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Sorghum research looks at manipulating lignin

End result could be better potential for cellulosic biomass.

Curt Arens

March 5, 2015

2 Min Read

Over the past 15 years, grain sorghum plantings in Nebraska have fallen off by almost 75%. In 2012, only 165,000 acres were planted to sorghum in the state.

If sorghum is to make a comeback, new uses and new research will be needed to improve genetics and to provide new ways to utilize this versatile crop. One of the ongoing research projects that is being conducted at the USDA Agricultural Research Service in Lincoln looks at modifying lignin within sorghum genetics to provide greater potential for cellulosic and thermal bioenergy.

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One process in the manufacture of biofuels is through cellulosic biomass being broken down into sugars that can be fermented into biofuels. Cell wall lignin plays an important role in that break down process.

Over the past 30 years, ARS sorghum research has found brown midrib, or bmr, mutants that reduce lignin content and alter lignin composition in the cellulosic biomass of sorghum, according to USDA ARS research molecular biologist, Scott Sattler. Seed companies and numerous government agencies and academic institutions, including the University of Nebraska, have bmr germplasm, particularly in forage-type sorghums, Sattler says.

As part of the studies, specific bmr genes, including bmr6 and bmr12, have been identified by researchers to impair the last steps in lignin synthesis. If lignin synthesis can be disrupted, this would increase ethanol production efficiency.

This is just the beginning. The goal is to find new genes and new ways to impair lignin. "We identified more mutants different from bmr6 and bmr12," Sattler says. "Now, we'd like to see what they do to improve digestibility for cattle or efficiency in cellulosic ethanol production. The goal is to see how low we can push lignin biologically and get a plant that still survives."

So far, studies have found that bmr6 and bmr12 do not increase susceptibility to fungal pathogens like stalk rot, and in fact, may in some instances perform a tad better than wild type sorghum, he says.

This project has also developed grain sorghum germplasm with white grain and tan plants, which could potentially serve the special target audience of gluten-free food producers for consumers with celiac disease. At the same time, Sattler says that ARS researchers have found that tan plants producing white grain still have a good level of resistance to grain mold and other pathogens.

You can learn more about this project by reading an upcoming print article in Nebraska Farmer or by contacting Sattler at 402-472-5987.

About the Author(s)

Curt Arens

Editor, Nebraska Farmer

Curt Arens began writing about Nebraska’s farm families when he was in high school. Before joining Farm Progress as a field editor in April 2010, he had worked as a freelance farm writer for 27 years, first for newspapers and then for farm magazines, including Nebraska Farmer.

His real full-time career, however, during that same period was farming his family’s fourth generation land in northeast Nebraska. He also operated his Christmas tree farm and grew black oil sunflowers for wild birdseed. Curt continues to raise corn, soybeans and alfalfa and runs a cow-calf herd.

Curt and his wife Donna have four children, Lauren, Taylor, Zachary and Benjamin. They are active in their church and St. Rose School in Crofton, where Donna teaches and their children attend classes.

Previously, the 1986 University of Nebraska animal science graduate wrote a weekly rural life column, developed a farm radio program and wrote books about farm direct marketing and farmers markets. He received media honors from the Nebraska Forest Service, Center for Rural Affairs and Northeast Nebraska Experimental Farm Association.

He wrote about the spiritual side of farming in his 2008 book, “Down to Earth: Celebrating a Blessed Life on the Land,” garnering a Catholic Press Association award.

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