SUNFLOWER GERMPLASM DIVERSIFICATION AND CHARACTERIZATION UTILIZING WILD SUNFLOWER SPECIES, CYTOGENETICS, AND APPLIED GENOMICS
Location: Sunflower Research
Title: Development of a Set of Chromosome-Specific Cytogenetic DNA Markers in Sunflower Using BAC-FISH
Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: March 12, 2009
Publication Date: March 13, 2009
Citation: Feng, J., Liu, Z., Jan, C. 2009. Development of a Set of Chromosome-Specific Cytogenetic DNA Markers in Sunflower Using BAC-FISH. Proceedings 31st Sunflower Research Workshop, National Sunflower Association, January 13-14, 2009, Fargo, ND. Available: http://www.sunflowernsa.com/research/research-workshop/documents/Feng_BACFISH_09.pdf
Interpretive Summary: Karyotpye analyses of sunflower have been reported by different authors either using traditional chromosome banding or in conjunction with in situ hybridization of rDNA Various genetic linkage maps, such as RFLP and SSR, have been established for sunflower. However, the relationship between genetic linkage groups and individual chromosomes of sunflower remains unknown. Our previous work established an RFLP linkage map consisting of 20 linkage groups along with two BAC and BIBAC libraries that were constructed from the cultivated line HA 89. A set of linkage group-specific BAC/BIBAC clones have been identified from the libraries by using the mapped RFLP markers. The objective of this study was to identify a set of chromosome-specific BAC clones and physically assign each to a specific sunflower chromosome.
In diploid sunflower (2n=34), conventional karyotypes and various genetic linkage maps have been established. However, the relationship between genetic linkage groups and individual chromosomes of sunflower remains unknown. Recently, a set of linkage group-specific BAC and BIBAC clones were identified from two complementary BAC and BIBAC libraries constructed for cultivated sunflower cv. HA 89. In the present study, we used this set of linkage group-specific clones (~100kb) as probes to hybridize to HA 89 mitotic metaphase chromosomes through the BAC-FISH technique. Because most BAC/BIBAC clones contain numerous repetitive sequences, a high ratio of blocking DNA (HA 89) to probe DNA was applied to hybridization reactions to minimize background signals. As a result, all sunflower chromosomes were anchored by one or two BAC/BIBAC clones with distinctive FISH signals. FISH analysis based on tandemly repetitive sequences, such as rDNA, has been reported in sunflower. However, the BAC-FISH technique developed here using low-copy BAC/BIBAC clones is the first report for sunflower.