Increasing advanced biofuels production from terpenes in Eucalyptus leaves

Principle Investigator: Gerald Tuskan
ORNL Co-investigators: Tim Tschaplinski, Hugh M. O'Neill, Sai Venkatesh Pingali


Terpenes have the highest energy density and affordable conversion efficiency of any biofeedstock. Research proposed here focuses on maximizing production, reducing volatilization and optimizing terpene content in Eucalyptus leaf oil glands (OG) for the creation of advanced fungible biofuel production in the U.S. By combining metabolic characterization, neutron scattering and transcript profiling, we will gain molecular-level insights into the determinant properties for synthesis and storage of terpenes in oil glands. Collectively, defining the genetic mechanisms of Eucalyptus leaf OG structure and chemistry will enable future applications of these resources for the genetic improvement of foliar OG number and volume, coupled with enhanced synthesis and storage of volatile and non-volatile terpenes. The scientific objectives are to identify individual Eucalyptus genotypes that have high potential for terpene production and to determine the genes that control biochemical and anatomical features of favorable terpene production.

BioEnergy Science Center: Focus Area 1 Biomass Formation

Director: Paul Gilna, ORNL
FA1 Lead: Debra Mohnen, University of Georgia
ORNL FA1 Co-investigators: Jay Chen, Udaya Kalluri, Wellington Muchero, Priya Ranjan, Tim Tschaplinski, Gerald Tuskan , Xiaohan Yang


The BioEnergy Science Center (BESC) is a multi-institutional (18 partner), multidisciplinary research (biological, chemical, physical and computational sciences, mathematics and engineering) organization focused on the fundamental understanding and elimination of biomass recalcitrance. BESC is one of three Bioenergy Research Centers established by DOE's Office of Science in 2007 to accelerate research toward the development of cost-effective advanced biofuels.

BESC's approach to improve accessibility to the sugars within biomass involves 1) designing plant cell walls for rapid deconstruction and 2) developing multitalented microbes for converting plant biomass into biofuels in a single step (consolidated bioprocessing). Addressing the roadblock of biomass recalcitrance will require a multiscale understanding of plant cell walls from biosynthesis to deconstruction pathways. This integrated understanding would generate models, theories and finally processes that will be used to understand and overcome biomass recalcitrance.

Project website:
For more information contact: Gerald Tuskan [back to top]

Engineering CAM Photosynthetic Machinery into Bioenergy Crops for Biofuels Production in Marginal Environments

Principal Investigator: John C. Cushman, University of Nevada, Reno
Co-investigators: Anne Borland, Jay Chen, James Hartwell, Madhavi Martin, Karen Schlauch, Tim Tschaplinski, Gerald Tuskan, David Weston, Xiaohan Yang


Crassulacean acid metabolism (CAM) is a photosynthetic CO2 fixation pathway that maximizes water use efficiency (WUE) many times relative to C3 species by using a temporal CO2 pump. Thus, CAM provides an excellent opportunity to engineer both enhanced photosynthetic performance and WUE into bioenergy crops. The proposed research will provide a comprehensive understanding of the enzymatic and regulatory pathways required to engineer CAM photosynthetic machinery into Populus. The methods employed will include deep transcriptome sequencing (RNA-Seq) and high-throughput metabolic profiling of leaf mesophyll cells and stomatal guard cells to identify regulators of the nocturnal opening and daytime closure of stomata that underpins the high WUE of CAM plants in order to create co-expression models. Additional deep genome sequencing combined with chromatin-immunoprecipitation (ChIP-Seq) experiments will be conducted to characterize the transcriptional regulatory networks needed for the circadian clock regulation of CAM. Once characterized, metabolic pathway components of 'carboxylation' and 'decarboxylation' modules will be assembled using an iterative cloning system, and CAM modules will be assembled singly and in combination into a predefined single locus of the target plant genome. Modules will be expressed under the control of circadian clock controlled, drought-inducible promoters in both the readily transformable model Arabidopsis and the important bioenergy crop Populus to promote maximal productivity. Resulting plants will be tested under both control and drought stress conditions for transgene expression, biochemical signatures of CAM, CO2 assimilation, stomatal conductance and transpiration rates, leaf carbon balance, level/mode of CAM activity, biomass productivity and quality, and integrated WUE.

