Dior Kelly, Department of Genetics, Development, and Cell Biology, ISU

Abstract: Regulation of root growth and development is controlled by hormones such as auxin. Some outstanding questions in the field are (1) what auxin pathways underpin maize root morphogenesis and (2) how does auxin-dependent posttranscriptional gene expression impact root development? It has been proposed that reduced root development and/or altered root architecture would be advantageous for drought resistance and increased yield in maize. A major challenge in the field is identification of key regulators of various maize root types. Using reverse genetics, we have recently identified three novel loss of function auxin pathway maize mutants with altered root phenotypes that are linked to auxin responses. Additionally, we have recently generated a comprehensive site-level ubiquitinome profiles for Arabidopsis roots that furthers our understanding of the biological processes mediated by this posttranslational modification (PTM) in plants. To characterize the biological function imparted by a given PTM in plants, at specific amino acid residues, we currently rely on creating transgenic lines encoding PTM null or mimic mutations with wild-type controls. We are developing a method for precise base editing in maize based on published studies that will be deployed to test the functional significance of protein PTMs for key proteins of interest. Collectively these studies will improve genome editing tools for maize and generate novel germplasm that can both expand trait evaluation and facilitate gene discovery.