Setting the stage for the next generation: Epigenetic reprogramming during sexual plant reproduction

Abstract

During their life cycle, plants are faced with multiple environmental challenges which they have to contend with in order to survive and be able to reproduce. The way plants respond to stress results from modifications in gene expression that seem to be at least partially mediated by changes in the epigenetic landscape. Epigenetic marks can be stably propagated through cell divisions, be transmitted to the next generation, or just be transiently established but erased later in the plant life cycle. The transition from sporophyte to a gametophytic life phase is marked by an extensive epigenetic reconfiguration that leads to specification and differentiation of haploid male and female gametes holding distinct epigenetic states. Reshuffling of the parental epigenomes through fertilization tailors the fate of two distinct fertilization products, the zygote and the nourishing endosperm, ultimately contributing to re-establish embryo pluripotency and epiallele inheritance to the next generation. In this chapter, we describe recent advances obtained by genome-wide, cell-type-specific DNA methylomes of gametophytic stages and discuss how previously unknown (epi) genetic regulatory mechanisms occurring during gametogenesis may contribute to understand how genome integrity and stability is preserved during gametogenesis and fertilization and its impact in post-fertilization development.