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