NSF Plant Genome Research Program
Project title: A Functional Genomics Approach to Investigate Regulation of Phenolic Glycoside Metabolism in Populus
Principal investigator: Chung-Jui Tsai (School of Forest Resources and Environmental Science)
Co-principal investigators:
Scott Harding (School of Forest Resources and Environmental Science)
Shuanglin Zhang (Department of Mathematical Sciences)
Mark F. Davis (National Renewable Energy Laboratory)
Project objectives: Functional characterization of pathways controlling salicylate-derived phenolic glycoside (PG) accumulation to understand PG homeostasis and its significance to woody plant growth and utilization.
Abstract: There is a wealth of evidence that the metabolic cost of defense is large in comparison to resources available for growth in plants. The abundant phenolic glycosides (PG) of Populus tree species are derived from salicylic acid, a metabolite that is central to the defense of herbaceous and woody plant species, but whose accumulation is extremely costly to herbaceous plant growth. By investigating the functional genomics of PG induction, biosynthesis and interconversion in a range of hybrid and transgenic Populus, we expect to learn how these plants accommodate such costly outlays, and to identify accountable genes of potential agricultural importance. Populus hybrids varying widely in leaf PG content and growth will be used to obtain differentially expressed PG-regulating and PG-sensitive genes. PG inductive treatments including nitrogen limitation and methyl-jasmonate application will be used to perturb PG homeostasis in the hybrids as well as in transgenically modified aspen, and to verify gene function and assess PG-growth interactions. EST sequences and microarray gene expression profiles derived from this work will be deposited in GenBank and accessible at aspenDB. cDNA microarrays will also be made available to the research community.
Experimental Approaches:
1. EST: Collection of non-redundant ESTs from highly PG-active Populus tissues.
2. Microarray profiling: Expression analysis and stress treatments to identify genes related to PG biosynthesis and turnover.
3. Metabolic profiling: Chemical fingerprinting and metabolite analysis to identify markers of experimentally-induced perturbations in PG metabolism.
4. Transgenic manipulation: Generation of aspen knockout lines to test gene effects on PG homeostasis.
5. Bioinformatics: Integration of EST, microarray and metabolic data in a relational database.
6. Outreach: Summer Youth Programs (minority high school students); Family Science Nights (local elementary students); Professional Microarray Workshop (tree physiologists and ecophysiologists).
Broader Impact: PGs are one of three major phenylpropanoid sinks affecting biomass and biofuels production as well as carbon sequestration in fast-growing tree species of the taxa Salicaceae (poplar, willow) and Betulaceae (birch). PGs, along with phenylpropanoid product condensed-tannins and lignins, comprise 20-60% of leaf dry weight and are abundant in stem and root tissue as well. Leaf phenylpropanoid content correlates negatively with tree biomass, and may be an important determinant of tree productivity. How growth and other value-added traits are affected by metabolic partitioning among the phenylpropanoids is not clear. The pathway steps leading to condensed tannin and lignin synthesis have been identified while those leading to PGs have not. By elucidating some of the steps controlling synthesis and utilization of salicylic acid for PG synthesis, we expect to move closer to understanding control of phenylpropanoid composition. This should improve the efficiency with which trees are managed, not only for their harvestable biomass, but also for their impact on habitat productivity, and their value in novel applications such as the long-term storage of atmospheric carbon in the form of stable phenylpropanoid products.
Collaborators:
Professor Huann-Sheng Chen (Department of Mathematical Sciences, MTU)
Professor Rick Lindroth (Department of Entomology, University of Wisconsin, Madison)
Professor Tom Whitham (Department of Biological Sciences, Northern Arizona University)
Project Personnel:
Abdur Sikder (Bioinformatics Postdoc)
Yinan Yuan (Postdoc)
Benjamin A. Babst (postdoc)
Raja Payyavula (PhD student, Forest Molecular Genetics and Biotechnology)
Jingwei Yin (PhD student, Forest Molecular Genetics and Biotechnology)
Huaizhen Qin (PhD student, Mathematics)
Robert Sykes (Research scientist, NREL)
Sandy Hubscher (Technician)
Michelle Jarvie (Technician)
Stephanie Drake (Undergraduate assistant, SURF 2006)
Emily Umlor (Undergraduate assistant)
Idaliza Gomez (Undergraduate assistant, REU 2006)
Mehreteab Mengsteab (Undergraduate assistant, REU 2006)
Past project personnel
Han-Wei Lin (Postdoc)
Kurt Doran (Undergraduate assistant)
Scott Elliott (Undergraduate assistant, bioinformatics)
Elizabeth Fraki (Undergraduate assistant)
Erin Haglund (Undergraduate assistant)
John Montag (Undergraduate assistant)
Flor Ramirez (Undergraduate assistant)
Blast Search
ESTDB
ArrayDB
MPDB
qPCR Schedule
Project Personnel
NSF Project
DOE Project
Outreach
Download
Summer Youth
|
|
|
AspenDB is supported by National Science Foundation (NSF) Department of Energy (DOE) Michigan Life Science Corridor (MLSC) |