FROMLINE: Lauren Quinn

Newswise – URBANA, Ill. — In a changing climate, corn farmers must be prepared for anything, including new and changing disease dynamics. Since it is impossible to predict which harmful disease will emerge in a given year, corn with resistance to multiple diseases would be a big win for farmers. Now, University of Illinois Urbana-Champaign Researchers are bringing the industry closer to this goal.

Goss wilt, a bacterial disease, and fungal diseases such as leaf spot, northern corn leaf blight, and southern corn leaf blight are of concern to farmers throughout the Midwestern United States and, in some cases, worldwide. The study, published in G3 genes|genomes|geneticsuncovers genomic regions associated with resistance to all four diseases.

“Not only did we find regions in the genome that confer resistance to each disease, but we also identified a handful of experimental maize lines that were resistant to all of these diseases. “These findings should help industry develop materials that are resistant to multiple diseases at the same time,” he said Tiffany Jamannlead author of the new study and associate professor in the Department of Crop Sciencespart of College of Agricultural, Consumer and Environmental Sciences (ACES) at the U. of I.

The team performed multiple strategic crosses between disease-resistant and susceptible maize lines, allowing them to map resistance traits to specific locations in the genome. Currently, these regions are quite large, encompassing hundreds of individual genes. If there are specific genes with outsized effects, they have not yet been identified.

Nevertheless, identifying important regions is helpful because disease resistance is rarely due to a single gene. Actually it is additive or quantitative power of multiple genes working together can mean more lasting resilience. There is insurance when a pathogen finds a way to circumvent a particular resistance mechanism. Interestingly, this durability can even be effective against different groups of pathogens.

“We found 19 regions associated with resistance to bacterial Goss wilt. Some of these regions are also involved in resistance to fungal pathogens,” said Jamann. “This makes it possible to breed resistance against several diseases at the same time using the same genetic regions.”

Fungi and bacteria are biologically very different, but both must find ways to enter the plant, move around and reproduce. Jamann says it’s possible that resistance genes trigger changes in the plant’s vascular system that make it harder for both types of pathogens to move, but she still can’t say exactly how the genes help plants protect themselves. However, she is working on it, thanks to a Grant 2022 from that National Science Foundation.

Because of this work, although the team identified three corn lines that are resistant to all four diseases, it will still be a while before farmers can purchase seeds for multi-resistant corn. First, Jamann’s team will closely map the regions highlighted in this study to find any genes with large effects, then pass this information on to breeders who can develop robust new hybrids. Nevertheless, says Jamann, there is widespread resistance.

The study, “Identification of loci conferring resistance to four foliar diseases of maize,” was published in G3 genes|genomes|genetics [DOI: 10.1093/g3journal/jkad275]. Authors include Yuting Qiu, Pragya Adhikari, Peter Balint-Kurti and Tiffany Jamann. The research was supported by the USDA Hatch Project ILLU-802-985 and the National Science Foundation under grant no. 2154872. Any opinions, findings, conclusions, or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.

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