Signaling by Ethylene Receptors of Arabidopsis

MCB-9603679免疫球蛋白 技术 简单气体乙烯作为植物的内源生长调节剂，影响种子萌发、幼苗生长、萌发、衰老、果实成熟和病原菌反应。 植物感知和传递乙烯信号的最初步骤已经开始通过对植物拟南芥的研究来阐明。 从这项工作中，它已被证明，一个家庭的乙烯受体存在于植物中的细菌组氨酸激酶有关。 另外的证据表明，乙烯受体的下游是MAP激酶途径。 因此，原核和真核系统的信号转导元件特征已被组合在一个单一的途径。该研究旨在确定乙烯信号如何通过受体转导并传递到信号通路中的下游元件。 乙烯受体将参照其细菌对应物进行表征。 植物中乙烯受体的膜定位将通过生物化学分级分离方法来确定。 在转基因表达和从细菌和酵母中纯化蛋白质后，将检查假定的受体激酶活性。从转基因酵母中纯化全长乙烯受体将允许分析乙烯的结合如何调节激酶活性。 此外，乙烯受体的作用机制将通过将突变体转化回拟南芥并确定乙烯信号转导如何受到影响来详细研究。 乙烯受体被假设为通过一个反应调节蛋白，饲料到MAP激酶途径的功能，和潜在的反应调节剂已被确定在拟南芥。 它们在乙烯信号转导中的作用将以敲除突变和与途径中已知元件相互作用的能力为特征。 这项工作将澄清乙烯信号转导的早期步骤，并提供了一个框架，工程改造到这些步骤。 乙烯敏感性的改变将增强我们调节具有重要农业意义的作物的成熟和果实成熟等过程的能力。 在更广泛的背景下，这些研究也将有助于阐明细菌组氨酸激酶是如何适应真核系统的功能。 非技术 气体乙烯是一种植物激素，既发出信号，又诱导各种反应，包括成熟和衰老。乙烯从某些细胞中流出，刺激邻近细胞和植物的反应。 乙烯被广泛用于诱导一些水果如番茄的成熟，并且已经显示出乙烯产生的中断延长了现在可商购的转基因番茄的货架期。本项目将研究乙烯如何被靶细胞感知的基本机制。乙烯被植物细胞表面的一种蛋白质检测到，并向细胞发出信号，以刺激介导成熟和衰老反应的许多基因。本计画将阐明乙烯侦测所产生的讯号传递机制。乙烯信号机制的阐明将是理解植物基础生物学的一个重要进展，它将展示在粮食和花卉作物中产生新的和有用的变化以允许控制成熟和更长寿命的产品和花的前景。

MCB-9603679 Schaller Technical The simple gas ethylene functions as an endogenous growth regulator in plants, and affects seed germination, seedling growth, abscission, senescence, fruit ripening, and pathogen responses. The initial steps by which plants perceive and transduce the ethylene signal have begun to be elucidated by studies in the plant Arabidopsis thaliana. From this work it has been demonstrated that a family of ethylene receptors exist in plants that are related to bacterial histidine kinases. Additional evidence indicates that downstream of the ethylene receptors lies a MAP kinase pathway. Thus, signal transduction elements characteristic of both prokaryotic and eukaryotic systems have been combined in a single pathway. The proposed research is designed to determine how the ethylene signal is transduced through the receptor and passed to downstream elements in the signaling pathway. Ethylene receptors will be characterized in reference to their bacterial counterparts. The membrane location of the ethylene receptors in plants will be determined by biochemical fractionation methods. The postulated kinase activity of the receptors will be examined following transgenic expression and purification of the protein from bacteria and yeast. Purification of full-length ethylene receptors from transgenic yeast will allow analysis as to how binding of ethylene regulates kinase activity. In addition, the mechanism of action of the ethylene receptors will be examined in detail by transforming mutant versions back into Arabidopsis and determining how ethylene signal transduction is affected. Ethylene receptors are hypothesized to function through a response regulator protein that feeds into the MAP kinase pathway, and potential response regulators have been identified in Arabidopsis. Their role in ethylene signal transduction will be characterized by knock-out mutations and the ability to interact with known elements in the pathway. This wo rk will clarify the early steps in ethylene signal transduction and provide a framework for engineering modifications into these steps. Modifications of ethylene sensitivity will enhance our ability to regulate such processes as abscission and fruit-ripening in crops of agronomic importance. In a broader context, these studies will also help elucidate how the bacterial histidine kinases have been adapted to function in a eukaryotic system. Nontechnical The gas ethylene is a plant hormone that both signals and induces a variety of responses including ripening and senescence. The efflux of ethylene from some cells stimulates the response of adjacent cells and plants. Ethylene is widely used to induce ripening of some fruit such as tomato and the interruption of ethylene production has been shown to extend the shelf life of transgenic tomatoes that are now commercially available. This project will investigate the fundamental mechanism of how ethylene is perceived by targeted cells. Ethylene is detected by a protein on the surface of plant cells and signals the cell to undertake the stimulation of a number of genes that mediate the ripening and senesence response. This project will elucidate the mechanism of signaling that occurs as a consequence of ethylene detection. The elucidation of the signaling mechanism for ethylene will be an important advance in the understanding of the fundamental biology of plants and it will present the prospect of producing new and useful changes in food and floral crops to permit controlled ripening and longer-lived produce and flowers.