A Large Transposon Insertion in the Promoter Increases Stalk Strength in Maize.

Stalk lodging, which is generally determined by stalk strength, results in considerable yield loss and has become a primary threat to maize () yield under high-density planting. However, the molecular genetic basis of maize stalk strength remains unclear, and improvement methods remain inefficient. Here, we combined map-based cloning and association mapping and identified the gene underlying a major quantitative trait locus for stalk strength in maize. A 27.2-kb transposable element insertion was present in the promoter of the gene, which encodes an F-box domain protein. This transposable element insertion repressed the transcription of , leading to the increased cellulose and lignin contents in the cell wall and consequently greater stalk strength. Furthermore, a precisely edited allele of generated through the CRISPR/Cas9 system resulted in plants with a stronger stalk than the unedited control. Nucleotide diversity analysis revealed that the promoter of was under strong selection in the maize stiff-stalk group. Our cloning of reveals a case in which a transposable element played an important role in maize improvement. The identification of and our edited allele pave the way for efficient improvement of maize stalk strength.