ing out chloroplasts, which contain chlorophyll, the molecule that absorbs energy from sunlight, giving plants their green color and capturing carbon dioxide through photosynthesis.
Instead, their work revealed something unexpected: the additional section of the enzyme allowed the enzyme to enter the nucleus, which is the plant cell’s brain center, and “moonlight” as a DNA-binding regulator of gene expression.
Discovering the direct connection opens new opportunities to tweak how lignin is produced in poplar without impacting other biological processes that could kill the plant.
“This enzyme’s unique behavior contrasts with conventional wisdom in the plant community,” Muchero said. “While we do not know how this new function came about in poplar, we now know that this enzyme exhibits the same behavior in other plant species.”
The new insights will help support ORNL industry partners GreenWood Resources and Forage Genetics International who have licensed the poplar gene technology for separate applications, but each with the common goal of breeding plants with modified lignin content.
“This discovery has enabled the new Center for Bioenergy Innovation to rationally design plants with either increased or decreased lignin,” said Jerry Tuskan, CBI director at ORNL.
“Modified lignin in plants can lead to valorization of lignin and displacement of petroleum as a precursor for plastics,” he added. “One day, drinking bottles or plastic toys may come from poplar plants.”
The team published their findings in The Plant Cell journal. Coauthors of the paper titled, “A 5-enolpyruvylshikimate 3-phosphate synthase functions as a transcriptional repressor in Populus,” included ORNL’s Meng Xie, Wellington Muchero, Anthony C. Bryan, Kelsey Yee, Timothy J. Tschaplinski, Raja S. Payyavula, Nancy Engle, Sara S. Jawdy, Lee E. Gunter, Olivia Thompson, Udaya Kalluri, Miguel Rodriguez, Kai Feng, Jin-Gui Chen and Gerald A. Tuskan.
Additional coauthors were from the University of Tennessee, Knoxville; the DOE Joint Genome Institute, the University of North Texas, the National Renewable Energy Laboratory, West Virginia University, ArborGen Inc. and HudsonAlpha Institute.