Mapping Quantitative Trait Loci Associated With Resistance to Aflatoxin Accumulation in Maize Inbred Mp719

Abstract

Aflatoxins are carcinogenic and toxic compounds produced principally by fungal species Aspergillus flavus (Link: Fries) and A. parasiticus (Speare), which are common contaminants of food and feed. Aflatoxins can be found at dangerously high levels and can readily contaminate pre-harvest maize (Zea mays L.) grain. Sources of resistance to aflatoxin accumulation in maize have been identified, however, the highly quantitative nature and complex inheritance of this trait have limited the introgression of aflatoxin accumulation resistance into agronomically desirable lines. Mapping of quantitative trait loci (QTL) was performed on a bi-parental population comprised of 241 F2:3 families derived from the cross of inbred lines Mp705 (susceptible) × Mp719 (resistant). The mapping population was phenotyped in replicated field trials in three environments for resistance to aflatoxin accumulation under artificial inoculation with an A. flavus spore suspension. The genetic linkage map was constructed with 1,276 single nucleotide polymorphism (SNP) and simple sequence repeat (SSR) molecular markers covering a total genetic distance of 1,642 cM across all ten maize chromosomes. Multiple interval mapping revealed that majority of the aflatoxin-reducing alleles and the source for the larger effect QTL identified in this study were contributed from Mp719, the resistant parent. Two QTL identified on chromosome 1 (bin 1.06-1.07) and chromosome 3 (bin 3.09) were the most stable across different environments and when combined, explained 24.6% of the total phenotypic variance across all three environments. Results from the study showed that these chromosomal regions harbor important QTL for influencing aflatoxin accumulation, which is consistent with previous reports with other different mapping populations. These stable QTL were the most promising for controlling aflatoxin accumulation in maize grain. Identifying beneficial alleles derived from Mp719 and closely linked molecular markers through QTL analysis for implementation of MAS could accelerate breeding efforts to reduce aflatoxin accumulation in maize.

Updating the Methodology of Identifying Maize Hybrids Resistant to Ear Rot Pathogens and Their Toxins—Artificial Inoculation Tests for Kernel Resistance to Fusarium graminearum, F. verticillioides, and Aspergillus flavus

“…As a similar result was reported recently [ 25 ]; we concluded that there is no reason to test their resistance separately. The only reason for using F. culmorum is its lower temperature requirement; therefore, in cooler summers, higher infection rates can be achieved than working with only F. graminearum [ 73 ].…”

Mapping quantitative trait loci for aflatoxin accumulation resistance in two populations containing resistant maize inbred Mp717

“…of the QTL (Edwards, 1992). To find markers linked to preharvest aflatoxin accumulation resistance, several QTL mapping and genome-wide association studies have been conducted (e.g., Brooks et al, 2005;Dhakal et al, 2016;Farfan et al, 2015;Warburton et al, 2009Warburton et al, , 2011Warburton et al, , 2015Womack et al, 2020).…”

“…Markers for the quantitative trait loci (QTL) correlated with resistance could be used for marker‐assisted selection (MAS) and “targeted introgression” of the QTL (Edwards, 1992). To find markers linked to preharvest aflatoxin accumulation resistance, several QTL mapping and genome‐wide association studies have been conducted (e.g., Brooks et al., 2005; Dhakal et al., 2016; Farfan et al., 2015; Warburton et al., 2009, 2011, 2015; Womack et al., 2020).…”

High-Density Genetic Linkage Map Construction Using Whole-Genome Resequencing for Mapping QTLs of Resistance to Aspergillus flavus Infection in Peanut

“…Aflatoxin contamination, which is caused by a pathogen, namely, Aspergillus flavus , is a huge threat to the peanut industry and other important crops such as corn, rice, and wheat (Mahato et al, 2019 ; Womack et al, 2020 ). Contaminated agricultural products could endanger the health of human beings and animals (Pittet, 1998 ; Desjardins, 2003 ; Kew, 2013 ).…”