Transgenerational polarity axis inheritance during Ceratopteris embryogenesis

For sexually reproducing organisms to pass on their genetic information, progeny must successfully establish. Various life history strategies have evolved, using either dispersal of large numbers of progeny or intensive nurturing of a few. Most plants use the former strategy, but ferns generate a single embryo in the exact same location as the mother, and it is unknown how progeny success is promoted, or how embryogenesis is adapted. By studying Ceratopteris richardii embryogenesis, we find that maternal tissues guide orientation of the early embryo body axis, thus aligning its root pole towards the homologous maternal rhizoids. We find that axis polarity inheritance is mediated by maternal tissue mechanical patterns, and thus identify a robust mechanism for progeny establishment as a nurturing strategy in plants.