Symposium III: Advances in plant reproductive biology
Abs #
30001: Maintenance and loss of self-incompatibility in the crucifer family
The switch from out-crossing (allogamous) to self-fertilizing (autogamous) mating system is one of the most prevalent evolutionary trends in plant reproduction and an important mechanism of reproductive isolation in nature. Autogamy is thought to have evolved repeatedly as a result of selection for reproductive assurance when mating partners or pollinators are scarce, but little is known about the genetic events that underlie the evolution of inbreeding. The crucifer family provides ideal material for addressing this issue, because it includes several genera that are dimorphic for mating system. Furthermore, out-crossing in this family is due to the operation of a well-characterized self-incompatibility (SI) system, which is based on allele-specific interactions between highly polymorphic S locus-encoded receptor kinases (SRKs) and their cysteine-rich ligands (SCRs). The analysis and manipulation of inter-specific differences in mating system can reveal the evolutionary processes that produced mating system dimorphism in crucifers, and can also help elucidate the mechanism of self-recognition in the self-incompatibility response. We previously used comparative mapping studies and inter-specific complementation experiments to demonstrate that the switch to autogamy in Arabidopsis thaliana was due to inactivation of the SRK and SCR recognition genes. The results of similar studies being carried out in other crucifers and our progress towards understanding mating system maintenance and switching in the crucifer family will be presented.
