Abstract
Self-incompatibility (SI) is widespread in flowering plants as a genetic system to prevent self-fertilization. We now know that SI is controlled by a single multi-allelic locus (named S-locus). In the Brassicaceae, SI is determined by the female determinant SRK (S-locus receptor kinase) expressing on stigmatic papilla cells and its ligand and the male determinant SP11 (S-locus protein 11) on the surface of pollen grains. When self-pollen attaches on the papilla cell surface, interaction between SRK and SP11 activates an SI signal to reject self-pollen. It is also known that SI can be overcome by supplying 4-5% CO2 gas, and this method has been effectively used on the large-scale production of parental inbred lines in F1-hybrid breeding. However, nearly nothing is known about the molecular mechanism of the SI breakdown system by the CO2 treatment.
In this study two inbred lines of Brassica rapa with different reaction level of SI to CO2 and their F1 and F2 progeny were used, looking for new insights into the SI overcome induced by the CO2 treatment. Our results indicate that the CO2 sensitivity is S-haplotype independent and further investigation is in progess.
