Signal Integration of the Ethylene and Cytokinin Hormonal Pathways

乙烯和细胞分裂素是调节许多重要农艺性状的植物激素，包括果实成熟、粮食产量、茎和根结构、衰老、抗病性和抗旱性。尽管这两种激素经常相互对抗，乙烯通常被认为是一种促进植物组织衰老的激素，而细胞分裂素则促进植物变绿，但这两种激素有时也会以合作的方式起作用。该项目的目标是揭示这两种激素如何在植物生长发育的调节中相互作用。更好地了解植物激素信号将使作物优化，以提高其在各种农业环境中的表现。该研究项目将为研究生和博士后提供良好的培训机会。此外，通过当地的合作伙伴关系，该项目将建立一个暑期项目，旨在通过将科学与艺术相结合的参与性活动来发展教育和科学意识。本研究项目提出了一套完整的实验来阐明乙烯和细胞分裂素信号通路之间的转录串扰机制，建立对这一过程的系统级理解。本研究的重点是分别调控乙烯和细胞分裂素主要转录反应的转录因子EIN3和b型ARR家族。第一个目标是表征EIN3和b型ARR转录因子之间的组合相互作用在基因表达调控中的作用，初步结果支持合作和拮抗相互作用。该项目的第二个目标是表征EIN3和a型ARRs之间的物理相互作用在调节EIN3和乙烯信号传导活性中的作用。a型ARRs是细胞分裂素强烈诱导表达的负调节因子家族。第三个目标是表征乙烯在激活b型ARRs中独立于细胞分裂素信号通路的作用，细胞分裂素信号通路是调节乙烯反应子集的另一种途径。这些研究将采用RNA-Seq和ChIP-Seq方法，对转录因子的基因表达和靶标结合进行全局分析。从这些研究中得出的相互作用模型将通过机制、转录组学和遗传学方法进行测试，并将其置于乙烯和细胞分裂素在幼苗生长中的作用的背景下。该奖项由综合有机体系统部的生理机制和生物力学项目以及分子和细胞生物科学部的细胞动力学和功能组共同资助。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Ethylene and cytokinins are plant hormones that regulate many agronomically important traits, including fruit ripening, grain yield, shoot and root architecture, senescence, disease resistance, and drought resistance. Although these two hormones often antagonize the actions of each other, ethylene generally being considered a hormone that promotes aging of plant tissues while cytokinin promotes greening, these same two hormones sometimes act in a cooperative manner. The goal of this project is to uncover how these two hormones interact in the regulation of plant growth and development. A better understanding of plant hormone signaling will enable optimization of crops to improve their performance in various agricultural settings. The research project will provide excellent training opportunities for graduate students and postdoctoral fellows. In addition, through a local partnership, the project will establish a summer program aimed at developing education and science awareness through participatory activities that integrate science with art.This research project presents an integrated set of experiments to elucidate mechanisms of transcriptional crosstalk between the ethylene and cytokinin signaling pathways, building toward a systems level understanding of this process. The focus of the research is on the EIN3 and type-B ARR families of transcription factors that regulate the primary transcriptional responses to ethylene and cytokinin, respectively. The first objective is to characterize the role of combinatorial interactions between EIN3 and the type-B ARR transcription factors in the regulation of gene expression, initial results supporting both cooperative and antagonistic interactions. The second objective of this project is to characterize the role that physical interactions between EIN3 and the type-A ARRs, a family of negative regulators whose expression is strongly induced by cytokinin, play in modulating the activity of EIN3 and ethylene signaling. The third objective is to characterize the role that ethylene plays in activating the type-B ARRs independently of their activation by the cytokinin signaling pathway, this serving as an alternative pathway by which to regulate a subset of the ethylene responses. These studies will incorporate global analyses of gene expression and target binding by the transcription factors, using RNA-Seq and ChIP-Seq approaches. Models for interaction derived from these studies will be tested by mechanistic, transcriptomic, and genetic approaches, and placed within the context of the roles of ethylene and cytokinin in seedling growth.This award was co-funded by the Physiological Mechanisms and Biomechanics Program in the Division of Integrative Organismal Systems and the Cellular Dynamics and Function Cluster in the Division of Molecular and Cellular Biosciences.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.