Non-Cell Autonomous Mechanisms Regulating Seed Coat Growth
Seed development in flowering plants involves a complex set of developmental processes that are initiated by double fertilization of egg and central cell, leading to the formation of embryo and endosperm, respectively. The seed coat surrounds embryo and endosperm and constitutes the third component of the seed. Although the seed coat is not a fertilization product, its development is started only after fertilization. In the absence of fertilization female gametophytes do not develop and abort. Repression of central cell development is assured by the FERTILIZATION INDEPENDENT SEED (FIS) Polycomb Repressive Complex 2 (PRC2). Recent results from our group revealed that seed coat development is repressed before fertilization by PRC2 complexes acting in maternal tissues surrounding the female gametophyte. This repression is relieved after fertilization by a signal that is formed by the sexual endosperm. Recent work from our group identified the plant hormone auxin as the trigger for seed coat initiation. How auxin initiates the transition from the integuments to the seed coat is one current research goal.
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