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.
