title: Genetics, evolution, and adaptive significance of the selfing syndrome in the genus Capsella.
abstract: The change from outbreeding to selfing is one of the most frequent evolutionary transitions in flowering plants. It is often accompanied by characteristic morphological and functional changes to the flowers (the selfing syndrome), including reduced flower size and opening. Little is known about the developmental and genetic basis of the selfing syndrome, as well as its adaptive significance. Here, we address these issues using the two closely related species Capsella grandiflora (the ancestral outbreeder) and red shepherd's purse (Capsella rubella, the derived selfer). In C. rubella, petal size has been decreased by shortening the period of proliferative growth. Using interspecific recombinant inbred lines, we show that differences in petal size and flower opening between the two species each have a complex genetic basis involving allelic differences at multiple loci. An intraspecific cross within C. rubella suggests that flower size and opening have been decreased in the C. rubella lineage before its extensive geographical spread. Lastly, by generating plants that likely resemble the earliest ancestors of the C. rubella lineage, we provide evidence that evolution of the selfing syndrome was at least partly driven by selection for efficient self-pollination. Thus, our studies pave the way for a molecular dissection of selfing-syndrome evolution.
authors.affiliation: Institut für Biochemie und Biologie, Universität Potsdam, D-14476 Potsdam-Golm, Germany.
authors.forename: Adrien
authors.initials: A
authors.lastname: Sicard
authors.forename: Nicola
authors.initials: N
authors.lastname: Stacey
authors.forename: Katrin
authors.initials: K
authors.lastname: Hermann
authors.forename: Jimmy
authors.initials: J
authors.lastname: Dessoly
authors.forename: Barbara
authors.initials: B
authors.lastname: Neuffer
authors.forename: Isabel
authors.initials: I
authors.lastname: Bäurle
authors.forename: Michael
authors.initials: M
authors.lastname: Lenhard
mesh_terms: D000220:Adaptation, Biological / Q000235:genetics*; D000483:Alleles; D005075:Biological Evolution; D029687:Capsella / Q000235:genetics* / Q000254:growth & development; D002678:Chimera / Q000235:genetics; D002874:Chromosome Mapping; D018744:DNA, Plant / Q000235:genetics; D035264:Flowers / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development; D005843:Geography; D054817:Pollination / Q000235:genetics*; D040641:Quantitative Trait Loci; D017422:Sequence Analysis, DNA
chemical_list: D018744:DNA, Plant