| Abstract Detail
Reproductive Development Palanivelu, Ravishankar [1], Drews, Gary [2]. Synergid Cell Death in Arabidopsis is Triggered Following Direct Interaction With the Pollen Tube. During angiosperm reproduction, one of the two synergid cells within the female gametophyte undergoes cell death prior to fertilization. Synergid degeneration is an essential step because the pollen tube enters the female gametophyte by growing into the synergid cell that undergoes cell death and releases its two sperm cells within the degenerating synergid cytoplasm to effect double fertilization. In Arabidopsis and many other species, synergid cell death is dependent upon pollination. However, the mechanism by which the pollen tube causes synergid cell death is not understood.
As a first step toward understanding this mechanism, we defined the temporal relationship between pollen tube arrival at the female gametophyte and synergid cell death by performing live-imaging of pollen tube growth and synergid cell death using an in vitro pollen tube guidance assay. To observe pollen tube growth, pollen tubes were marked with DsRed driven by the pollen-specific LAT52 promoter. To observe synergid degeneration, we specifically labeled the synergid cells with green fluorescent protein (GFP) expressed from the MYB98 promoter and used loss of the synergid GFP signal as an indicator of synergid degeneration. Using real-time observation of these two events in vitro, we demonstrate that synergid cell death initiates after the pollen tube arrives at the female gametophyte but before pollen tube discharge. Our results support a model in which the pollen tube induces a physiological cell death program following direct interaction with the synergid cell.
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1 - University of Arizona, Plant Sciences, 303 Forbes Building, University of Arizona, Tucson, AZ, 85721, United States
2 - University of Utah, Dept. of Biology
Keywords:
pollen tube
synergid
Programmed Cell Death
degeneration
female gametophyte
embryosac
guidance.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P28038
Abstract ID:1311 |
