| NSF Org: |
IOS Division Of Integrative Organismal Systems |
| Recipient: |
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| Initial Amendment Date: | July 24, 2018 |
| Latest Amendment Date: | July 24, 2018 |
| Award Number: | 1812235 |
| Award Instrument: | Fellowship Award |
| Program Manager: |
Diane Jofuku Okamuro
dokamuro@nsf.gov (703)292-4508 IOS Division Of Integrative Organismal Systems BIO Direct For Biological Sciences |
| Start Date: | August 1, 2018 |
| End Date: | July 31, 2021 (Estimated) |
| Total Intended Award Amount: | $216,000.00 |
| Total Awarded Amount to Date: | $216,000.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
St. Louis MO US 63132-2918 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
St. Louis MO US 63132-2918 |
| Primary Place of Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | NPGI PostDoc Rsrch Fellowship |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.074 |
ABSTRACT
This action funds an NSF National Plant Genome Initiative Postdoctoral Research Fellowship in Biology for FY 2018. 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. Jennifer Arp is "Engineering Optimized Source-Sink Interaction in Maize and Sorghum." The host institution for the fellowship is the Donald Danforth Plant Science Center and the sponsoring scientist is Dr. Douglas Allen.
As the world population increases, crop breeding efforts will need to increase yields while minimizing detrimental impacts on the environment. In particular, understanding how plants acquire and use nitrogen can help determine proper fertilizer use. Plant nitrogen demands vary in different parts of the plant based on whether the tissue is photosynthetic and acting as a source of carbon, as in leaves, or is a sink for carbon and nitrogen as in seeds. Plants with optimized source-sink relationships could break the inverse correlation between yield and protein content that is well-documented over the last 50 years. Training objectives for the Fellow include synthetic biology, genetic engineering, and metabolic flux analysis. Broader impacts include promoting plant science through outreach programs with the St. Louis Girl Scouts, ASPB Planting Science, and Future Trek STEM Careers.
This project will use a genetic approach in maize, sorghum, and the C4 model species Setaria viridis to investigate the interrelationship between asparagine cycling in nitrogen metabolism and the C4 photosynthetic pathway in leaves and seeds of cereals in order to modulate source and sink relationships. New expression patterns for genes involved in asparagine cycling and C4 photosynthesis will be engineered to optimize expression throughout the plant life cycle and break the protein and yield tradeoff. Results from this research will be disseminated at conferences and through publications. Data generated will be submitted to data repositories: Panzea (http://www.panzea.org), NCBI-SRA (http://www.ncbi.nlm.nih.gov/sra), NCBI-GEO (http://www.ncbi.nlm.nih.gov/geo), and Maize Genetics and Genomics Database (http://www.maizegdb.org).
Keywords: Maize, Setaria, Sorghum, Nitrogen, Photosynthesis, Source-sink
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.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Jennifer Arp has completed research for her postdoctoral fellowship titled “Engineering Optimized Source-Sink Interaction in Maize and Sorghum” supported by the NSF PGRP PRFB. During her funding period, she spent three years at the Donald Danforth Plant Science Center in Saint Louis, MO. As a plant functional genomicist, Jennifer is interested in testing gene function specifically related to the interaction of nitrogen use efficiency and photosynthesis. The goal of this project was to investigate the interrelationship between asparagine cycling and the C4 photosynthetic pathway in leaves and seeds of cereals in order to modulate source and sink relationships; such improvements would be valuable for breaking the protein and yield tradeoff.
During this project, new genetic materials were developed. These include transposon insertion mutant lines in maize for six genes involved in the C4 photosynthetic pathway and homozygous double mutants between many of the mutant lines. In addition, four genes involved in C4 photosynthesis were targeted for CRISPR-Cas9 gene editing in the model C4 plant Setaria viridis, which returned editing events in three genes. Another goal of the project was to characterize differences in C4 photosynthetic pathways in maize. In one experiment, plants were grown in the greenhouse in ten-day intervals to measure plants at different growth stages simultaneously. The two C4 pathways in maize were compared using gene expression, enzyme activity, and stable isotope labeling. Overall plant age did not impact the ratio of the two pathways, but the leaf position in the canopy was correlated with increased NADP-malic enzyme pathway compared to phosphoenolpyruvate carboxykinase (PEPCK) pathway flux. C4 pathways were also characterized using mutants in the PEPCK1 gene which had been previously developed. Mutant maize lines were grown under different nitrogen treatments in the field to characterize the interaction of C4 pathways and nitrogen use. Overall plants with decreased PEPCK pathway activity were better able to apportion their biomass to grain compared to leaves and stems at maturity under both low and high nitrogen treatments.
The broader impacts of the fellowship award include the training of PI Arp in broader research skills which include synthetic biology, genetic engineering, and biochemistry, which have enabled her to become established as an independent scientist. In addition, four undergraduate researchers were trained in molecular biology skills during year 1 of the project (before the COVID-19 pandemic) to enable students to perform a transposon-based mutant screen.
Last Modified: 11/24/2021
Modified by: Jennifer J Arp
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