Rademacher Svenja, Sprunck Stefanie
Cell Biology and Plant Biochemistry; University of Regensburg; Regensburg, Germany.
Plant Signal Behav. 2013;8(12):e27377. doi: 10.4161/psb.27377. Epub 2013 Dec 31.
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.
在拟南芥双受精过程中，已知对成功的配子相互作用至关重要的一个主要因素是最近发现的卵细胞分泌的EC1蛋白家族。在缺乏EC1的雌配子体中，两种配子融合事件均受到影响。在这里，我们表明，在相同的ec1-RNAi敲低系中，带有未融合精子细胞的胚珠数量明显高于未发育种子的数量。我们发现，一些精子细胞甚至在授粉后2至3天仍能够与雌配子融合，这表现为胚胎和胚乳发育延迟以及多精入卵现象。我们提出，卵细胞在精子到达时分泌EC1蛋白以促进精子快速激活，从而加速配子融合并防止多精入卵。
