Grant: Research Tools and Instruments - Category 1 (<$150,000)

Many flowering plants have genetically controlled self-incompatibility (SI) systems that prevent a fertile hermaphroditic plant from self-fertilizing, thereby preventing the deleterious effects of inbreeding. Genetically controlled SI systems represent an impressive molecular cross-talk between male and female reproductive tissues: individuals typically contain two tightly linked genes, held together 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) cells. During reproduction, male and female gene products interact and when they recognize each other as being from same individual fertilization is prevented.  One of my main research goals is to characterize SI in the genus Campanula (Campanulaceae).  In previous research we showed that in C. rapunculoides, incompatible pollen tubes exhibit a decline in their rate of growth approximately 12 hours post-pollination. This point corresponds roughly to a switch from independent to dependent growth of the pollen tube and to the timing of the second mitotic division of the sperm nuclei. In this grant, we propose to expand our capacity to describe the events taking place during pollen-pistil interactions in C. rapunculoides and related taxa by requesting a specialized microscope camera and image analysis system to capture, edit, analysis and document our images. Since C. rapunculoides is an allopolyploid and SI is often modified in polyploids, we will also examine the nature of the SI response in its parental diploid progenitors. This will additionally involve karyotyping these species; the requested system is essential for this task. This research contributes important insights into pollen-pistil interactions in Campanula species and the role of polyploidy in the expression of SI. It is important to researchers studying the diversity and evolution of SI systems in the angiosperms; my lab being the main one to study SI in this large and diverse genus. Because many horticultural species are self-incompatible, the research has and will also contribute to the agricultural industry. It will also contribute to our understanding of the effect of population fragmentation on SI and breeding systems, important questions in the modern landscape.