PhD Student University of California San Diego San Diego, California
Body of Abstract: My lab applies Desorption Electrospray Ionization Mass Spectrometry Imaging (DESI-MSI) to map small molecule localization patterns across maize root meristems. We have found that these small molecule localization patterns can inform predictions of small molecule functions in development. For example, we found that succinate, a compound enriched in the stem cell niche (SCN), promotes stem cell divisions. Our DESI-MSI studies have identified dozens of molecular signatures localized to the maize root SCN. My central research objective is to chemically identify molecular signatures concentrated in the SCN and to understand their function. To elucidate structures of SCN enriched molecules, I deploy Electrospray Ionization Tandem Mass Spectrometry (ESI-MS/MS) on maize root samples. Using this approach, I have identified molecular signatures with strong localization to the SCN, including those that correspond to a series of benzoxazinoids (BXs). BXs have been studied extensively for their role in biochemical defense against a variety of biotic stresses. However, the strong enrichment of BXs to the maize root SCN raises an interesting question: do BXs play a role in maize root development? My work aims to characterize the developmental function of BXs by phenotyping maize root response to exogenous treatments and genetic perturbations. Preliminary results suggest that a BX compound can promote certain aspects of root growth, suggesting that BXs may be more than just defense compounds. I am continuing to investigate the role of BXs in maize development through 1) phenotypic analysis of BX deficient mutants and 2) transcriptomic analysis. Results of this study will further elucidate if BX genes have a role beyond defense and are regulators of maize stem cell decisions. Investigation into core principles governing small-molecule control of maize development could strengthen quantitative strategies for enhancing crop vigor under a variety of stressors.