Molecular Ecology and Evolution
Potter, Daniel , Tsukamoto, Tatsuya , Chin, Siew Wai , Iezzoni, Amy F. .
Phylogeny of self-incompatibility genes in Prunus (Rosaceae).
In Rosaceae, Plantaginaceae, and Solanaceae, gametophytic self-incompatibility (GSI) is mediated by a stylar component known to be an S-RNase and its genetically linked pollen component known to be an F-box protein. In Petunia, Antirrhinum, and Malus, the pollen S-determinant gene has been named SLF, while in Prunus the S-RNase linked F-box protein gene that shows appropriate levels of allelic diversity has been termed SFB. Relationships between SLF, SFB, and other F-box protein genes have not been clearly resolved. In order to elucidate origins and patterns of evolution of GSI in Prunus, we undertook phylogenetic analyses of genes encoding SLF, SFB, and related non-S F-box proteins from several angiosperm families, and of S-RNase genes from Rosaceae, Solanaceae, and Plataginaceae, with Prunus represented in all analyses by multiple S-haplotypes from five species. Our analyses produced three principal results. 1) Our F-box protein gene phylogenies suggest that the evolution of GSI in Prunus involved recruitment of a different pollen determinant than the one proposed in Malus and the other two families and that the gene duplication that led to the divergence of SFB from SLF occurred sometime during the evolution of eudicots prior to the divergence of rosids from asterids. 2) Within Prunus, phylogenies of S-RNase and of SLF/SFB show no correspondence to well supported species phylogenies, but the Prunus sequences are resolved as distinct from those of Malus and Pyrus, suggesting that in Rosaceae, coalescence of the genes encoding both the stylar and the pollen determinants of GSI has occurred at the generic or tribal level. 3) Within Prunus, significant incongruence between SFB and S-RNase data sets indicates that the phylogenetic histories of the two genes are different and that they have not evolved in a tightly linked coevolutionary pattern, suggesting that recombination has been involved in the generation of new S-haplotypes.
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1 - University of California, Davis, Department of Plant Sciences, Mail Stop 2, One Shields Avenue, Davis, CA, 95616, USA
2 - University of Arizona, Department of Plant Sciences, 303 Forbes Building, Tucson, AZ, 85721-0036, USA
3 - Michigan State University, Department of Horticulture, East Lansing, MI, 48824, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Boulevard B/Hilton
Date: Wednesday, July 11th, 2007
Time: 1:30 PM