Undesirable protein sequence variations in maize genes that confer resistance to fungal pathogens and insect pests

Authors: Lyon, Rebecca; Johnson, Eric; Dowd, Patrick

Submitted to: Plant Gene
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/22/2023
Publication Date: 3/1/2024
Citation: Lyon, R.M., Johnson, E.T., Dowd, P.F. 2024. Undesirable protein sequence variations in maize genes that confer resistance to fungal pathogens and insect pests. Plant Gene. 37. Article 100441. https://doi.org/10.1016/j.plgene.2023.100441.
DOI: https://doi.org/10.1016/j.plgene.2023.100441

Interpretive Summary: Corn is one of the most important grain crops in the world, but significant losses are caused by insects and pathogens. Breeding for corn plants with improved resistance to pests and pathogens has been helpful, but multiple genes appear to be involved in both insect and pathogen resistance. In order to more efficiently breed corn varieties that contain the multiple genes needed for effective resistance to both plant diseases and insect pests, it is necessary to identify corn varieties that have resistance genes that will produce functional resistance proteins. In addition, plant breeding over many years has incorporated resistance genes that are functional and others that have mutations that will likely result in nonfunctional pest resistance. Over the last several years, a number of corn pest resistance genes have been studied, and the entire set of genes contained in many corn inbreds have been identified. This study identified mutations of pest resistance genes in 46 corn inbred lines. Some of these mutations are likely to make the pest resistance gene nonfunctional. However, these mutations can be corrected in the future using modern gene editing methods. This study will provide a helpful resource for plant breeders to identify which mutations in pest resistance genes should be corrected. Restoration of resistance genes will help farmers have corn crops that are more resistant to insects and pathogens.

Technical Abstract: Diseases and insect pests greatly impact the sustainable production of maize. Maize inbred lines have varying resistance to these insects and pathogens. Seven proteins of interest involved in maize resistance to insects and pathogens were chosen to elucidate the differences in amino acid sequences of the proteins in 46 maize inbred lines. These proteins of interest are superlectin, maizewin, hydrolase, geranyl geranyl transferase, quinone oxidoreductase, AIL1, and defensin. The genes superlectin, quinone oxidoreductase, AIL1, and defensin were disrupted in some maize inbreds and conserved in others. These disruptions were single amino acid changes, insertions or deletions that can possibly affect functionality or 3-dimensional shape. These types of disruptions would be expected to increase susceptibility to insects and diseases. Maize inbreds with better sources of functional resistance genes can be incorporated into crops to promote enhanced insect and pathogen resistance.