Project website:
For more information contact: Xiaohan Yang [back to top]

A genome-enabled approach for predicting plant functional traits in dynamic vegetation models

Principal Investigator: David Weston
Co-investigators: Gerald Tuskan, Stan Wullschleger, Lianhong Gu, Jeffrey Warren, Priya Ranjan, Anthony Walker, and Wellington Muchero


Our inability to accurately represent plant functional traits (e.g., those traits governing photosynthesis) for a wide array of taxa and the interaction of those traits with variable environmental conditions are considered key uncertainties in land-surface models including the DOE BER funded Community Land Model (CLM). Given the importance of this issue, it is unfortunate that the scientific community is not currently leveraging advances in genomics and genetics to better predict plant traits that govern speciesí performance under various climatic conditions. Here, we will design a laboratory system and an instrumented field plot to: 1) develop advanced genomic modeling approaches to predict trait distributions for species critical to C cycling, 2) deploy this model as an open source service within the KBase knowledgebase project that is interfaced with climate models and, 3) test the output of model runs with laboratory and field based manipulations within a critical ecosystem. The proposed project will eliminate the current disconnection between BER genomics (BSSD) and Climate (CESD) based research, and thereby set the precedent where advances from biological system research are brought to bear in climate system research.

For more information contact: David Weston [back to top]

GTL-Foundational Science Plant-Microbe Interfaces Scientific Focus Area

Principal Investigator: Mitch Doktycz
ORNL Co-investigators (Plant): Jay Chen, Udaya Kalluri, Jessy Labbé, Wellington Muchero, Priya Ranjan, Tim Tschaplinski, Gerald Tuskan, David Weston, Xiaohan Yang


The Plant-Microbe Interfaces (PMI) project is a Scientific Focus Area directed towards understanding the dynamic interface that exists between plants, microbes and their environment. A specific focus is on defining the genetic bases of molecular communication between Populus and its microbial consortia. Understanding the inherent chemical and physical processes involved will facilitate natural routes to the cycling and sequestration of carbon in terrestrial environments, ecosystem response to climate change, and the development and management of renewable energy sources.

The project integrates expertise in the areas of plant genomics, fungal and bacterial research, fungal ecology, analytical tool development and computational biology and is based at the Oak Ridge National Laboratory, with collaborators at the University of Washington, Duke University, and INRA - Nancy (France). The project is a Foundational Genomics Scientific Focus Area supported by the Genomic Science Program of the Office of Biological and Environmental Research of the U.S. Department of Energy.

Project website:
For more information contact: Gerald Tuskan [back to top]

Strigolactones in the Woody Bioenergy Crop Populus

Principal Investigator: Jay Chen
Co-investigator: Tim Tschaplinski


An understanding of the signal transduction system associated with plant-environment interaction is critical for developing effective strategies for cost-effective, sustainable production of plant. Strigolactones (SLs) are a newly-discovered class of plant hormones controlling plant architecture, a key determinant of carbon sequestration, allocation and biomass production. More importantly, the synthesis of SLs in plants is regulated by the nutrient availability in soil and SLs serve as host recognition signals for symbiotic fungi. Therefore, SLs are viewed as integrative signaling molecules that couple nutrient availability and microbial symbiosis to the control of plant architecture. However, essentially nothing is known about this new class of plant hormones in the woody bioenergy crop Populus. In this project, we will use an integrative approach encompassing bioinformatics, metabolomics, physiology and microbiology to define SL pathways and decipher their role in plant-environment interactions driving plant architecture in Populus.

For more information contact: Jay Chen [back to top]