Genome-Edited Maize Expressing Two Native Genes Confers Broad-Spectrum Resistance to Northern Corn Leaf Blight.

Area of Science:

• Plant genetics
• Agricultural biotechnology
• Crop improvement

Background:

• Northern corn leaf blight (NCLB) causes significant maize yield losses, up to 50%.
• Conventional breeding for NCLB resistance is slow and can introduce undesirable traits.
• Genome editing offers a precise method for introducing resistance genes without linkage drag.

Purpose of the Study:

• To develop NCLB-resistant maize hybrids using CRISPR-Cas9 genome editing.
• To precisely integrate novel resistance genes into elite maize inbred lines.
• To evaluate the efficacy and yield impact of genome-edited resistance traits.

Main Methods:

• Identified NCLB resistance gene NLB18-R, allelic to Htn1 and Ht2/Ht3.
• Utilized CRISPR-Cas9 to replace susceptible allele NLB18-S with NLB18-R in elite maize.
• Inserted NLB18-R and Ht1-R into linked sites and combined via genetic crossing.

Main Results:

• Genome-edited maize lines showed enhanced resistance to NCLB (Setosphaeria turcica races 0, 1, 23N).
• No significant yield differences were observed in field trials for edited lines compared to controls.
• Successfully stacked NLB18-R and Ht1-R resistance genes in maize.

Conclusions:

• CRISPR-Cas9 genome editing enables rapid development of maize with broad-spectrum NCLB resistance.
• This approach avoids linkage drag associated with conventional breeding.
• Genome editing is a viable tool for creating commercial-grade disease-resistant maize hybrids.