Gametes to zygotes to self-cloning plants: the importance of being egg-centric

The Annals of Botany Annual Oxford Lecture

For both plants and animals, the transition of a fertilised egg cell into a zygote is a critical step in sexual reproduction. In animals, early embryonic divisions rely on maternally provided gene products, whereas in plants, zygotic genome activation occurs before the first embryonic division. Using a rice model, transcription factors encoded by the paternal genome can be shown to play a key role in this triggering this transition. Manipulation of the corresponding genes in eggs bypasses fertilisation and results in parthenogenesis. When combined with editing of meiosis genes, plants that reproduce stably as genetic clones can be generated. With these gene alterations, hybrid rice propagated through seeds maintains uniform hybrid vigour in subsequent generations. Fixation of hybrid vigour in crop plants has broad implications for the availability of high-yielding hybrid seeds at low costs for subsistence farmers.