Candidate Genes for Ornamental Traits in Blueberry

Several genes are known to play major roles in controlling architectural and flowering traits of ornamental value. We are interested in screening germplasm collections to find allelic variation in these genes that could be used for breeding. Our long-term goal is to develop native plants with ornamental traits through an ecotilling approach with species indigenous to North America. This research was initiated with highbush blueberry (Vaccinium corymbosum), a natives species with a sequenced genome and an established germplasm collection. The draft genomic sequence of diploid V. corymbosum was searched for orthologs of four genes: (1) TFL1, which is involved in repetitive flowering, (2) AG, which plays a role in double-flowering, (3) GA20ox, which controls plant stature, and (4) BRC1, which is involved in shoot branching patterns. GenSAS was used to screen Roche 454-generated sequence scaffolds for homology to genes from tomato, tobacco, grape, and rhododendron. In species where the candidate gene was a member of a multi-gene family, the functionally dominant paralog was chosen for screening. Blueberry gene sequences were identified with blastx E-values that indicated significant similarity to TFL1 (<1e-26), AG (<1e-21), GA20ox (<1e-46), and BRC1 (<1e-37). The best match of blueberry sequences to benchmark genes was determined through ClustalW2 alignment. These sequences will be used to design PCR primers to amplify genes from accessions in the USDA blueberry germplasm collection, and allelic variation will be investigated.