Functional characterization of Arabidopsis NaCl-inducible WRKY25 and WRKY33 transcription factors in abiotic stresses
Functional characterization of Arabidopsis NaCl-inducible WRKY25 and WRKY33 transcription factors in abiotic stresses
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DOI：
10.1007/s11103-008-9408-3
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发表时间：
2009-01-01
影响因子：
5.1
通讯作者：
Deyholos, Michael K.
中科院分区：
文献类型：
--
作者：
Jiang, Yuanqing;Deyholos, Michael K.
先前的拟南芥根的微阵列分析确定了两个密切相关的WRKY转录因子（WRKY25和WRKY33）的转录本中增加的丰度与NaCl处理后。在这里，我们报告了这些基因的进一步表征，我们发现这些基因可以通过各种非生物胁迫以SOS途径独立的方式诱导，尽管WRKY33的诱导依赖于阿坝信号传导。在根和叶中检测到这两个基因的转录本，而在茎和花芽中分别观察到WRKY25和WRKY33的特定富集模式。我们还确定了上游基因间区域，从每个基因，足以赋予压力诱导的报告基因的表达。然而，在任何测定条件下，wrky25无效突变体的胁迫敏感性与野生型没有差异，而wrky33无效突变体和wrky25wrky33双突变体仅显示出NaCl敏感性的适度增加，表明与其他转录因子的功能冗余。然而，WRKY25或WRKY33的过表达足以增加拟南芥的NaCl耐受性，同时增加对阿坝的敏感性。通过对相关基因型的微阵列分析，我们分别鉴定了31个和208个WRKY25和WRKY33的潜在下游靶标，其中大部分在其上游区域含有W盒。
Previous microarray analyses of Arabidopsis roots identified two closely related WRKY transcription factors (WRKY25 and WRKY33) among the transcripts that increased in abundance following treatment with NaCl. Here, we report further characterization of these genes, which we found to be inducible by a variety of abiotic stresses in an SOS-pathway independent manner, although WRKY33 induction was dependent on ABA signaling. Transcripts of both genes were detected in roots and leaves, while specific patterns of enrichment were observed in stems and floral buds for WRKY25 and WRKY33, respectively. We also identified upstream intergenic regions from each gene that were sufficient to confer stress-inducible expression on a reporter gene. However, the stress sensitivity of wrky25 null mutants did not differ from wild-type under any assay condition, while wrky33 null mutants and wrky25wrky33 double mutants showed only a moderate increase in NaCl-sensitivity, suggesting functional redundancy with other transcription factors. Nevertheless, overexpression of WRKY25 or WRKY33 was sufficient to increase Arabidopsis NaCl tolerance, while increasing sensitivity to ABA. Through microarray analyses of relevant genotypes, we identified 31 and 208 potential downstream targets of WRKY25 and WRKY33, respectively, most of which contained a W-box in their upstream regions.