Identification of the Functional Loci and Candidate Gene Associated with Maize Northern Leaf Blight Resistance in a Multi-Parental Population

Identifying candidate genes associated with resistance to northern leaf blight (NLB) will greatly enhance maize breeding programs aiming at reducing maize grain yield losses caused by NLB. In this study, a multi-parental population (MPP) was constructed consisting of four recombined inbred line (RIL) subpopulations, all sharing a common parent Ye107, for GWAS and linkage analysis. The results revealed the detection of a significant SNP, 5-49193921, from a tropical maize inbred line YML226. This SNP was found to be associated with the gene Zm00001d014471, which encodes a pentatricopeptide repeat (PPR-like) superfamily protein. Furthermore, gene expression analysis showed a positive correlation between the expression of Zm00001d014471 and NLB resistance. Notably, the F 1 generation of YML226 × Ye107 contained the largest number of specific SNPs within the genic region, suggesting that its abundant genetic variation might contribute to its high NLB resistance. Furthermore, there was a specific nonsynonymous SNP (C to T) causing a nucleotide change at position 235, leading to an alteration of an amino acid, which resulted in the modification of a motif in the PPR protein. Our results revealed that tropical maize germplasm YML226 could serve an important genetic resource for NLB resistance. Additionally, previous studies have shown that YML226 is an exceptional elite line derived from CATETO germplasm, exhibiting a higher positive general combining ability for grain yield. Therefore, YML226 holds great promise for the breeding of NLB-resistant maize cultivars in the future.