Plant signal transduction and gene expression in response to water stress condition

植物响应水分胁迫的信号转导和基因表达

• 批准号: 17370014
• 负责人: SHINOZAKI Kazuko
• 金额: $ 9.34万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17370014/
• 关键词: water stress; transcriptional legulation; promoter analysis; 水ストレス; water stress; transcriptional legulation; promoter analysis; 水ストレス

Transcription factors DREB1A/CBF3 and DREB2A interact with a cis-acting element, DRE, involved in cold- and drought-stress-responsive gene expression in Arabidopsis. Intact DREB2A expression does not activate downstream genes under normal growth conditions, suggesting that DREB2A requires post-translational modification for activation. DREB2A domain analysis using protoplasts identified a transcriptional activation domain between residues 254 and 335, and deletion of a region between residues 136 and 165 transforms DREB2A to a constitutive active form. Overexpression of constitutive active DREB2A resulted in significant drought stress tolerance but only slight freezing tolerance in transgenic plants. Microarray revealed that DREB2A regulates expression of many water-stress-inducible genes. However, some genes downstream of DREB2A are not downstream of DREB1A, which also recognizes DRE but functions in cold-stress-responsive gene expression. Green fluorescent protein gave a strong signa … More l in the nucleus under unstressed control conditions when fused to constitutive active DREB2A but only a weak signal when fused to full-length DREB2A. The region between DREB2A residues 136 and 165 plays a role in the stability of this protein in the nucleus, which is important for protein activation.Microarray analysis of transgenics overexpressing DREB2A CA also indicated that the overexpression of DREB2A CA induces heat-shock (HS) related genes. Moreover, we found that transient induction of the DREB2A occurs rapidly by HS stress and that the sGFP-DREB2A protein accumulates in nuclei of HS stressed cells. DREB2A upregulated genes were classified into 3 groups based on their expression patterns : genes induced by HS, genes induced by drought stress and genes induced by both HS and drought stress. DREB2A upregulated genes were downregulated in DREB2A knockout mutants under stress conditions. Thermotolerance was significantly increased in the plants overexpressing DREB2A CA and decreased in the DREB2A knockout plants. Collectively, these results indicate that DREB2A functions in both water and HS stress responses. Less

转录因子DREB1A/CBF3和DREB2A与拟南芥中冷和干旱压力反应性基因表达涉及的顺式作用元件DRE相互作用。完整的DREB2A表达不会在正常生长条件下激活下游基因，这表明DREB2A需要翻译后修饰才能激活。使用原生质体的DREB2A结构域分析确定了残留254和335之间的转录激活结构域，以及残差136和165之间的区域的删除将DREB2A转换为本构的活动形式。本构主动DREB2A的过表达导致了明显的干旱胁迫耐受性，但仅在转基因植物中略有冷冻耐受性。微阵列显示DREB2A调节许多水压力诱导基因的表达。但是，Dreb2a下游的某些基因并不是Dreb1a的下游，它也识别DRE，而是在冷压力响应基因表达中的作用。绿色荧光蛋白在核心在无应力的对照条件下融合到本构主动DREB2A时的核中具有很强的符号。 DREB2A之间的区域保留136和165在该核中该蛋白质的稳定性中起作用，这对于蛋白质激活很重要。过表达DREB2A CA的转化分析也表明，DREB2A CA的过表达诱导了热震电（HS）相关基因。此外，我们发现DREB2A的短暂诱导是由HS应力迅速发生的，而SGFP-DREB2A蛋白在HS胁迫细胞的核中积累。 DREB2A更新的基因根据其表达模式分为3组：由HS诱导的基因，由干旱胁迫诱导的基因以及HS和干旱胁迫诱导的基因。在应力条件下，DREB2A更新的基因在Dreb2a敲除突变体中被下调。过表达的Dreb2a Ca的植物中的热耐含量显着增加，并且在DREB2A敲除植物中增加了耐热性。总的来说，这些结果表明DREB2A在水和HS应力反应中均起作用。较少的