image: Purdue researcher Nick Carpita said plants may be able to produce more biofuel mass if the means of shutting down cellulose production is disrupted. His research team learned that small RNAs are key in determining the duration of cellulose production. view more
Credit: Purdue Agricultural Communication photo/Tom Campbell
WEST LAFAYETTE, Ind. - Purdue University researchers found a mechanism that naturally shuts down cellulose production in plants, and learning how to keep that switch turned on may be key to enhancing biomass production for plant-based biofuels.
Nicholas Carpita, a professor of botany and plant pathology, said that small-interfering RNAs (siRNAs) play a normal role in plant development by shutting off genes involved in primary cell wall growth in order to begin development of thicker, secondary cell walls.
"These small RNAs were known to play a role in fending off disease-causing pathogens, but we are only now beginning to understand their involvement in normal plant development," he said.
Carpita's research team reported its findings in Monday's (Dec. 15) early online issue of the Proceedings of the National Academy of Sciences.
"If we can learn to interfere with the down-regulation of cellulose synthesis, then plants may be able to produce more cellulose, which is key to biofuels production," Carpita said.
Mick Held, a postdoctoral researcher in Carpita's lab, virologist Steve Scofield, a U.S. Department of Agriculture research scientist and adjunct assistant professor of agronomy at Purdue, and Carpita made the discovery in barley after introducing a virus as a way to "silence" specific genes and study their functions. The researchers noticed that the virus had more effect then anticipated.
"The virus hijacked a whole suite of genes, and when we compared the targeted plant to our control plants we found that the small RNAs were responsible and already in the controls even without adding the virus," Held said.
Carpita said this let researchers see that the siRNAs - among other things - regulate and shut down primary cell wall development to begin secondary wall growth.
"These secondary stages result in characteristics such as tough rinds of corn stalks, vascular elements to conduct water and fibers for strength," he said.
The researchers said that delaying or preventing the shutdown of both primary and secondary cellulose production might enhance total plant biomass.
"Most biofuel researchers believe that cellulose utilization offers the best path to sustainable ethanol production," Scofield said. "Our work uncovered a previously unknown mechanism that suggests a way to increase the amount of cellulose produced in plants."
Other members of the research team were Bryan Penning and Sarah Kessans of Purdue and Amanda Brandt of the USDA/Ag Research Service, Crop Production and Pest Control Research Unit located at Purdue.
The research was funded by a U.S. Department of Energy, Energy Biosciences grant.
Writer: Beth Forbes, (765) 494-2722, forbes@purdue.edu
Source: Nicholas Carpita, (765) 494-4653, carpita@purdue.edu
Mick Held, heldm@msu.edu
Steve Scofield, Office: (765) 494-3674; Lab: (765) 496-2232, scofield@purdue.edu
A publication-quality photo is available at http://news.uns.purdue.edu/images/+2008/biofuel-corn-stalks.jpg
Abstract on the research in this release is available at: http://news.uns.purdue.edu/x/2008b/081217CarpitaRNA.html
Purdue University
News Service
400 Centennial Mall Drive, Rm. 324
West Lafayette, IN 47907-2016
Voice: 765-494-2096
FAX: 765-494-0401
STORY AND PHOTO CAN BE FOUND AT: http://news.uns.purdue.edu/x/2008b/081217CarpitaRNA.html
Note to Journalists: A copy of the research paper is available at http://www.pnas.org/cgi/doi/10.1073/pnas.0809408105 or by contacting the PNAS news office at (202) 334-1310, PNASNews@nas.edu
Journal
Proceedings of the National Academy of Sciences