PI: J. Christopher Pires (University of Missouri) Co-PIs: Christopher D. Town (The Institute for Genomic Research), Andrew H. Paterson (University of Georgia)
Brassica oleracea represents one of the most spectacular examples of plant morphological change brought about by human domestication and is emerging as a plant model in much the same manner that the dog is emerging as a model for mammal domestication. Domestication of most crops has resulted in enhancement of a single plant part for use by humans, such as the seeds of grains, the fruits of trees, or the roots of some vegetables. In contrast, B. oleracea has domesticated forms that have been selected for changes in several plant parts, including vegetative meristems (cabbages), stems (kohlrabi, marrowstem kale), leaf axils and leaves (Brussels sprouts, kales), and floral meristems (broccoli, cauliflower). Additional variation is found in close Brassica relatives, such as the leaves and roots of B. rapa morphotypes (Pak-choi, Chinese cabbage and root turnip) and high seed yields of oilseed B. rapa and B. napus, being developed for biofuels.
This extraordinary morphological diversity, together with its close relationship to Arabidopsis, makes B. oleracea an especially attractive system in which to elucidate fundamental biological processes. Genome sequence and associated resources will be developed to expedite molecular dissection of the morphological variation in B. oleracea, and contribute to a framework for investigating the relationship between this morphological variation and the structure and function of its genome. To better understand B. oleracea domestication, the project will also compare the ancient duplicated chromosomal regions of Brassica to the non-duplicated regions in Sisymbrium. Sisymbrium has been recently found to be much more closely related to Brassica than Arabidopsis.
A physical map of a self-compatible rapid-cycling model genotype of B. oleracea will be developed using high-coverage genomic library, and 30-35 corresponding genomic regions sequenced from Sisymbrium and B. oleracea. These sequences will be compared to each other and to B. rapa and Arabidopsis to shed new light on the pattern and tempo of genetic change in the Brassicaeae. These resources will lay the foundation for a worldwide community of researchers to dissect the genetic control of specific traits in B. oleracea as well as test hypotheses about the relationship between morphological change and genomic processes. Project activities are being coordinated with the Multinational Brassica Genome Project (www.brassica.info/).
The project will take advantage of the integration of Brassica into many classrooms through the long-standing use of Wisconsin rapid-cycling Brassica Fast Plants. An NSF GK-12 program and corresponding activities at University of Georgia will provide a testing ground for implementation of research-based educational materials.
Access to project outcomes The primary outcome of the project will be Bacterial Artificial Chromosome (BAC) and BAC-end sequences, which will be deposited in Genbank (www.ncbi.nlm.nih.gov/). The project web site, which will be accessible via www.plantgroup.org/cpires.html, will include annotated sequences as well as integrated genetic-cytomolecular maps.
