NSF Postdoctoral Fellowship in Biology

This action funds an NSF Plant Genome Postdoctoral Research Fellowship in Biology for FY 2022. The fellowship supports a research and training plan in a host laboratory for the Fellow who also presents a plan to broaden participation in biology. The title of the research and training plan for this fellowship to Dr.

Kyle Swentowsky is “Developmental genetics and genomics of perennial regrowth in Zea diploperennis”. The host institution for the fellowship is Cold Spring Harbor Laboratory and the sponsoring scientist is Dr. David Jackson.

All plants are classified as either “annuals” that live for only one year or “perennials” that can live for many. Staple crops such as corn (maize), wheat, and rice are cultivated as annuals and are replanted from seed each year. Perennials, however, recycle their energy and nutrients for multiple growing seasons to achieve sustainable, long-term growth.

Compared to annuals, perennial plants tend to develop larger and deeper root systems during multiple years of growth, which allow them to access more water and nutrients in the soil. The development of perennial versions of existing crop species has the potential to combat challenges American farmers face due to climate change. Plant breeders have attempted to generate perennial maize lines but have so far been unsuccessful.

Careful analysis of the perennial life cycle has not yet been performed in grass species, and a detailed understanding of this biological process will greatly assist perennial breeding efforts. The goal of this project is to study how a perennial species closely related to maize achieves a perennial life cycle. This will include a description of how some plant organs can remain dormant during the initial growth cycle and become re-activated to achieve perenniality.

Discovering how some grass species maintain a perennial life cycle can help us develop perennial versions of existing cereal crops such as corn, wheat, rice, and sorghum that can be grown as sustainable options to combat the difficult growth conditions posed by climate change.

Perennial plants can regrow for multiple years and perennial crops are efficient sustainable agriculture systems. Some progress has been made in breeding perennial cereal crops but breeding perennial maize has been largely unsuccessful due to our poor understanding of genes and developmental mechanisms that control perenniality. Regrowth occurs in grasses when dormant axillary buds become active and although this general process has been well-studied in annual species, it is unclear how perennials coordinate regrowth with other life cycle events.

In this project, the close maize perennial relative, Zea diploperennis, will be used to investigate how phytohormone, sugar, flowering, and plant age signaling pathways impact perennial regrowth. This system will be used to test the hypothesis that: (1) the maintenance of Z. diploperennis tiller buds in a juvenile and non-flowering state is necessary for perennial regrowth; and (2) dormant tiller buds become reactivated through phytohormone or carbohydrate signaling after flowering to begin the next cycle of perennial growth.

Mechanisms of perennial regrowth will be studied using state of the art imaging, genetics, and single-cell RNA-sequencing techniques. Additionally, a previously identified QTL that controls regrowth will be fine-mapped to identify candidate perennial genes. All sequencing data will be deposited into the public NCBI Sequence Read Archive (SRA; https://www.ncbi.nlm.nih.gov/sra) and seeds generated during this project will be made publicly available via the Maize Genetics Cooperation Stock Center (http://maizecoop.cropsci.uiuc.edu/).

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.