Fusarium Pathogens

The pathogenic fungus Fusarium threatens the integrity of corn crops in the form of blights and by producing mycotoxins, which can affect human and animal health if they enter the food chain. Efforts to control its spread are complicated because the fungus often resides in seeds; however, biological control microorganisms offer a promising organic alternative to chemical seed treatments.

In the Fall of 2013, OFRF awarded Lucas Nebert, a PhD candidate at the University of Oregon, a $13,000 grant to explore the use of indigenous seed-inhabiting microorganisms as biological control agents against Fusarium in corn. With field research completed in 2014, Nebert spent most of 2015 processing the seed and plant samples for DNA-based pathogen detection and next-generation DNA sequencing. He submitted his final report to OFRF in January.

Nebert conducted field trials with organic farmers Andrew Still and Sarah Kleeger of Adaptive Seeds, and Jeff Bramlett and Carri Heisler of Pitchfork and Crow. The collaborating organic farmers grow Cascade Ruby-Gold, a hardy, open-pollinated flint corn variety that was bred and adapted to Oregon’s Willamette Valley. The farms, which were not afflicted with noticeable Fusarium pathogen pressure, were used to test the overall health of treated plants, and the persistence of microbial inoculants across generations. Ultimately, the goal was for the methods employed in this research to be transferrable to other local efforts for preventative management of seed-borne diseases.

“With the advent of better DNA methods such as next-generation DNA sequencing, we are able to study microbial ecology for more depth and clarity than ever before,” said Nebert. “In agriculture, we can use this technology to understand how practices affect the composition and integrity of microbial communities in the soil and inside our crops.”

While research into seedborne microbes is still in its infancy, Nebert and his team hope to generate more interest with the Community Research Network, which enables OP corn seed growers to submit seeds for microbial community analysis. To date, they have received 70 seed samples from over a dozen corn varieties, which are being processed in parallel with seed and crown samples from the OFRF funded experiment. This larger data set, which includes over 10 million DNA sequences, will enable Nebert to conduct broader experiments across cultivars, geographies and farming methods. The data will be shared freely online.

The University of Oregon granted Nebert a full-year fellowship for 2015-2016 to expand the Community Research Network and develop a business or non-profit for testing seedborne microbes. “We will continue to take the methods and insights we learned from the OFRF funded project to build capacity for larger-scale testing of microbes,” said Nebert.

Conclusions from the study are available in Nebert’s report: Managing indigenous seed-inhabiting microbes for biological control against Fusarium pathogens in corn.