Polycomb repression of the asexual embryo

In angiosperms, the proliferation and differentiation of egg and central cells need to be repressed before fertilization. Autonomous endosperm development has been observed and well-studied in Arabidopsis mutants of FERTILIZATION INDEPENDENT SEED (FIS)-class POLYCOMB REPRESSIVE COMPLEX 2 (PRC2), but how defects of PRC2 components affect embryo development remains unclear. Wu et al. now describe an essential clue for understanding parthenogenetic embryogenesis from the rice double mutant osfie1 osfie2 .