BnaC01.BIN2, a GSK3-like kinase, modulates plant height and yield potential in Brassica napus

Using map-based cloning and transgenic transformation, we revealed that glycogen kinase synthase 3-like kinase, BnaC01.BIN2, modulates plant height and yield in rapeseed. The modification of plant height is one of the most important goals in rapeseed breeding. Although several genes that regulate rapeseed plant height have been identified, the genetics mechanisms underlying rapeseed plant height regulation remain poorly understood, and desirable genetic resources for rapeseed ideotype breeding are scarce. Here, we map-based cloned and functionally verified that the rapeseed semi-dominant gene, BnDF4, greatly affects rapeseed plant height. Specifically, BnDF4 encodes brassinosteroid (BR)-insensitive 2, a glycogen synthase kinase 3 primarily expressed in the lower internodes to modulate rapeseed plant height by blocking basal internode-cell elongation. Transcriptome data showed that several cell expansion-related genes involving auxin and BRs pathways were significantly downregulated in the semi-dwarf mutant. Heterozygosity in the BnDF4 allele results in small stature with no marked differences in other agronomic traits. Using BnDF4 in the heterozygous condition, the hybrid displayed strong yield heterosis through optimum intermediate plant height. Our results provide a desirable genetic resource for breeding semi-dwarf rapeseed phenotypes and support an effective strategy for breeding rapeseed hybrid varieties with strong yield heterosis.