Characterization of novel regulators of the ethylene biosynthesis pathway in Arabidopsis.

The volatile plant hormone ethylene is vital for many biological processes, and the precise control of ethylene synthesis is critical for plant health and crop production. Our research proposal will characterize novel regulators of the ethylene biosynthesis pathway in Arabidopsis. Ethylene is produced by a relatively simple pathway, in which the general precursor 1-aminocyclopropane-1-carboxylic acid (ACC) is eventually converted to ethylene by ACC-oxidase (ACO), the ethylene-forming enzyme. Both the level of ACC and the activity of ACO hold key positions in this pathway. Little is known about the players that influence ACC homeostasis, despite novel reports that ACC can signal in plants independently from ethylene. Furthermore, it has been reported that ACO can be rate limiting in ethylene production, yet the transcriptional/post-translational regulation of ACO remains largely unexplored. In order to find novel regulators of ACC homeostasis and ethylene production, the Van de Poel lab has conducted a novel EMS mutagenesis screen and performed a GWAS screen for ethylene production. In this proposal, we will further investigate these candidate regulators (mutants and target genes), and unravel their mode of action and their specific mechanistic function in Arabidopsis using revere genetics and biochemical/molecular assays. These discoveries will lead to novel fundamental insights in how plants regulate their ACC pool and control their ethylene production level.