MAP Kinase in Plant Disease Resistance Signaling Pathway

植物抗病信号通路中的 MAP 激酶

• 批准号: 9974796
• 负责人: Shuqun Zhang
• 金额: $ 33万
• 依托单位: University of Missouri-Columbia
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-01 至 2003-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9974796&HistoricalAwards=false
• 关键词: MAP; Kinase; Plant; Disease; Resistance

Protein phosphorylation and dephosphorylation play important roles in plant disease resistance at multiple steps from the perception of invading pathogens to the activation of plant defense responses. WIPK, a tobacco mitogen-activated protein kinase (MAPK) is activated during resistance responses initiated by either non-host specific elicitors or 'gene-for-gene' interactions. Furthermore, induction of WIPK mRNA and protein occur systemically and correlates with the establishment of systemic acquired resistance (SAR). Extensive recent research in yeast and animals demonstrated that MAPK cascades are major pathways that transduce extracellular stimuli, including various stresses, into cellular responses. In contrast to all other characterized MAPKs that pre-exist in cells and require only phosphorylation activation, WIPK activation requires both post-translational phosphorylation and a preceding gene transcription and de novo synthesis of WIPK protein. Very interestingly, the activation of WIPK gene is mediated by H2O2, another important signaling molecule in plant defense responses.The goal of this project is to functionally define the role(s) of WIPK in both local and systemic resistance. A combination of molecular, biochemical and genetic approaches will be utilized to address this goal. To elucidate the function of WIPK, the upstream kinase of WIPK, WIPK kinase (WIPKK), that phosphorylates and activates WIPK, will be identified. In vivo WIPK activity will then be manipulated by overexpressing a constitutively active WIPKK mutant. The phenotypic change of such transgenic plants in response to pathogens or elicitors should provide the first functional definition of WIPK. To compliment the "gain-of-function" study, "loss-of-function" transgenic lines with suppressed WIPK or WIPKK expression and/or activation will be attempted by using anti-sense, co-suppression and overexpression of dominant negative mutant kinase. In addition, orthologs of WIPK and WIPKK in Arabidopsis will be identified which will facilitate the isolation of knock-out plants from T-DNA insertional mutant pools. One practical extension of this work is that the identification of an important regulatory component in the plant defense signaling pathway may lead to the engineering of crop plants with enhanced disease resistance. The development of such a strategy, which is based on the enhancement of the plant's own defenses, is important for sustaining agricultural production and improving the quality of our environment. Insights into the WIPK cascade should also provide a basis for (1) studying the regulation of plant MAPKs involved in responses to other stresses (e.g. cold, salt, and drought) or phytohormones (e.g. ethylene, auxin and ABA), (2) comparing stress-activated MAPKs in plants, yeast and mammals, (3) identifying unique aspects in the regulation and function of plant MAPKs. Equally important, understanding the role of WIPK, a regulatory component down-stream of H2O2, will greatly extend our knowledge about the signaling role of the oxidative burst in both local resistance and establishment of SAR.

蛋白质磷酸化和去磷酸化在植物抗病性中起着重要作用，从感知入侵病原体到激活植物防御反应的多个步骤。 WIPK是烟草丝裂原活化蛋白激酶（MAPK），在非寄主特异性激发子或基因对基因相互作用引发的抗性反应中被激活。 此外，WIPK mRNA和蛋白的诱导系统地发生，并与系统获得性抗性（SAR）的建立相关。 最近在酵母和动物中的广泛研究表明，MAPK级联是将包括各种应激在内的细胞外刺激转化为细胞反应的主要途径。 与预先存在于细胞中并且仅需要磷酸化活化的所有其他表征的MAPK相反，WIPK活化需要翻译后磷酸化和WIPK蛋白的先前基因转录和从头合成。 WIPK基因的激活是由植物防御反应中的另一个重要信号分子H_2O_2介导的，本研究的目的是从功能上明确WIPK在植物局部抗性和系统抗性中的作用。 将利用分子、生物化学和遗传方法的组合来实现这一目标。 为了阐明WIPK的功能，将鉴定磷酸化和激活WIPK的WIPK上游激酶，WIPK激酶（WIPKK）。然后通过过表达组成型活性WIPKK突变体来操纵体内WIPK活性。 这种转基因植物响应病原体或激发子的表型变化应该提供WIPK的第一个功能定义。 为了补充“功能获得”研究，将通过使用显性失活突变激酶的反义、共抑制和过表达来尝试具有抑制的WIPK或WIPKK表达和/或激活的“功能丧失”转基因系。 此外，将鉴定拟南芥中WIPK和WIPKK的直系同源物，这将有助于从T-DNA插入突变体库中分离敲除植物。这项工作的一个实际延伸是，在植物防御信号通路中的重要调控组分的鉴定可能导致具有增强的抗病性的作物植物的工程。 这种以增强植物自身防御为基础的战略的发展，对于维持农业生产和改善我们的环境质量至关重要。 对WIPK级联反应的深入了解还应为以下工作提供基础：（1）研究参与响应其他胁迫（例如寒冷、盐和干旱）或植物激素（例如乙烯、生长素和阿坝）的植物MAPKs的调节，（2）比较植物、酵母和哺乳动物中胁迫激活的MAPKs，（3）确定植物MAPKs调节和功能的独特方面。 同样重要的是，了解WIPK的作用，一个监管组件下游的H2 O2，将大大扩展我们的知识的信号作用的氧化爆发在本地电阻和建立SAR。