ISU Researchers Receive Grant To Enhance Soybean Resistance To Sudden Death Syndrome

Researchers at Iowa State University will use a grant totaling more than $5 million to strengthen the genetic resistance of soybeans to sudden death syndrome, a disease that has cost Iowa soybean producers millions in crop losses.

The five-year, $5.35 million grant from the U.S. Department of Agriculture’s National Institute of Food and Agriculture will allow an international team that includes nine ISU researchers to genetically modify soybeans in an attempt to fight off sudden death syndrome more effectively.

Madan Bhattacharyya, an associate professor of agronomy who will lead the research team, began studying sudden death syndrome in soybeans in 2003.  Bhattacharyya said that sudden death syndrome resistance in soybeans is encoded in numerous genes, each playing a small role in an individual plant’s resistance to the disease. Even elite soybean lines carry only partial resistance to the disease, he said. Researchers on the project hope to find new solutions that will provide a stronger resistance.

“Currently, the existing resistance mechanism isn’t strong,” Bhattacharyya said. “We would prefer something that does more to combat the disease.”

Soybean sudden death syndrome is an emerging disease that first appeared in Arkansas in 1971, he said. It’s caused by a Fusarium fungus that infects the roots of the soybean plant. The pathogen has never been detected from the diseased leaves or other above-ground tissues. The research group has recently shown that a small protein produced by the pathogen in the roots is the major cause of foliar soybean sudden death syndrome. The team has also shown that generation of a plant antibody against this protein enhances the disease resistance in transgenic soybean lines.

In 2010, sudden death syndrome cost Iowa soybean producers around $300 million in crop losses, Bhattacharyya said. That same year saw national crop losses approach $1 billion, he said.

“One of the reasons the disease is so devastating is that it begins in the root of the plant, and the pathogen stays in the infected roots,” he said. “By the time disease symptoms become visible in the leaves, it’s too late. There’s no effective fungicide to control the disease.”