Pollen PCD, as seen by DNA fragmentation (green), is induced by actin filament destabilization.
Some plants prefer not to be fertilized by pollen grains that are genetically similar to themselves. These plants express self-incompatibility (S) proteins. A match between the pistil's S-proteins and the pollen's S-allele triggers a rapid calcium influx, actin filament destruction, and pollen cell death.
Several years ago, the researchers noticed that the amount of actin depolymerization far exceeded that required to inhibit pollen tube growth. The persistent actin destabilization also resembled that associated with animal cells about to undergo programmed cell death (PCD).
The authors now find that blocking actin depolymerization prevents pollen cell death in self-incompatible plants. Inducing actin depolymerization, on the other hand, activated pollen cell death. The...
