1. Self-Incompatibility in the Genus Arabidopsis: Characterization of the S Locus in the Outcrossing A. lyrata and Its Autogamous Relative A. thaliana
- Author
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Kusaba, Makoto, Dwyer, Kathleen, Hendershot, Jennifer, Vrebalov, Julia, Nasrallah, June B., and Nasrallah, Mikhail E.
- Subjects
Molecular Sequence Data ,Arabidopsis ,Brassica ,Plant Science ,Genes, Plant ,Polymerase Chain Reaction ,Species Specificity ,Gene Expression Regulation, Plant ,Sequence Homology, Nucleic Acid ,Amino Acid Sequence ,Crossing Over, Genetic ,Cloning, Molecular ,Gene Library ,Glycoproteins ,Plant Proteins ,Polymorphism, Genetic ,Base Sequence ,Sequence Homology, Amino Acid ,fungi ,food and beverages ,Chromosome Mapping ,Cell Biology ,Locus Control Region ,Recombinant Proteins ,Haplotypes ,Brassicaceae ,Pollen ,Protein Kinases ,Research Article - Abstract
As a starting point for a phylogenetic study of self-incompatibility (SI) in crucifers and to elucidate the genetic basis of transitions between outcrossing and self-fertilizing mating systems in this family, we investigated the SI system of Arabidopsis lyrata. A. lyrata is an outcrossing close relative of the self-fertile A. thaliana and is thought to have diverged from A. thaliana approximately 5 million years ago and from Brassica spp 15 to 20 million years ago. Analysis of two S (sterility) locus haplotypes demonstrates that the A. lyrata S locus contains tightly linked orthologs of the S locus receptor kinase (SRK) gene and the S locus cysteine-rich protein (SCR) gene, which are the determinants of SI specificity in stigma and pollen, respectively, but lacks an S locus glycoprotein gene. As described previously in Brassica, the S haplotypes of A. lyrata differ by the rearranged order of their genes and by their variable physical sizes. Comparative mapping of the A. lyrata and Brassica S loci indicates that the S locus of crucifers is a dynamic locus that has undergone several duplication events since the Arabidopsis--Brassica split and was translocated as a unit between two distant chromosomal locations during diversification of the two taxa. Furthermore, comparative analysis of the S locus region of A. lyrata and its homeolog in self-fertile A. thaliana identified orthologs of the SRK and SCR genes and demonstrated that self-compatibility in this species is associated with inactivation of SI specificity genes.
- Published
- 2001