Estep , Matt C , Gowda, Bhavani , Huang, Kan , Timko, Michael , Bennetzen, Jeffrey .
Genomic characterization for parasitic weeds of the genus Striga by sample sequence analysis.
Generation of ~2200 Sanger sequence reads or ~10,000 454 sequence reads for seven Striga DNA samples allowed identification of the highly repetitive DNA content in these genomes. The fourteen most abundant repeats in these Striga species were identified and partially assembled. Annotation indicated that they represent eight long terminal repeat (LTR) retrotransposon families, three tandem satellite repeats, one LINE retroelement, and one DNA transposon. All of these repeats are most closely related to repetitive DNAs in other closely-related plants, and are not products of horizontal transfer from their host species. These repeats were differentially abundant in each species, with the LTR retrotransposons and satellite DNAs most responsible for variation in genome size. Each species had some repetitive elements that were more abundant and some less abundant than the other Striga species examined, indicating that no single element or any unilateral growth or decrease trend in genome behavior was responsible for variation in genome size and composition. Genome sizes were determined by flowsorting, and the values of 615 Mb (S.asiatica), 1330 Mb (S. gesnerioides),1425 Mb (S. hermonthica) and 2460 Mb (S. forbesii) suggest a ploidy series, a prediction supported by repetitive DNA sequence analysis. Phylogenetic analysis employing six chloroplast loci indicated the ancestral relationships of the five most agriculturally-important Striga species, with the unexpected result that the one parasite of dicotyledonous plants (S. gesnerioides) was found to be more closely related to some of the grass parasites than many of the grass parasites are to each other.
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1 - University of Missouri-St. Louis, Depatrment of Biology, R223 Research building, St. Louis, MO, 63121, USA
2 - University of Virginia, Depatrment of Biology, Charlottesville, VA, 22903, USA
3 - University of Georgia, Department of Genetics, Athens, GA, 30602, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Lindell C/Chase Park Plaza
Date: Wednesday, July 13th, 2011
Time: 11:15 AM