Sudden death syndrome causes annual losses in U.S. soybean yields in excess of $274 million. Managing the disease might be a matter of timing, according to recent research findings at Michigan State University.
Researchers compared how the fungus F. virguliforme – which causes sudden death syndrome – interacts with both soybean and corn crops. They studied why corn remains healthy despite fungal invasion.
Corn and soybeans are often rotated on the same land to prevent sudden death syndrome from spreading. But the strategy doesn’t stop soybeans from being affected by the fungus, said Amy Baetsen-Young, a former doctoral student in plant soil and microbial sciences at Michigan State University.
“We used that observation as our starting point to look for genes that allow corn to show no disease symptoms to the same fungus that debilitates soybeans,” she said.
The researchers found that although fungus also invades corn plants, corn reacts very early. That leads to a robust defense response and a better chance of remaining healthy, said Huan Chen, a second-year graduate student in the molecular plant sciences program at Michigan State.
The research team took a big-data approach to compare if and how corn and soybeans mount their defense responses when facing the fungus. The researchers found that when the crop mounts a defense response is crucial to maintaining health. Soybean defenses increase seven days after the onset of the fungal invasion, at which point the fungus is in damage mode. Corn defenses take action two days after invasion, which slows the growth of the fungus before it turns damaging.
“Our data also suggest that the fungus is associated with senescence in soybeans,” Chen said. “Although we see senescence in infected soybeans, we aren’t sure if the fungus triggers the soybean to mature so the fungus can grow or if senescence is simply a symptom that appears as the disease develops.”
The research team found that fungal infestation triggers different genetic responses in both crops. The fungus might manipulate the hosts’ metabolism to cause cell death, according to the researchers. The study recently was published in “The Plant Cell.” Visit academic.oup.com and search for "Amy Baetsen-Young" for more information.