Projects

  • In collaboration with Dr. Justin Walley (PLPM), we have recently characterized a large-scale catalog of ubiquitinated proteins from Arabidopsis roots using diGly affinity purification followed by mass spectrometry. 

  • Auxin regulated gene expression has been extensively studied and is known to involve active transcriptional regulation as well as protein degradation. One outstanding question in the field is how these gene expression changes are captured at the level of protein abundance. In order to address this knowledge gap, we have utilized global proteomics profiling approaches across tissues and time in Arabidopsis following auxin treatments. Using young 5 day-old seedlings we treated intact plants with a naturally occurring auxin, indole-3-acetic acid, for 30 min - 3 hours and then harvested tissue for profiling such that we were able to capture changes in protein abundance in seedlings, roots and hypocotyls.

  • Myosins are evolutionarily conserved motor proteins that carry out a myriad of cellular functions. Using quantitative proteomics (Kelley et al., bioRxiv 2017) and reverse genetics, we identified an auxin-regulated Class VIII myosin, ATM1, that is required for hypocotyl elongation (Olatunji & Kelley 2020) and root growth (Olatunji et al., bioRxiv 2022). ATM1 is a plasmodesmal protein that is required for sugar-dependent growth in both shoots and roots. We are currently investigating the molecular function of ATM1 using genetics, live-cell microscopy, and proteomic approaches.

     

  • Auxin signaling is a key regulator of root morphogenesis in angiosperms, yet this pathway is understudied in maize and little is known regarding genetic factors that determine maize root architecture. Recent reports have demonstrated that root architecture can directly impact yield and drought resistance in maize. The overall objective of this project is to understand the key regulatory events governing auxin-mediated root development in maize using an integrated molecular genomics-to-phenotype approach. Specifically, we will (1) define roles for ZmARF27 in early root development (2) uncover functions of ZmPILS2 and ZmPILS6 (also called ZmPINY and ZmPIN14) in promoting maize root morphogenesis and (3) determine predictive multi-scale auxin responsive regulatory networks that underpin maize root architecture.

  • GAUT10 is an enzyme required for pectin biosynthesis with established roles in root growth (Pu et al., 2019) and stomatal development (Guo et al., 2021). We are investigating how GAUT10 influences auxin homestasis, cell elongation, and cell division during root morphogenesis using genetics, live-cell microscopy, and biochemical approaches (Dash et al., bioRxiv 2023) in collaboration with Olga Zabotina. We are also studying protein properties of GAUT10 to determine how it is regulated by auxin posttranscriptionally (Pu et al., 2019) and how it contributes to cell wall dynamics.