Activity of transgenically expressed maize defensive genes and proteins against the biotrophic maize pathogen Ustilago maydis

Authors: Dowd, Patrick; Naumann, Todd; Johnson, Eric

Submitted to: Plant Gene
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/23/2026
Publication Date: 2/24/2026
Citation: Dowd, P.F., Naumann, T.A., Johnson, E.T. 2026. Activity of transgenically expressed maize defensive genes and proteins against the biotrophic maize pathogen Ustilago maydis. Plant Gene. https://doi.org/10.1016/j.plgene.2026.100583.
DOI: https://doi.org/10.1016/j.plgene.2026.100583

Interpretive Summary: Corn is one of the most important crops for American farmers, but its production and profitability are often hindered by fungal diseases and pests. Developing corn varieties that resist a wide range of diseases and pests has been challenging because these invaders use different strategies to bypass plant defenses. To tackle this issue, ARS scientists in Peoria, Illinois, conducted a series of experiments. They tested whether corn genes, previously known to inhibit certain fungal pathogens and pests, could also be effective against other fungal pathogens with different strategies. The study identified several genes that provide broad-spectrum defense against a variety of corn pathogens and pests. This discovery is crucial for developing more disease-resistant corn varieties, which will benefit growers, end users, and consumers.

Technical Abstract: Maize is one of the most important grain crops in the world, but production is limited by many diseases, some of which cause toxins to accumulate in grain. Some studies have identified potential maize resistance genes for necrotrophic pathogenic fungi that have been validated, but such is not the case for biotrophic fungi. Transgenic callus tissue constitutively expressing several different maize genes previously demonstrated to be effective against both insects and necrotrophic Fusarium pathogens was evaluated for efficacy against the biotrophic maize pathogen Ustilago maydis. Callus containing genes coding for chitinase A and chitinase 2, defensin, E2F2, geranyl geranyl transferase, hydrolase, maizewin and metallothionein significantly retarded growth of U. maydis compared to controls. Callus containing the chalcone isomerase 3 gene enhanced U. maydis growth compared to control callus, which may be related to induction of the jasmonate defensive pathway previously demonstrated. The available heterologously produced and purified proteins chitinase A, maize hydrolase, maizewin, and metallothionein reduced growth of U. maydis when added at 1000 ppm or less to freeze dried media disks. This study demonstrates that there are several genes that can be effective against both biotrophic and necrotrophic maize pathogens, but in some cases genes that confer resistance to one type of pathogen can increase susceptibility to another. This information will help the development of more disease resistant maize lines, leading to more sustainable production benefitting growers, end users, and consumers.