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ARS Home » Southeast Area » Mississippi State, Mississippi » Crop Science Research Laboratory » Corn Host Plant Resistance Research » Research » Publications at this Location » Publication #381107
Research Project: Enhanced Resistance of Maize to Aspergillus flavus Infection, Aflatoxin Accumulation, and Insect Damage

Location: Corn Host Plant Resistance Research

Title: Association mapping and pathway analysis of ear rot disease caused by Aspergillus flavus in a panel of tropical maize germplasm

Author
item BERTAGNA, FILIPE A. - Universidade Estadual De Maringá
item KUKI, MAURÍCIO - Universidade Estadual De Maringá
item NETO, HUGO - Universidade Estadual De Maringá
item TESSMANN, DAURI - Universidade Estadual De Maringá
item PINTO, RONALD J. - Universidade Estadual De Maringá
item SCAPIM, CARLOS - Universidade Estadual De Maringá
item Williams, William
item Warburton, Marilyn

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/22/2021
Publication Date: 8/30/2021
Citation: Bertagna, F.B., Kuki, M.C., Neto, H.Z., Tessmann, D.J., Pinto, R.B., Scapim, C.A., Williams, W.P., Warburton, M.L. 2021. Association mapping and pathway analysis of ear rot disease caused by Aspergillus flavus in a panel of tropical maize germplasm. Crop Science. 61(6):4128-4138. https://doi.org/10.1002/csc2.20629.
DOI: https://doi.org/10.1002/csc2.20629

Interpretive Summary: Most commercial maize hybrids are susceptible to infection by the fungus Aspergillus flavus, which can create toxic aflatoxins. Long term exposure to aflatoxin can cause liver cancer, stunted growth during childhood and depressed immune systems. Aspergillus ear rot (AER) is especially problematic in tropical environments, but most studies on aflatoxin and AER have been done in temperate or subtropical maize. This study was run on tropical maize, and found several genes and methods by which the plants are resisting AER. Many of these methods have been found in previous studies using similar methods, but some are new. All genes and methods can be used to create new, resistant maize cultivars.

Technical Abstract: Most commercial maize hybrids are susceptible to infection by the fungus Aspergillus flavus, which ultimately leads to high and unsafe levels of aflatoxin under environmental conditions favoring fungal growth and sporulation. Long term exposure to sublethal doses of aflatoxin has been linked to liver cancer, stunted growth during childhood and depressed immune systems. Aspergillus ear rot (AER) is especially problematic in tropical environments, but most gene identification studies have been done in temperate or subtropical maize. Thus, the objectives of this research include identifying and mapping chromosomal regions and genes associated with AER resistance in tropical maize inbred lines via genome-wide association study (GWAS); and tying these genes to metabolic pathways and potential resistance mechanisms. A panel of 320 tropical field corn and popcorn inbred lines were analyzed with phenotypic data for AER collected in two environments after harvest, and a set of 291,633 high-quality polymorphic SNPs generated using genotyping by sequencing. Seven SNPs significantly associated with AER were identified. Pathway analysis identified 56 associated pathways, yielding probable resistance mechanisms related to flavonoid and phytoalexin plant compounds, and also plant signaling via hormones, starch biosynthesis, and general plant growth and metabolism. The results of both analyses were in good agreement, but GWAS and pathway analysis jointly identified more probable candidate genes than either alone.