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 long-term 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.
From a reverse genetic screen based on auxin pathway proteins enriched in maize primary roots, we identified the Class A Auxin Response Factor (ARF) ZmARF27 as a positive regulator of primary root length, root hair formation, and auxin mediated gene expression (Dash et. al., 2023 bioRxiv).
We also identified the PIN-LIKES auxin transporter, ZmPILS6, as a key regulator of organ size control (Cowling et. al., 2024, cover article). PILS transporters are ancient among algae and land plants, but their roles in cereal crops are not well understood. We found that a reduction in PILS6 levels in corn leads to smaller root systems, shorter stature corn, and altered hormone pathway protein abundance. These findings have the potential to influence plant breeding strategies by improving the maize germplasm genetics.
Using omics approaches we have characterized auxin responsive gene regulatory networks in maize roots (McReynolds et al., 2022) and uncovered links between gene expression patterns and root system architecture (Callwood et al., 2024 bioRxiv, accepted at Plant Phenomics).
Our studies on auxin mediated root development in maize have necessitated the development of standardized protocols for exogenous hormone treatments on maize seedlings (Draves and Muench et al., 2022, cover article; Gonzales et al., 2024) to enable high throughput phenotyping (Callwood et al., 2024 bioRxiv, accepted at Plant Phenomics).
These projects were initially funded by USDA NIFA AFRI through their Physiology of Agricultural Plants and Workforce Development programs. Continuing support for these studies is via the Crop Bioengineering Center and Plant Sciences Institute.
Funding Organization: USDA AFRI NIFA
Duration: 12/21/2020 to 05/31/2024
Award Amount: $450,000.00
Award Number: IOW05613
Principal Investigator(s): Dr. Dior Kelley (PD), Dr. Justin Walley (Co-PD)