Signaling by Ethylene Receptors of Arabidopsis

乙烯是植物体内的一种内源性生长调节因子，影响种子萌发、幼苗生长、衰老和果实成熟。 植物感知和传递乙烯信号的最初步骤已经开始在拟南芥中的研究中得到阐明。 已经发现，植物含有与细菌组氨酸激酶相关的乙烯受体家族。 该受体的下游是MAP激酶途径。 本项目的研究是研究乙烯信号是如何通过受体传导并传递给信号通路中的其他元件的。 植物中乙烯受体的膜定位将通过与绿色荧光蛋白（GFP）的融合体在拟南芥中的表达来确定。 受体的磷酸化活性将在转基因表达和从酵母纯化后进行检查。 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检查。 这项工作将澄清乙烯信号转导的早期步骤，并为这些步骤的工程改造提供了一个框架。 乙烯敏感性的改变将增强我们调节作物的成熟和果实成熟等过程的能力。 这些研究也将有助于理解细菌组氨酸激酶是如何适应真核系统发挥功能的。

The gas ethylene functions as an endogenous growth regulator in plants, affecting seed germination, seedling growth, abscission, senescence and fruit ripening. The initial steps by which plants perceive and transduce the ethylene signal have begun to be elucidated by studies in Arabidopsis thaliana. It has been found that plants contain a family of ethylene receptors that are related to bacterial histidine kinases. Downstream of the receptor is a MAP kinase pathway. The research in this project is studying how the ethylene signal is transduced through the receptor and passed on to other elements in the signaling pathway. The membrane localization of ethylene receptors in plants will be determined by expression of fusions with green fluorescent protein (GFP) in Arabidopsis.Dynamics of receptor expression and localization will be examined by use of biochemical methods in concert with visualization of GFP fusions. Phosphorylation activity of the receptors will be examined after transgenic expression and purification from yeast. The mechanisms of action of the ethylene receptors will be examined by transforming mutant versions back into Arabidopsis and determining how ethylene signal transduction is affected. This work will clarify 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 of crops. These studies will also help to understand how bacterial histidine kinases have been adapted to function in a eukaryotic system.