紫花苜蓿盐胁迫响应WRKY转录因子的克隆及表达特征分析

Cloning and expression analysis of WRKY transcription factor involved in salinity stress in alfalfa

WRKY转录因子在植物生长发育及逆境胁迫应答中发挥着核心调控作用,但在紫花苜蓿中的相关研究还鲜有报道。通过对紫花苜蓿盐胁迫转录组测序数据分析,筛选了12个盐诱导或抑制的WRKY家族转录因子并结合其近缘物种的参考序列成功对它们的全长编码序列进行了克隆。获得的目标基因均含有WRKY家族核心保守序列且分布在WRKY家族的不同系统进化分支;它们的表达呈现出明显的组织特异性且均具有转录激活活性。进一步对它们在盐胁迫不同时间下的表达模式进行了分析,结果表明MsWRKY1/3等10个基因受到了盐胁迫诱导,但表达模式表现出多样性, MsWRKY2的表达受到盐胁迫抑制, MsWRKY11的表达在对照及盐胁迫下并没有显著变化。本研究将为深入了解WRKY家族转录因子在紫花苜蓿盐胁迫应答中的调控机制以及牧草作物的遗传育种等方面提供重要的基因资源。

WRKY transcription factors play a key regulatory role in plant development and stress response, but few studies in these areas have been reported in alfalfa. Twelve salinity induced or suppressed WRKY transcriptional factors were identified from the transcriptome sequencing data of salinity stressed alfalfa in this study. Their full length of the coding sequence were cloned based on the reference sequence of the related species. All of the target genes contained the core sequence and they distributed in different evolutionary branches of WRKY family. Their expression showed an obvious tissue specificity. All of them had transcriptional activity. The expression patterns of them under salt stress for different periods showed that among the 12 transcription factors, 10 genes, such as MsWRKY1/3 were induced by salinity stress, but their expression showed a diversified feature. The expression of MsWRKY2 was inhibited but MsWRKY11 was not significantly changed under the control and salt stressed condition. This study will provide important gene resources for understanding the regulatory mechanism of WRKY transcription factors as well as for the genetic breeding of alfalfa.