Salt-induced transcription factor MYB74 is regulated by the RNA-directed DNA methylation pathway in Arabidopsis.
Salt-induced transcription factor MYB74 is regulated by the RNA-directed DNA methylation pathway in Arabidopsis.
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拟南芥中盐诱导的转录因子 MYB74 受 RNA 指导的 DNA 甲基化途径的调节。
DOI：
10.1093/jxb/erv312
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发表时间：
2015-09
影响因子：
6.9
通讯作者：
Zheng C
中科院分区：
文献类型：
--
作者：
Xu R;Wang Y;Zheng H;Lu W;Wu C;Huang J;Yan K;Yang G;Zheng C
AtMYB74是一个R2R3-MYB基因，通过RdDM转录调控对盐胁迫的响应。针对AtMYB74启动子区域的siRNA的积累对于维持AtMYB74的表达是必不可少的。盐胁迫是全球农业中的主要非生物胁迫之一，它通过干扰基因表达谱和细胞代谢而导致作物歉收。转录因子和RNA引导的DNA甲基化(RdDM)在植物非生物胁迫下的基因激活调控中发挥着重要作用。AtMYB74是R2R3-MYB基因家族中的一员，主要受RdDM转录调控，是拟南芥对盐胁迫的反应。亚硫酸氢盐测序表明，24-NT siRNAs靶向AtMYB74转录起始点上游约500bp的区域，该区域高度甲基化。在盐胁迫下，野生型植物该区域的DNA甲基化水平显著降低，而RdDM突变体没有发现变化。Northern印迹和实时定量逆转录聚合酶链式反应分析表明，盐胁迫下WT植株中24-NT siRNAs的积累减少。进一步的启动子缺失分析表明，siRNA靶区对于维持AtMYB74的表达模式是必不可少的。此外，过量表达AtMYB74的转基因植株在种子萌发过程中表现出对氯化钠的敏感。这些结果表明，5个24-NT siRNAs水平的变化通过RdDM调节AtMYB74转录因子对盐胁迫的响应。
AtMYB74, a R2R3-MYB gene, is transcriptionally regulated through RdDM for response to salt stress. The accumulation of siRNA targeting to the AtMYB74 promoter region is essential for maintaining AtMYB74 expression. Salt stress is one of the major abiotic stresses in agriculture worldwide that causes crop failure by interfering with the profile of gene expression and cell metabolism. Transcription factors and RNA-directed DNA methylation (RdDM) play an important role in the regulation of gene activation under abiotic stress in plants. This work characterized AtMYB74, a member of the R2R3-MYB gene family, which is transcriptionally regulated mainly by RdDM as a response in salt stress in Arabidopsis. Bisulphite sequencing indicated that 24-nt siRNAs target a region approximately 500bp upstream of the transcription initiation site of AtMYB74, which is heavily methylated. Levels of DNA methylation in this region were significantly reduced in wild type plants under salt stress, whereas no changes were found in RdDM mutants. Northern blot and quantitative real-time reverse transcription PCR analysis showed that the accumulation of 24-nt siRNAs was decreased in WT plants under salt stress. Further promoter deletion analysis revealed that the siRNA target region is essential for maintaining AtMYB74 expression patterns. In addition, transgenic plants overexpressing AtMYB74 displayed hypersensitivity to NaCl during seed germination. These results suggest that changes in the levels of the five 24-nt siRNAs regulate the AtMYB74 transcription factor via RdDM in response to salt stress.