OsWRKY42 Represses OsMT1d and Induces Reactive Oxygen Species and Leaf Senescence in Rice
OsWRKY42 Represses OsMT1d and Induces Reactive Oxygen Species and Leaf Senescence in Rice
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DOI：
10.14348/molcells.2014.0128
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发表时间：
2014-07-31
影响因子：
3.8
通讯作者：
Jeon, Jong-Seong
中科院分区：
文献类型：
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作者：
Han, Muho;Kim, Chi-Yeol;Jeon, Jong-Seong
从水稻（Oryza sativa L.）WRKY基因，其在衰老叶中高度上调，表示为OsWRKY 42。分析OsWRKY 42-GFP在玉米原生质体中的表达及其对转录激活的影响，表明OsWRKY 42蛋白作为核转录阻遏物起作用。OsWRKY 42过表达（OsWRKY 42 OX）转基因水稻植株表现出叶片早衰表型，活性氧（ROS）、过氧化氢积累和叶绿素含量降低。ROS产生和清除基因的表达分析表明，OsWRKY 42 OX植株中聚集在第12染色体上的金属硫蛋白基因，尤其是OsMT 1d，受到强烈抑制。OsMT 1d启动子：LUC构建体被OsWRKY 42在水稻原生质体中的过表达所抑制。染色质免疫沉淀分析表明OsWRKY 42与OsMT 1d启动子的W-box结合。因此，我们的研究结果表明，OsWRKY 42抑制OsMT 1d介导的ROS清除，从而促进水稻叶片衰老。
We isolated a rice (Oryza sativa L.) WRKY gene which is highly upregulated in senescent leaves, denoted OsWRKY42. Analysis of OsWRKY42-GFP expression and its effects on transcriptional activation in maize protoplasts suggested that the OsWRKY42 protein functions as a nuclear transcriptional repressor. OsWRKY42-overexpressing (OsWR KY42OX) transgenic rice plants exhibited an early leaf senescence phenotype with accumulation of the reactive oxygen species (ROS) hydrogen peroxide and a reduced chlorophyll content. Expression analysis of ROS producing and scavenging genes revealed that the metallothionein genes clustered on chromosome 12, especially OsMT1d, were strongly repressed in OsWRKY42OX plants. An OsMT1d promoter: LUC construct was found to be repressed by OsWRKY42 overexpression in rice protoplasts. Finally, chromatin immunoprecipitation analysis demonstrated that OsWRKY42 binds to the W-box of the OsMT1d promoter. Our results thus suggest that OsWRKY42 represses OsMT1d-mediated ROS scavenging and thereby promotes leaf senescence in rice.