|SCAPIM, C. - University Of Maringa|
|UHDRE, R. - Washington State University|
|THRASH, A. - Mississippi State University|
Submitted to: Toxins
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/27/2022
Publication Date: 10/28/2022
Citation: Warburton, M.L., Jeffers, D., Smith, J.S., Scapim, C., Uhdre, R., Thrash, A., Williams, W.P. 2022. Comparative analysis of multiple GWAS results identifies metabolic pathways associated with resistance to A. flavus infection and aflatoxin accumulation in maize. Toxins. 14(11). Article 738. https://doi.org/10.3390/toxins14110738.
Interpretive Summary: Many crop species including maize can be infected by fungi of the genus Aspergillus, which can cause ear rots or produce toxins that are carcinogenic and detrimental to human and animal health. To speed production of new, resistant hybrids, breeders need to know what traits or genes to select for among the lines of their breeding populations. This review looked at four genetic association studies on aflatoxin accumulation in maize populations using a method to see which genes, working together in metabolic pathways, were most important for reducing accumulation of the toxin. We then present the presents genes, metabolic pathways, and specific traits identified in these past genetic association studies that could be used by breeders for selection. This should enable the more efficient identification of resistant lines and creation of new resistant hybrid varieties for US farmers.
Technical Abstract: Aflatoxins are carcinogenic secondary metabolites secreted by some species of Aspergillus fungi, which also cause ear rots in maize. Aflatoxins cause multiple health problems and economic damage to farmers with affected grain, and most commercial corn hybrids are susceptible to infection by these fungi. The creation of corn lines resistant to Aspergillus fungi or the accumulation of aflatoxins would be aided by knowing the pertinent alleles and metabolites associated with resistance in corn lines. Multiple QTL and association mapping studies have uncovered several dozens of potential genes, but each with a small effect on resistance, and making sense of how they work together is complicated. A metabolic pathway analysis such as can be performed with the Pathway Association Study Tool (PAST) could be of use and has now been performed on aflatoxin accumulation resistance in four Genomewide Association Studies. The present review compares the outputs of these pathway analyses and seeks common metabolic mechanisms underlying each. Genes, pathways, metabolites, and mechanisms highlighted here can contribute to the selection of new resistant lines at the level of the phenotype via measurement of more specific and highly heritable resistance-related traits; the genes via marker assisted selection; and the pathways using genomic selection with multiple SNPs linked to all the genes in resistance-related pathways.