Speaker: Paula McSteen, University of Missouri professor of biological sciences

Title: "Auxin and vesicle trafficking in maize reproductive development"

Abstract: The plant growth hormone, auxin, is required for a myriad of processes in plant development and response to biotic and abiotic stress.  Localized auxin biosynthesis, transport and signaling work together to create maxima of auxin (with adjacent minima) where organ formation occurs.  Key to the regulation of the direction of auxin flow is the polar localization of PINFORMED (PIN) proteins in the plasma membrane. Therefore, PIN protein localization is highly regulated by multiple mechanisms including constitutive endocytosis, vesicle trafficking and phosphorylation. Using forward and reverse genetics, we have identified mutations in multiple components of the vesicle trafficking machinery in maize with defects in auxin transport, that we hypothesize function in regulation of ZmPIN1a proteins.

Maize has separate male and female reproductive structures (tassel and ear). Mutants defective in auxin biosynthesis, transport and signaling cause a reduction in the number of branches and spikelets (the short branches that make flowers) in the tassel and the number of kernels in the ear due to the failure of auxin maxima to be formed (or responded to).  Therefore, auxin plays a critical role in organogenesis in maize development with direct impacts on yield.  I will present our research on the role of two recently identified genes in regulating auxin transport in maize reproductive development. 

Short biography: Paula McSteen is a developmental geneticist studying the role of the plant growth hormone, auxin, in maize reproductive development. She did her Ph.D. on flower development in Antirrhinum (snapdragon) with Enrico Coen at the John Innes Center, Norwich, United Kingdom, and a postdoc on maize inflorescence development with Sarah Hake, at the Plant Gene Expression Center/University of California, Berkeley. She was an assistant and associate professor at Pennsylvania State University (2002-2010) and associate and full professor at the University of Missouri-Columbia (2010-present). She was elected a Fellow of the American Association for the Advancement of Science in 2020 and received the L. Stadler Mid-Career Excellence in Maize Genetics Award in 2017.

Host: Dior Kelley, genetics, development and cell biology assistant professor