Month: September 2022

SINGLE POLLEN TUBE SURVIVES. “In Arabidopsis, typically only a single pollen tube grows towards each ovule. Heterofertilization is likely extremely rare, as only about 1% of ovules attract two or more functional pollen tubes. These numbers indicate that various mechanisms exist in angiosperms to efficiently prevent polyspermy.” http://www.sciencedirect.com/science/article/pii/S1674205214608996 View in LinkedIn

INCEST BARRIERS. “As many as 50% of angiosperms also possess mechanisms to avoid self-fertilization by using SI to prevent inbreeding. SI provides mechanisms for self-recognition and rejection, and is specified by S-determinant genes at a highly polymorphic, multi-allelic S-locus. Thus, this is a key mechanism involving crosstalk between pollen and pistil.” http://www.sciencedirect.com/science/article/pii/S1674205214608996 View in LinkedIn

CROSSTALK MOLECULES. “Many of the crosstalk molecules identified to date represent various classes of secreted small proteins or peptides. In particular, the huge family of hundreds of CRPs, which has previously been shown to comprise proteins with essential roles in pathogen defense and symbiosis, has now emerged to contain key signaling factors in angiosperm reproduction.” http://www.sciencedirect.com/science/article/pii/S1674205214608996 View in LinkedIn

LIBRARY OF WORDS. “Other peptides/small proteins are also emerging as important players involved in pollen–pistil crosstalk. Peptides play also major roles during reproduction in animals and lower organisms, for example, acting as pheromones in gamete communication in Chlamydomonas and yeast.” http://www.sciencedirect.com/science/article/pii/S1674205214608996 View in LinkedIn

POLYMORPHIC WORDS. “A major advantage of using peptides for intercellular crosstalk is their polymorphism. A single amino acid exchange or modification can easily result in complete loss of binding capability at specific cell surface receptors. The specificity of crosstalk, thus, seems to be often mediated by the polymorphic small secreted protein/peptide ligands expressed by individual cell types. Studies to date have initiated the identification of small proteins that act as signaling ligands, together with some of their functions.” http://www.sciencedirect.com/science/article/pii/S1674205214608996 View in LinkedIn

IONIC WORDS. “More general signaling molecules involved in regulation of many of the pollination processes have also been identified. Ca2+ is now well established as playing a central role, acting in a signaling capacity during pollen germination, pollen tube growth, SI responses, and gamete reception.” http://www.sciencedirect.com/science/article/pii/S1674205214608996 View in LinkedIn

MESSENGER. “Ca2+ is important as an intracellular second messenger in the fertilization of many organisms. In animals including mouse, xenopus, ascidian, starfish and sea urchin, various patterns of cytosolic Ca2+ waves and oscillations are involved in fertilization and the subsequent onset of embryogenesis.” http://www.nature.com/articles/ncomms5722?WT.ec_id=NCOMMS-20140829 View in LinkedIn

WAVES OF MESSAGES. “Ca2+ waves and oscillation are key signalling elements during the fertilization process of animals, and are involved, for example, in egg activation. In the unique double fertilization process in flowering plants, both the egg cell and the neighbouring central cell fuse with a sperm cell each. Here we succeeded in imaging cytosolic Ca2+ in these two cells, and in the two synergid cells that accompany the gametes during semi-in vivo double fertilization.” http://www.nature.com/articles/ncomms5722?WT.ec_id=NCOMMS-20140829 View in LinkedIn

ELECTRICAL SIGNALS. “In animals like frogs and several marine invertebrates, polyspermy (the fertilization of an egg by two or more sperm cells) is prevented by an electrical charge across the surface of the egg (fast block in a few seconds) and/or by modification of the extracellular egg coat by a secretion reaction (slow block in dozens of seconds), following gamete fusion. A Ca2+ wave in the fertilized egg triggers the secretion reaction associated with the slow polyspermy block.” http://www.nature.com/articles/ncomms5722?WT.ec_id=NCOMMS-20140829 View in LinkedIn

SINGLE WINNERS. “In the flowering plants, the mechanism of polyspermy block is unknown. However, the phenomenon was recognized by in vitro fertilization analysis in maize about 20 years ago.” http://www.nature.com/articles/ncomms5722?WT.ec_id=NCOMMS-20140829 View in LinkedIn