Biologists discover gene behind 'plant sex mystery'

Oct 22, 2008
The image shows two pollen grains viewed by fluorescence microscopy. A pair of red sperm cells are visible in the normal pollen grain (top left) whilst only one red germ cell is present in mutant pollen (bottom right). The sperm cells are visualized using the monomeric red fluorescent protein mRFP1 derived from a coral species. Credit: Lynette Brownfield and David Twell, University of Leicester

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 blocks promotes the production of a twin sperm cell cargo in each pollen grain and thus ensures successful reproduction in flowering plants.

"This discovery is a significant step forward in uncovering the mysteries of flowering plant reproduction. This new knowledge will be useful in understanding the evolutionary origins of flowering plant reproduction and may be used by plant breeders to control crossing behaviour in crop plants.

"In the future such information may become increasingly important as we strive to breed superior crops that maintain yield in a changing climate. Given that flowering plants dominate the vegetation of our planet and that we are bound to them for our survival, it is heartening that we are one step closer to understanding their reproductive secrets."

Researchers at the University of Leicester are continuing their investigation into plant reproduction. Further research underway in Professor Twell's laboratory is already beginning to reveal the answers to secrets about how the pair of sperm cells produced within each pollen grain aquires the ability to fertilize.

Source: University of Leicester

Explore further: Researchers collect soil samples from around the globe in effort to conduct fungi survey

add to favorites email to friend print save as pdf

Related Stories

Plants spice up their sex life with defensins

Jun 01, 2010

Since the beginning, plants and animals have deployed various mechanisms to fight pathogens. Proteins have always played an important part in this armoury, and a broad variety of defensin proteins have become part of the ...

Calcium and reproduction go together

Aug 22, 2014

Everyone's heard of the birds and the bees. But that old expression leaves out the flowers that are being fertilized. The fertilization process for flowering plants is particularly complex and requires extensive communication ...

Flower development in 3D: Timing is the key

Jul 14, 2014

In close collaboration with Jürg Schönenberger and Yannick Städler from the Department of Botany and Biodiversity Research of the Faculty of Life Sciences, University of Vienna, 14 developmental stages ...

Recommended for you

Parasitic worm genomes: largest-ever dataset released

7 hours ago

The largest collection of helminth genomic data ever assembled has been published in the new, open-access WormBase-ParaSite. Developed jointly by EMBL-EBI and the Wellcome Trust Sanger Institute, this new ...

Male sex organ distinguishes 30 millipede species

8 hours ago

The unique shapes of male sex organs have helped describe thirty new millipede species from the Great Western Woodlands in the Goldfields, the largest area of relatively undisturbed Mediterranean climate ...

How can we avoid kelp beds turning into barren grounds?

12 hours ago

Urchins are marine invertebrates that mould the biological richness of marine grounds. However, an excessive proliferation of urchins may also have severe ecological consequences on marine grounds as they ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.