Poplar esterified cell wall transformations and metabolic integration (PECTIN) study
EMSL Project ID
50708
Abstract
Polysaccharides are major components of plant cell walls that can be converted into fuels by microbial fermentation, making plant biomass an important bioenergy resource. However, a substantial fraction of plant cell wall polysaccharides are chemically modified with methyl and acetyl groups that can reduce fermentation yields. Although little is known about the biochemical and physiological functions of those cell wall modifications in trees, recent evidence in Arabidopsis suggests that they are critical for proper development and functioning of xylem vessels1 and leaf stomata2. While generally considered a waste product of cell wall physiochemical changes, we recently demonstrated that plant-atmosphere emissions of the volatile intermediates methanol and acetic acid are tightly associated with tree growth, stress, and senescence processes and can be both emitted to the atmosphere via stomata and integrated into central C1 and C2 plant metabolism3. However, methanol and acetic acid are not captured by traditional metabolomics analysis, representing an important gap in our knowledge of cell wall metabolism and its interactions with the environment. To address these knowledge gaps, a DOE BER early career research project (ECRP) was recently funded entitled, “O-Acetylation and methylation engineering of plant cell walls for enhanced biofuel production”. This 5-year project started Nov 1st, 2018 (PI: Dr. Kolby Jardine) will study the metabolism of those cell wall modifications and volatile intermediates as well as their role in central physiological processes in the emerging biofuel tree species California poplar (Populus trichocarpa) using field settings and controlled environmental conditions.Specific Aims
Our goal at EMSL is to launch this collaborative and interdisciplinary ECRP project by leveraging cutting-edge EMSL instrumentation and technical collaborations. The main goal of this project is to quantify O-acetyl and methyl ester cell wall metabolism in poplar and its interactions with central metabolism and volatile metabolite exchange with the atmosphere. Critical to this goal is the development of novel methodology for xylem injections of 13C- metabolite solutions involved in cell wall ester metabolism with injection flow rates scaled to sap flow. Using detached leaves to simulate drought and initiate senescence, a secondary goal is to determine quantitative relationships between the emissions of leaf methanol and acetic acid and changes in the degree of cell wall acetylation and methylation. These goals will be achieved by leveraging expertise in plant physiological and hydraulic methodologies, including volatile metabolomics and novel stable isotope techniques, led by the PI gained through DOE funded programs in the tropics (GoAmazon and NGEE Tropics) with EMSL user facility research infrastructure and expertise including growth chambers, metabolomics analytics, real-time leaf/atmosphere volatile emissions, and research expertise on plant 13C-labeling and cell wall chemical analysis. A postdoc will be contracted through the ECRP project to help lead the research with the PI and engage the Co-PIs with expertise in cell wall metabolism (Dr. Jenny Mortimer, LBNL), structure and function of plant carbohydrate active enzymes (Dr. Breeanna Urbanowicz, University of Georgia), and poplar quantitative genomics (Dr. Wellington Muchero, ORNL). By working closely Dr. Nancy Washton at EMSL on solution/gel state 2D-NMR chemical analysis of whole-plant cell walls, we will engage EMSL staff and collaborators with expertise in non-structural carbohydrates and plant response to drought (Dr. Nate McDowell, PNNL/EMSL), stable carbon isotope methods in mass spectrometry and plant metabolism (Dr. Mary S. Lipton and Albert Rivas, EMSL), and volatile organic compound emissions from plants (Dr. Alex Guenther, UCI/EMSL).
Project Details
Start Date
2019-04-29
End Date
2019-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)
Team Members