Grant: Discovery Grants Program - Individual

Over 100 families of flowering plants are estimated to have genetically controlled self-incompatibility (SI) systems. The presence of SI prevents a fertile hermaphroditic plant from self-fertilizing thereby preventing the deleterious effects of inbreeding. SI systems represent an impressive molecular cross-talk between male and female reproductive tissues. Individuals typically contain two tightly linked, highly variable genes at the S-locus; one of these is expressed in the male (pollen grain or pollen tube) and the other in the female (stigma or pistil) reproductive cells. During reproduction, male and female gene products interact and when their S-proteins match fertilization is prevented. My work addresses three main areas of SI research. Firstly, I have an on-going project to use classical and molecular approaches to determine the genetic basis of SI in the bellflower genus Campanula (Campanulaceae). We have recently identified candidate proteins for the female determinant of SI in C. rapunculoides and propose to continue the protein analyses and employ new molecular and experimental methods in our search. Secondly, I am interested in the effect of population structure on SI. Because self-fertilization may be selected in small or isolated populations, I propose experiments to study the role of population fragmentation on SI, fitness and connectivity among populations. Lastly, I use a variety of statistical methods to study the gain and loss of SI at the macro-phylogenetic level. In particular, I am interested in studying whether self-incompatible lineages have higher net diversification rates than self-compatible lineages. This project contributes fundamental knowledge to our understanding of the factors driving speciation and the incredible diversity of angiosperms over geological time: something Darwin referred to as "the abominable mystery". My overall research program contributes knowledge to basic research in pollen-pistil interactions and evolutionary genetics. It also contributes to applications in conservation biology examining the effect of fragmentation on plant reproduction and to applications in agriculture concerned with breeding programs for self-incompatible crops such as pear, cherries and apple.