title: Downregulation of egg cell-secreted EC1 is accompanied with delayed gamete fusion and polytubey.
abstract: One major player known to be essential for successful gamete interactions during double fertilization in Arabidopsis thaliana is the recently identified family of egg cell-secreted EC1 proteins. Both gamete fusion events are affected in EC1-deficient female gametophytes. Here, we show that the number of ovules with unfused sperm cells is considerably higher than the number of undeveloped seeds in the same ec1-RNAi knockdown lines. We found that some sperm cells are able to fuse with the female gametes even 2 to 3 days after pollination, as reflected by delayed embryo and endosperm development, and by polytubey. We propose that the egg cell secretes EC1 proteins upon sperm arrival to promote rapid sperm activation, thereby accelerating gamete fusion and preventing polytubey.
authors.affiliation: Cell Biology and Plant Biochemistry; University of Regensburg; Regensburg, Germany.
authors.forename: Svenja
authors.initials: S
authors.lastname: Rademacher
authors.affiliation: Cell Biology and Plant Biochemistry; University of Regensburg; Regensburg, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Sprunck
mesh_terms: D017360:Arabidopsis / Q000166:cytology* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D002459:Cell Fusion; D015536:Down-Regulation; D005306:Fertilization; D056771:Ovule / Q000166:cytology* / Q000378:metabolism*; D010641:Phenotype; D054817:Pollination; D034622:RNA Interference; D012639:Seeds / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins
keywords: CRP; EC1; double fertilization; gamete fusion; polytubey; sperm activation