Towards a Comprehensive Understanding of Genetic Determinants Underlying Fusarium Resistance and Mycotoxin Contamination in Maize

Climate change is aggravating the incidence of several maize diseases worldwide. Fusarium verticillioides is a prevalent fungal pathogen affecting all growth stages of maize, triggering several diseases including seedling rot and ear rot. The breeding of resistant maize genotypes is the most effective way to achieve sustainable control of Fusarium infection and may take advantage of the identification of genes and loci responsible for natural disease resistance. Significant advances have been made in the development of transcriptomic, genetic and genomic information for maize, F. verticillioides moulds, and their interactions over recent years. Several quantitative trait loci (QTL) and single-nucleotide polymorphism markers for resistance to Fusarium deriving from QTL mapping and genome-wide association studies have been described in three different maize populations: 1. Bi-parental population; 2. Association mapping panel; 3. Multi-parent Advanced Generation Inter Crosses (MAGIC). To guide the identification of candidate genes within the identified QTL, transcriptomic and sequencing information have been exploited. Promising candidate genes associated with disease resistance and pathogen related-mechanisms at the Fusarium resistant loci have been identified on maize chromosomes 4, 5 and 7. Many of the identified candidates genes offer hints to key metabolic pathways that may have a significant effect on reducing Fusarium infection. Measuring Fusarium resistance in open field could confirm and support their direct use in maize breeding either through crosses or genome editing approaches.