In investigating why the mutation they discovered caused disruption of fertilization in the mustard plant Arabidopsis, the scientists found that the pollen tubes did not burst when they came close to the female egg cells. So in the mutant plants, the sperm cells were not expelled from the pollen tubes toward the female cells. Instead the pollen tubes, in which the sperm reside, kept growing past the eggs cells.
The abstinence by mutual consent gene is the first gene identified so far with a critical function at the same time in both plant male and female reproductive cells that is essential for the delivery of sperm cells to the egg cell, said Boisson-Dernier.
The abstinence by mutual consent mutant pollen just acts as if there were no egg cell around and keeps on growing, Schroeder added. Its interesting because this lack of pollen bursting only happens if the mutation is carried by both the male and female, suggesting the abstinence by mutual consent gene somehow allows the male pollen and the female reproductive cells to talk to one another.
Boisson-Dernier found that the gene is responsible for producing a protein called peroxin that targets small organelles inside the cell called peroxisomes. Within the cell, peroxisomes are small organelles whose main functions are metabolizing fatty acids, protecting the cell from toxic free
|Contact: Kim McDonald|
University of California - San Diego