Speed dating, rejection, and finding the perfect mate: advice from flowering plants.

Angiosperm pollen tubes extend through pistil tissue to deliver a pair of immotile sperm cells to female gametes for double fertilization. The extended journey of the pollen tube requires extensive cell:cell interactions that guide the pollen tube to its destination and instruct it to stop growing and burst. Once sperm cells are released the molecular exchanges between male and female continue, resulting in sperm activation and gamete fusion.

Three MYB transcription factors control pollen tube differentiation required for sperm release.

In flowering plants, immotile sperm cells develop within the pollen grain and are delivered to female gametes by a pollen tube. Upon arrival at the female gametophyte, the pollen tube stops growing and releases sperm cells for successful fertilization. Several female signaling components essential for pollen tube reception have been identified; however, male components remain unknown.

Gamete fusion is required to block multiple pollen tubes from entering an Arabidopsis ovule.

In double fertilization, a reproductive system unique to flowering plants, two immotile sperm are delivered to an ovule by a pollen tube. One sperm fuses with the egg to generate a zygote, the other with the central cell to produce endosperm. A mechanism preventing multiple pollen tubes from entering an ovule would ensure that only two sperm are delivered to female gametes.

Identification and cardiotropic actions of brain/gut-derived tachykinin-related peptides (TRPs) from the American lobster Homarus americanus.

Two tachykinin-related peptides (TRPs) are known in decapods, APSGFLGMRamide and TPSGFLGMRamide. The former peptide appears to be ubiquitously conserved in members of this taxon, while the latter has been suggested to be a genus (Cancer)- or infraorder (Brachyura)-specific isoform. Here, we characterized a cDNA from the American lobster Homarus americanus (infraorder Astacidea) that encodes both TRPs: six copies of APSGFLGMRamide and one of TPSGFLGMRamide.