PI: Patricia A. Bedinger (Colorado State University) Co-PIs: Bruce A. McClure (University of Missouri), Roger T. Chetelat (UC Davis), and Jocelyn Rose (Cornell University) Collaborators: Stephen Stack (Colorado State University) and Esther van der Knaap (Ohio State University)
The flowering plants are among the most successful organisms in terrestrial environments. Much of their success can be attributed to highly evolved mechanisms for controlling mating. These mechanisms help avoid inbreeding as well as interspecific matings that could result in sterility or other problems. Often, these mechanisms entail specific molecular-level interactions between the pollen (male) and pistil (female). Much progress has been made toward understanding mechanisms for preventing matings between closely related individuals such as between siblings; the pistil recognizes and rejects such pollen and thus, prevents inbreeding. However, the molecular basis of the more complex interactions between genetically dissimilar plants (i.e., different species) has long been intractable. Unresolved questions include: Where and when do reproductive barriers operate? What is the molecular nature of these barriers? Can these barriers be circumvented or created by the down-regulation or addition of specific genes? Genomic and proteomic tools combined with a long tradition of biological, genetic and biochemical studies of the tomato family now make it possible to address the mechanisms controlling interspecific pollination in new ways. This project will determine the developmental time and place of action of pollination barriers in the tomato family by direct observation of interspecific pollinations. The genes responsible for recognition and rejection of interspecific pollen [i.e., Interspecific Reproductive Barrier (IRB) genes] will be identified through proteomic analysis and mapping approaches made possible by tomato genomics projects. Finally, the function of candidate IRB genes in interspecific pollination will be determined by transforming them into new genetic backgrounds and testing for changes in pollination behavior.
Broader Impacts
The mechanisms controlling plant reproduction have major economic importance. For example, manipulation of reproductive processes is essential for the production of most hybrid crop plants. This project - to understand reproductive barriers between plant species - is directly relevant to regulating gene transfer between species, both desirable (transferring agronomically important traits from wild to domesticated species) and undesirable (transfer of transgenes from genetically modified crops into wild species). The project also expands genomics into biodiversity studies with the comparison of reproductive genes of domesticated and wild species. The project will make an important contribution to research infrastructure with the development of a new tool (the FISH Cassette for Mutagenesis) that will have wide application in genomics research. This project will also have a significant impact in terms of education. The development of a strong undergraduate training program at each host organization will be given high priority. In addition to one-on-one faculty mentored undergraduate research, a Many Minds component (incorporation of research into undergraduate lab courses) to the project will be developed at the both freshman and advanced undergraduate level. Data and biological resources generated by this project will be available through the project website, Interspecific Reproductive Barriers in Tomato (IRBT)(to be developed) and through the SOL Genomics Network (SGN) website (www.sgn.cornell.edu).
