Control of seed mass and seed yield by the floral homeotic gene APETALA2

APETALA2 (AP2) is best known for its role in the regulation of flower meristem and flower organ identity and development in Arabidopsis. We show here that AP2 also plays an important role in determining seed size, seed weight, and the accumulation of seed oil and protein. We demonstrate genetically that AP2 acts through the maternal sporophyte and endosperm genomes to control seed weight and seed yield. Thus, AP2 functions outside the boundaries of flower meristem and flower organ development to affect agronomically relevant traits in Arabidopsis.