United States Department of Agriculture Fargo, North Dakota
Body of Abstract: Crop architecture is important for light capture and tightly affects economic yield under field condition. In this study, we conducted map-based cloning of the Liguleless1 (Lig1) regulating leaf angle in barley. Loss-of-function mutant of lig1 obtained by fast neutron-mutagenesis is deficient in the formation of the ligule and auricle, resulting in smaller leaf angles. The compact architecture caused by erect leaves is desirable to increase yield with high planting density. Genetic mapping anchored the Lig1 gene onto 2H within an ⁓300-kb region. DNA sequencing indicated that a genomic deletion of 20-kb in the mutant occurred to the gene model HORVU.MOREX.r3.2HG0202650, which encodes a putative SQUAMOSA promoter-binding protein-like (SPL) transcription factor. Phylogenetic analysis suggested the SPL in barley might be a homolog of Zmlg1 and TaSPL8 regulating leaf angle in maize and wheat, respectively. Using CRISPR technology, we knocked out the SPL-encoding gene and phenocopied the Lig1 mutant. Therefore, HORVU.MOREX.r3.2HG0202650 is indeed the Lig1 gene. Cloning of Lig1 demonstrated that the SPL transcription factor is conserved in monocots, providing a target for gene manipulation to maximize light interception capacity in high planting density.