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Egg cell-secreted EC1 triggers sperm cell activation during double fertilization.

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Author Sprunck Stefanie, Rademacher Svenja, Vogler Frank, Gheyselinck Jacqueline, Grossniklaus Ueli, Dresselhaus Thomas,
Project The Genetic and Molecular Basis of Gametogenesis and Maternal Effects in Arabidopsis
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Original article (peer-reviewed)

Journal Science (New York, N.Y.)
Volume (Issue) 338(6110)
Page(s) 1093 - 7
Title of proceedings Science (New York, N.Y.)
DOI 10.1126/science.1223944

Open Access

Type of Open Access Repository (Green Open Access)


Double fertilization is the defining characteristic of flowering plants. However, the molecular mechanisms regulating the fusion of one sperm with the egg and the second sperm with the central cell are largely unknown. We show that gamete interactions in Arabidopsis depend on small cysteine-rich EC1 (EGG CELL 1) proteins accumulating in storage vesicles of the egg cell. Upon sperm arrival, EC1-containing vesicles are exocytosed. The sperm endomembrane system responds to exogenously applied EC1 peptides by redistributing the potential gamete fusogen HAP2/GCS1 (HAPLESS 2/GENERATIVE CELL SPECIFIC 1) to the cell surface. Furthermore, fertilization studies with ec1 quintuple mutants show that successful male-female gamete interactions are necessary to prevent multiple-sperm cell delivery. Our findings provide evidence that mutual gamete activation, regulated exocytosis, and sperm plasma membrane modifications govern flowering plant gamete interactions.