Overexpression of a WRKY Transcription Factor TaWRKY2 Enhances Drought Stress Tolerance in Transgenic Wheat
Overexpression of a WRKY Transcription Factor TaWRKY2 Enhances Drought Stress Tolerance in Transgenic Wheat
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DOI：
10.3389/fpls.2018.00997
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发表时间：
2018-08-07
影响因子：
5.6
通讯作者：
Zhang, Zhengbin
中科院分区：
文献类型：
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作者：
Gao, Huiming;Wang, Yafei;Zhang, Zhengbin
干旱是严重制约植物生长和作物产量的主要环境胁迫。先前的研究表明，来自小麦（Triticum aestivum）的TaWRKY2在干旱胁迫耐受性中起重要作用。在本研究中，我们分离了TaWRKY2的启动子，并确定了启动子区域的多个调控顺式元件。TaWRKY2启动子的活性受到干旱、盐、热和脱落酸（阿坝）的诱导。我们还产生了TaWRKY2过表达的转基因小麦，并发现转基因幼苗表现出显着增强的耐旱性，证明了较高的存活率和较低的水分流失率的离体叶片相比，野生型（WT）植物。此外，转基因株系具有较高的游离脯氨酸、可溶性糖和叶绿素含量。在抽穗期之前的干旱胁迫的延长期间，WT植物的生长受到抑制，而TaWRKY2过表达系进展到抽穗期。转基因小麦籽粒产量的增加反映了穗长、穗粒数和地上生物量的累积效应。研究结果表明，TaWRKY2基因能够提高小麦的耐旱性，增加小麦产量，为通过基因工程改良小麦品种的耐旱性提供了一个有希望的候选靶基因。
Drought is a major environmental stress that severely restricts plant growth and crop productivity. A previous study showed that TaWRKY2 from wheat (Triticum aestivum) plays an important role in drought stress tolerance. In the present study, we isolated the promoter of TaWRKY2 and identified multiple regulatory cis-elements in the promoter region. The activity of the TaWRKY2 promoter was induced by drought, salt, heat, and abscisic acid (ABA). We also generated TaWRKY2-overexpressing transgenic wheat, and found that the transgenic seedlings exhibited significantly enhanced tolerance to drought stress, as evidenced by a higher survival rate and lower water loss rate of detached leaves compared with wild type (WT) plants. In addition, the transgenic lines had higher contents of free proline, soluble sugar, and chlorophyll. During a prolonged period of drought stress before the heading stage, the growth of WT plants was inhibited, whereas the TaWRKY2-overexpressing lines progressed to the heading stage. The increased grain yield of the transgenic wheat lines reflected the cumulative effects of longer panicle length, more kernels per spike, and greater aboveground biomass. Our findings show that TaWRKY2 can enhance drought tolerance and increase grain yield in wheat, thus providing a promising candidate target for improving the drought tolerance of wheat cultivars through genetic engineering.