosaic virus (TMV). Both tWRK3 and tWRKY4 encode proteins with a single WRKY domain that contain the conserved WRKYGQK sequence. Unlike other isolated WRKY proteins that contain the Cys(2)His(2) zinc motif, tWRKY3 and tWRKY4 appear to contain the Cys(2)HisCys zinc motif. Nonetheless, both tWRKY3 and tWRKY4 are capable of binding DNA molecules with the W-box (TTGAC) element recognized by other WRKY proteins. Expression of the tWRKY3 and tWRKY4 genes could be rapidly induced not only by TMV infection but also by SA or its biologically active analogues that are capable of inducing pathogenesis-related genes and enhanced resistance. Interestingly, induction of both genes by TMV infection was still observed in resistant tobacco plants expressing the bacterial salicylate hydroxylase gene (nahG), although the levels of induction appeared to be reduced. Identification of pathogen- and SA-induced genes encoding WRKY DNA-binding proteins should facilitate future studies on the regulation and functions of this novel group of DNA-binding proteins.