NSF Postdoctoral Fellowship in Biology FY 2020

Oravec, Madeline W., Saint Paul MN

Investigators

Abstract

This action funds an NSF Plant Genome Postdoctoral Research Fellowship in Biology for FY 2021. 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. Madeline Oravec is "Evaluation and Exploitation of Temporally-Regulated Hormone Signaling for Enhanced Cold Tolerance in Brassica rapa." The host institution for the fellowship is the University of Minnesota and the sponsoring scientist is Dr. Kathleen Greenham. Cold temperatures limit geographical range and seasonal yield of crop production. Development of cold tolerant crops is therefore a consistent goal of plant breeding and genetic engineering efforts. Plant productivity is dependent on a balance between stress response and growth. One way that plants achieve this is through time-of-day specific hormone signaling and gene expression. Brassica rapa is a diverse crop species, encompassing a wide variety of crops, including sarson (mustard seed), Chinese cabbage, bok choy, turnip, leafy vegetables, and oilseed. This project uses multiple approaches to investigate how differences in cold tolerance across B. rapa varieties are related to time-of-day specific gene expression, hormone signaling, and physiological response to cold. This research aims to directly enhance the cold tolerance of cold-sensitive B. rapa varieties. Findings from this work will provide insights into time-of-day variation in hormone signaling and stress response in plants, and the approach will be widely applicable to improvement of other crops. Training objectives include obtaining skills in transcriptomics, physiology, and synthetic biology, as well as in independent research, science communication, and mentorship. The broader impacts of this project include teaching plant biology modules in minority-serving K-12 schools, direct mentorship of high school, undergraduate, and graduate students, and community outreach at local events through participation in the Market Science program. Plants coordinate and balance stress response and productivity through circadian and diel regulation of gene expression and hormone signaling. Brassinosteroids are phytohormones that regulate cold stress response and exhibit diel fluctuations. Temporal modification of brassinosteroid signaling could therefore improve cold tolerance without compensating growth and yield. The specific research objectives of this project are to (1) evaluate temporal gene expression patterns of cold responsive brassinosteroid-related genes across diverse cold tolerant and sensitive B. rapa morphotypes, (2) assess changes in cold response and tolerance in B. rapa with varied time-of-day applications of exogenous brassinosteroid, and (3) alter temporal expression of brassinosteroid-responsive transcription factors in B. rapa to enhance cold tolerance. Through interdisciplinary approaches, including transcriptomic analyses, physiological assays, and genetic engineering, this work will leverage pan-genome data and within species variation to evaluate and exploit temporal regulation of brassinosteroid signaling to enhance cold tolerance in B. rapa. This research will advance scientific knowledge of temporal gene regulation and diel hormone signaling in relation to cold stress response. The methods developed will inform future research, breeding, and genetic engineering efforts to manipulate temporal stress response to develop more resilient and stress tolerant crops while maintaining growth and productivity. All scripts will be curated on the Greenham lab Github site (https://github.com/GreenhamLab), generated data will be provided in publications and/or through CyVerse (https://www.cyverse.org/), and synthetic constructs and transgenic lines will be submitted to and made available through the Arabidopsis Biological Resource Center (ABRC). 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.