BnC03UPL3 promoter. BnC03UPL3 promoter

Identifying genetic variation that increases crop yields is a primary objective in plant breeding. We have used association analyses of Brassica napus (oilseed rape/canola) accessions to identify genetic variation in the promoter of a HECT E3 ligase gene, BnaUPL3.C03, which influences seed size and final yield. We establish a mechanism in which UPL3 mediates the proteasomal degradation of LEC2, a master regulator of seed maturation. Reduced UPL3 expression prolongs seed maturation and the expression of lipid biosynthetic genes. Natural variation in BnaUPL3.C03 expression has not yet been exploited in the current Brassica napus breeding pool, and can thus be used as a novel approach to maximize future yields in this important oil crop.