Role of the Two-Component Pathway in Mediating Ethylene Signal Transduction

植物激素乙烯在植物生长发育过程中发挥着重要而广泛的作用，包括调节种子萌发、幼苗生长、叶片和花瓣脱落、果实成熟、器官衰老和病原菌反应。单一激素如何调节如此多样化的过程，以及这些过程如何与其他信号通路整合，仍然是植物生物学的基本问题。该项目将探索乙烯调节这些过程的基因表达机制，从而为乙烯信号和调控提供新的见解，以及改变农业上重要植物的乙烯反应的途径。一门名为“绿色世界的秘密”的暑期艺术与科学课程将与该项目相结合，在该课程中，学生将使用科学工具，进行科学思考，并参与将科学与艺术相结合的创造性过程。乙烯信号转导的既定途径最终由EIN3转录因子(TF)家族进行转录调控。有证据表明，乙烯受体也可能通过一条两组分的途径发出信号，利用B型ARR家族的转录因子来控制乙烯反应的一个子集。该项目提供了一套完整的实验，以确定B型ARRs如何与EIN3家族的转录因子协同工作，从而建立对乙烯转录反应的系统水平的理解。这个项目的第一个目标是描述B型ARRs和EIN3之间的物理相互作用在转录调控中的作用。将继续进行机制研究，以阐明这种相互作用的基础，以及这种相互作用如何影响乙烯依赖的基因调控。第二个目标是确定由B型ARRS和EIN3共同调节的一套基因。基于芯片序列和RNA序列的方法将用于识别共同调节的靶标，基于系统的方法将用于预测用于测试的生理角色。第三个目标是表征乙烯和细胞分裂素信号通路之间的转录串扰，因为乙烯途径使用双组分信号元件被预测通过细胞分裂素途径影响信号。TF的协作性和隔离如何调节这些植物激素信号通路之间的串扰的模型将使用转录学和遗传学方法进行测试。

The plant hormone ethylene plays important and wide-ranging roles throughout plant growth and development, including regulation of seed germination, seedling growth, leaf and petal abscission, fruit ripening, organ senescence, and pathogen responses. How a single hormone mediates such a diverse array of processes and how these processes are integrated with other signaling pathways remain fundamental questions in plant biology. This project will explore a gene expression mechanism by which ethylene regulates such processes, thereby providing novel insights into ethylene signaling and regulation as well as avenues by which to modify ethylene responses in agriculturally important plants. A summer art-and-science course titled "Secrets of the Green World" will be developed in conjunction with this project, where students will employ scientific tools, engage in scientific thought, and be involved in a creative process that integrates science with art.The established pathway for ethylene signal transduction culminates in transcriptional regulation by the EIN3 family of transcription factors (TFs). Evidence indicates that the ethylene receptors may also signal through a two-component pathway, employing the type-B ARR family of TFs, to control a subset of the ethylene responses. This project presents an integrated set of experiments to determine how the type-B ARRs function in concert with the EIN3 family of TFs, building toward a systems level understanding of the ethylene transcriptional response. The first objective of this project is to characterize the role of physical interaction between type-B ARRs and EIN3 in transcriptional regulation. Mechanistic studies will be pursued to elucidate the basis for the interaction and how this interaction affects ethylene-dependent gene regulation. The second objective is to determine the suite of genes co-regulated by type-B ARRs and EIN3. ChIP-Seq and RNA-Seq based approaches will be used to identify the co-regulated targets, and systems-based approaches used to predict physiological roles for testing. The third objective is to characterize transcriptional cross-talk between the ethylene and cytokinin signaling pathways, since employment of two-component signaling elements by the ethylene pathway is predicted to affect signaling through the cytokinin pathway. Models for how TF cooperativity and sequestration regulate cross-talk between these phytohormone signaling pathways will be tested using transcriptomic and genetic approaches.