Review: Embryo-endosperm interactions ($) (Annu Rev Plant Biol)

Angiosperm seed formation is an incredibly complex process, considering that it requires coordinating the development of three distinct structures –the embryo, the endosperm and the seed coat– in a small space. However, Doll and Ingram show us that angiosperms faced this challenge by evolving a complex network of interactions between these compartments, especially between the embryo and the endosperm. These two structures rapidly become symplastically isolated after double fertilization, however, this does not impede further communication between these tissues. In fact, several vital processes in seed development, such as nutrient mobilization, embryo expansion and embryo cuticle formation, depend on signaling peptides, phytohormones, and other compounds being exported to the apoplast between the two tissues. Moreover, embryo-endosperm interactions are essential to dormancy acquisition and germination. Further studies are required to understand the nature of the apoplastic interface between the embryo and the endosperm and the molecular and genetic basis that underpins molecule trafficking. Still, this fascinating review surely provides a promising starting point for exciting and new research in this area. (Summary by Carlos A. Ordóñez-Parra @caordonezparra) Annu. Rev. Plant Biol. 10.1146/annurev-arplant-102820-091838