Activated Expression of WRKY57 Confers Drought Tolerance in Arabidopsis
Activated Expression of WRKY57 Confers Drought Tolerance in Arabidopsis
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DOI：
10.1093/mp/sss080
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发表时间：
2012-11-01
期刊：
影响因子：
27.5
通讯作者：
Yu, Diqiu
中科院分区：
文献类型：
--
作者：
Jiang, Yanjuan;Liang, Gang;Yu, Diqiu
干旱是限制全球农作物生产力的最严重的环境因素之一。然而，植物耐旱性的机制尚不清楚。已知WRKY转录因子在适应非生物胁迫中起作用。通过筛选WRKY相关的T-DNA插入突变体库，我们分离出一个功能获得性突变体，获得耐旱性（adt），表现出改善的耐旱性。在干旱胁迫条件下，adt积累了较高水平的阿坝比野生型植物。气孔孔径分析表明adt比野生型植株对阿坝更敏感。分子遗传学分析表明，在adt中的T-DNA插入导致WRKY基因的激活表达，该基因编码WRKR 57蛋白。WRKY 57的组成型表达也赋予类似的耐旱性。与高阿坝含量和增强耐旱性相一致，3个胁迫响应基因（RD 29 A，NCED 3和ABA 3）在adt中上调。ChIP检测表明WRKY 57可以直接结合RD 29 A和NCED 3启动子序列的W-box。阿坝处理抑制了adt的种子萌发和幼苗早期生长，而在高渗条件下，adt的种子萌发率较高。综上所述，我们的研究结果表明，WRKY 57的激活表达通过提高阿坝水平来提高拟南芥的耐旱性。WRKY 57基因功能的确定将有助于通过基因操作方法提高植物耐旱性。
Drought is one of the most serious environmental factors that limit the productivity of agricultural crops worldwide. However, the mechanism underlying drought tolerance in plants is unclear. WRKY transcription factors are known to function in adaptation to abiotic stresses. By screening a pool of WRKY-associated T-DNA insertion mutants, we isolated a gain-of-function mutant, acquired drought tolerance (adt), showing improved drought tolerance. Under drought stress conditions, adt accumulated higher levels of ABA than wild-type plants. Stomatal aperture analysis indicated that adt was more sensitive to ABA than wild-type plants. Molecular genetic analysis revealed that a T-DNA insertion in adt led to activated expression of a WRKY gene that encodes the WRKR57 protein. Constitutive expression of WRKY57 also conferred similar drought tolerance. Consistently with the high ABA content and enhanced drought tolerance, three stress-responsive genes (RD29A, NCED3, and ABA3) were up-regulated in adt. ChIP assays demonstrated that WRKY57 can directly bind the W-box of RD29A and NCED3 promoter sequences. In addition, during ABA treatment, seed germination and early seedling growth of adt were inhibited, whereas, under high osmotic conditions, adt showed a higher seed germination frequency. In summary, our results suggested that the activated expression of WRKY57 improved drought tolerance of Arabidopsis by elevation of ABA levels. Establishment of the functions of WRKY57 will enable improvement of plant drought tolerance through gene manipulation approaches.