Pfeil, Bernard E. , Doyle, Jeff J. .
Evolutionary Dynamics of Resistance Genes in Soybean.
Some soybean (Glycine max) cultivars exhibit resistance to specific bacterial pathogens mediated by resistance genes (R-genes) at single loci. One of these genes, Rpg1-b, has been shown to confer resistance to Pseudomonas syringae, but has achieved this resistance independently via convergent evolution compared to the gene that confers this resistance in Arabidopsis thaliana. Rpg1-b is located in an R-gene rich region for which bacterial artificial chromosome (BAC) sequences are available. Analysis of these Glycine BAC sequences and BACs from a representative of its nearest generic relative (Teramnus labialis ) suggest that R-gene duplication has occurred several times before their divergence, and several times independently in both lineages after divergence. Despite a polyploid genome duplication in Glycine since it diverged from Teramnus, the R-gene duplications in Glycine do not fit a polyploid pattern, instead occurring on a local scale. The mechanisms and relative timing of R-gene duplication will be discussed.
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1 - Cornell University, L.H. Bailey Hortorium, Department of Plant Biology, Ithaca, New York, 14853, USA
Presentation Type: Oral Paper
Date: Monday, August 15th, 2005
Time: 2:45 PM