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Two U of I plant researchers studying Miscanthus and sorghum as bioenergy crops awarded funding as part of larger clean energy program

Published October 27, 2014
Miscanthus x giganteous. Photo by Brian Stauffer, University of Illinois.

URBANA, Ill. – Two University of Illinois crop sciences researchers interested in improving plant feedstocks for bioenergy production were selected to receive funding by the U.S. Department of Agriculture (USDA) and the U.S. Department of Energy (DOE) as part of a larger Obama administration effort to diversify the nation’s energy portfolio and accelerate development of new clean energy.

Erik Sacks and Pat Brown, both assistant professors in plant breeding and genetics in the College of ACES, each are leading two of 10 projects from around the country that were awarded the funding aimed at accelerating genetic breeding programs to improve plant feedstocks for the production of biofuels, biopower, and biobased products.

The $12.6 million in research grants was awarded earlier this year under a joint DOE-USDA program that began in 2006 focused on fundamental investigations of biomass genomics, with the aim of harnessing nonfood plant biomass for the production of fuels such as ethanol or renewable chemical feedstocks. 

Sacks and his team, including U of I professor of plant biology and crop sciences Steve Long, were awarded ~$1.5 million to continue working on breeding efficiency of the perennial grass crop Miscanthus x giganteous (Mxg), which has become an important feedstock crop in the emerging bioenergy industry. Mxg is high yielding, needs few inputs, and adapts well to temperate climates. But with limited diversity in the crop, researchers know the survival of Mxg over time is at risk.

“There are a lot of named cultivars or varieties of Miscanthus, but when we looked at their molecular markers, we saw that essentially they’re all the same,” Sacks said. “This isn’t a good situation for establishing any new crop, really, to have that little genetic diversity because if you start planting a monoculture of one clone over a wide area, eventually a pest could take everything down all at once. We learned this lesson in the past with reduced genetic diversity in the maize crop. We don’t want to repeat that mistake with Miscanthus.”

Sacks’s research is providing new information on the evolution and genetic makeup of the plant that could lead to improvement and greater security of the crop in the future. The researchers are now looking at hundreds of accessions of one parental species of the Mxg crop, M. sacchariflorus (Msa), from its natural range in China, Japan, Korea, and Russia. Through DNA sequencing, they will obtain thousands of genetic markers in order to determine population structure. The researchers will then use field trials at multiple locations to evaluate yield potential and adaptation.

By combining the DNA sequencing information and field data they will be able to associate traits of interest with molecular markers, which can be used to improve breeding efficiency and allow plant breeders to quickly develop improved biomass cultivars of Mxg. A previous study conducted by Sacks has helped to trace the genetic diversity and population structure of the other parental species of Mxg, M. sinensis (Msi), providing new information for breeding and improvement of Mxg as a bioenergy crop.

“This study is the next logical step because the Miscanthus species used for bioenergy primarily is a cross between sacchariflorus and sinensis,” Sacks explained. “The logic here is that we need to understand something about both parental species in terms of genetic diversity and population structure and have access to germplasm to understand the traits and use molecular markers to improve breeding efficiency. We know about the structure of sinensis but sacchariflorus is a black box to us. We only know a little about it, and it may be more complicated than sinensis.”

Because Miscanthus can be crossed with sugarcane, this project will also provide materials and data that could help in the development of more cold-hardy sugarcanes and energycanes.

Brown was awarded $1.3 million in funding from the program for his ongoing work with biomass sorghum. Brown will be working with 600 lines of sorghum and looking for natural variation in composition that could be useful for breeding biomass sorghum.

“We are looking for classic traits such as low lignin,” Brown said. “Lines with low lignin tend to fall down easily—to lodge—which is a trade-off. Low lignin is good (easier to break down) as long as the lines stand up because we have to look at it in terms of maximizing economic yield per acre. So we’re interested to see if there is a natural variant out there that makes plants lodge.”

Brown said that one of the major advantages of this study is that the researchers are working with lines that are photoperiod sensitive (no flowering). “We are doing association mapping to identify regions of the genome that control all of the different traits—compositional traits, yield traits, and agronomic traits such as lodging and disease. Usually with association mapping one of the big problems is variation in flowering times or maturity, preventing you from comparing apples to apples. By comparing disease or drought resistance across a group of lines with a varying flowering time, you are confusing the maturity variation with everything else. I think we can minimize that or eliminate that in our study because all of these lines are not going to flower or very few should flower.

“I am optimistic that this will be a powerful study to detect small, subtle compositional changes,” he added.  

Brown and his team characterized 400 lines of biomass sorghum in a previous study and will add 200 more lines that have already been genotyped as part of a study on 1,000 biomass sorghum lines at Kansas State University. The sorghum lines will then be grown at U of I, and Markus Pauly, a researcher from Berkeley, will do the compositional work for the study. Pauly, a co-PI on the grant, was also awarded funding through the USDA/DOE program.

Because ideal composition varies depending on the type of pretreatment process (how a producer gets energy from the biomass sorghum) being used, Brown said he hopes the study will provide data that can be combined and made available as trait indexes so that best lines can be identified based on the pretreatment being used.

“A lot of people are waiting to see where bioenergy goes in the next 10 years. We know we can get a certain price for corn at the elevator, and there are certainly a number of ethanol plants, but not a lot of producers are using biomass at this point,” Brown said. “We hope we’re going to find something that really drives down the cost of production and really makes a difference. No one has really looked at this amount of detail before.”

The full article on the USDA/DOE program can be read online at http://www.csrees.usda.gov/newsroom/news/2014news/07171_bioenergy_prod.html.

Sacks’s previous study, “A footprint of past climate change on the diversity and population structure of Miscanthus sinensis,” was published in the Annals of Botany and is available online at http://aob.oxfordjournals.org/content/114/1/97.long.