The mysterious dialogue between the embryo, endosperm, and seed coat, and its implications for seed traits

The seeds of flowering plants contain three genetically distinct structures: the embryo, which will form a new plant; the endosperm, which nourishes the embryo; and the seed coat, which protects the embryo and endosperm. For a seed to form, these three structures have to communicate and coordinate their development. This communication is not just necessary for seed viability; it also underlies important agronomic traits like seed size. In this review, we outline the current body of knowledge on how the embryo, endosperm, and seed coat communicate with one another during the early stages of seed development. We also discuss the nature and variability of signalling mechanisms across these tissues and the impact of these interactions on seed development and associated agronomic traits, highlighting how understanding these communication pathways can contribute to agricultural biotechnology.