Ethylene Signal Transduction: Proteomics and Molecular Mechanisms

University Of Maryland, College Park, College Park MD

Investigators

Abstract

Intellectual merit. Ethylene is a gaseous plant hormone that has profound effects on numerous aspects of plant growth and development, including adaptive responses to a wide range of biotic and abiotic stresses. The current framework of the ethylene signal transduction pathway starts with ethylene perception and leads to changes in gene expression. Much of what is known about the ethylene signaling pathway is based on genetic dissection in the reference plant Arabidopsis thaliana. While great progress has been made in identifying key players in the signaling pathway, the molecular mechanisms by which these proteins signal remain largely unknown. A limitation is that genetic screens cannot directly detect hormone-induced changes in protein level, activity, localization or function, which form the basis of signal transduction. In addition, a number of components may be recalcitrant to genetic dissection. This project has two objectives. The first is to attain new levels of understanding of ethylene signal transduction using proteomic methods to identify previously unknown ethylene signaling components and their molecular mechanisms. These methods will identify proteins that are rapidly modified in response to ethylene, as well as proteins that physically interact in the pathway. Protein modification and protein-protein interactions are essential to the mechanisms of intracellular signal transduction, but have been relatively unexplored in ethylene signaling. The second objective is to carry out analyses of mutants and genes that are currently in hand, with a particular focus on a gene called RTE1, which regulates signaling by the ETR1 ethylene receptor. RTE1 is a novel membrane protein conserved in plants, animals and some protists. The cellular role of RTE1 and how RTE1 specifically regulates ETR1 signaling will be investigated through a combination of molecular genetics, cell biology and biochemistry approaches. The extensive molecular genetic tools that exist for ethylene signaling, coupled with the availability of powerful proteomic methods, provide an exceptional opportunity to advance our knowledge of ethylene signal transduction. Broader impacts. This project provides research training and mentoring of undergraduates, graduate students, and a postdoctoral researcher, who are typically from underrepresented groups. Laboratory members will present their research at a variety of scientific meetings, both local and international, and will participate in teaching outreach. The postdoctoral researcher will follow a career development plan supported by research training in the laboratory, student mentoring experiences and professional development seminars and workshops. Given the fundamental importance of ethylene in plant growth and development, the mechanistic insights provided by the proposed studies could have an impact on enhancing agricultural products for human nutrition and plant biomass optimization.