Genome-Wide Association Study and Transcriptome Analysis of Candidate Resistance Genes for Northern Corn Leaf Blight

Area of Science:

• Plant Pathology
• Genetics
• Agronomy

Background:

• Northern corn leaf blight (NCLB), caused by *Setosphaeria turcica*, significantly reduces maize photosynthesis and grain yield.
• Developing NCLB-resistant maize varieties is crucial for mitigating crop losses.
• Understanding resistance mechanisms through gene mapping is key for effective breeding strategies.

Purpose of the Study:

• To evaluate the resistance of diverse maize inbred lines to NCLB.
• To identify genetic markers associated with NCLB resistance using genome-wide association studies (GWAS).
• To explore gene expression patterns related to NCLB resistance through transcriptome analysis.

Main Methods:

• Phenotypic evaluation of 421 maize inbred lines over three years.
• Genome-wide association study (GWAS) using 39,676 SNP markers.
• Comparative transcriptome analysis of resistant and susceptible inbred lines post-infection.
• Gene Ontology (GO) and KEGG pathway enrichment analyses.

Main Results:

• Maize lines showed varying resistance levels, with 1.06% highly resistant (HR) and 34.48% highly susceptible (HS).
• GWAS identified 85 SNPs associated with NCLB resistance, with 11 stable SNPs across environments.
• Transcriptome analysis revealed differentially expressed genes (DEGs) involved in plant defense pathways, particularly in resistant lines.

Conclusions:

• Two candidate genes were identified by integrating GWAS and transcriptome data.
• These findings provide a foundation for cloning NCLB resistance genes.
• The study supports the development of introgression breeding strategies for resistant maize varieties.