An enigma unique to flowering plants has been solved by researchers from the University of Leicester (UK) and POSTECH, South Korea.
The discovery is reported in the journal Nature on 23 October 2008.
Scientists already knew that flowering plants, unlike animals require not one, but two sperm cells for successful fertilisation.
The mystery of this 'double fertilization' process was how each single pollen grain could produce 'twin' sperm cells. One to join with the egg cell to produce the embryo, and the other to join with a second cell in the ovary to produce the endosperm, a nutrient-rich tissue, inside the seed.
Double fertilisation is essential for fertility and seed production in flowering plants so increased understanding of the process is important.
Now Professor David Twell, of the Department of Biology at the University of Leicester and Professor Hong Gil Nam of POSTECH, South Korea report the discovery of a gene that has a critical role in allowing precursor reproductive cells to divide to form twin sperm cells.
Professor Twell said: "This collaborative project has produced results that unlock a key element in a botanical puzzle.
The key discovery is that this gene, known as FBL17, is required to trigger the destruction of another protein that inhibits cell division. The FBL17 gene therefore acts as a switch within the young pollen grain to trigger precursor cells to divide into twin sperm cells.
"Plants with a mutated version of this gene produce pollen grains with a single sperm cell instead of the pair of sperm that are required for successful double fertilization.
"Interestingly, the process employed by plants to control sperm cell reproduction was found to make use of an ancient mechanism found in yeast and in animals involving the selective destruction of inhibitor proteins that otherwise block the path to cell division.
"Removal of these blo
|Contact: Professor David Twell|
University of Leicester