Location: Corn Host Plant Resistance ResearchTitle: Genome-wide association and metabolic pathway analysis of corn earworm resistance in maize
|TANG, JULIET - Us Forest Service (FS)|
|THRASH, ADAM - Mississippi State University|
|Smith, Jesse - Spencer|
|XU, WENWEI - Texas A&M University|
|MURRAY, SETH - Texas A&M University|
Submitted to: The Plant Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/27/2017
Publication Date: 12/7/2017
Citation: Warburton, M.L., Womack, E.D., Tang, J.D., Thrash, A., Smith, J.S., Xu, W., Murray, S.C., Williams, W.P. 2017. Genome-wide association and metabolic pathway analysis of corn earworm resistance in maize. The Plant Genome. 11(1):170069. https://doi.org/10.3835/plantgenome2017.08.0069.
Interpretive Summary: Maize (Zea mays mays L) is a staple crop of economic, industrial, and food security importance. Damage to the growing ears by corn earworm, Helicoverpa zea (Boddie), is a major economic burden and increases secondary fungal infections and mycotoxin levels. Here, we have used a new analysis tool to determine which genes and which cellular pathways are being used by resistant plants in order to stop corn earworms from feeding on corn ears. Genes and pathways involved in three separate mechanisms seemed to be important. First, creating a stronger cell wall seems to make it harder for worms to eat into kernels. Second, some plants are making compounds that deter or poison the worm. And third, some resistant plants seem to be growing faster than susceptible plants, perhaps maturing the ear before the number of hungry worms grows to their peak in the late summer. This information will help breeders create lines that will resist corn ear worms without the use of artificial insecticides or GMO technology.
Technical Abstract: Maize (Zea mays mays L) is a staple crop of economic, industrial, and food security importance. Damage to the growing ears by corn earworm, Helicoverpa zea (Boddie), is a major economic burden and increases secondary fungal infections and mycotoxin levels. To identify biochemical pathways associated with native resistance mechanisms, a genome-wide association analysis was performed followed by pathway analysis using a gene-set enrichment-based approach. The gene-set enrichment exposed cumulative effects of genes in pathways to identify those that contributed the most to resistance. SNP-trait associations were linked to genes including transcription factors, protein kinases, hormone responsive proteins, hydrolases, pectinases, xylogluconases, and the gene flavonol synthase (in the maysin biosynthesis pathway). The most significantly associated metabolic pathways identified included those that modified cell wall components, especially homogalacturonan, wax esters, and fatty acids; those involved in antibiosis, especially DIMBOA, flavonoids, and phenolics; and those involved in plant growth, including nitrogen uptake and energy production. The pathways identified in this study, and especially the cell wall associated pathways, here identified for the first time, provide clues to resistance mechanisms that can guide the identification of new resistant ideotypes and candidate genes for creation of resistant maize germplasm via selection of natural variants or gene editing.