Heterostyly and the evolution of mating system in plants

Many organisms exhibit various strategies to avoid self-fertilization and promote outcrossing (mating with different individuals). Such strategies have repeatedly evolved and been disrupted throughout evolution, resulting in a remarkable diversity of mating systems. The most well-known strategy is sexual dimorphism, in which mating is only successful between opposite sexes (e.g. male and female) which exhibit different morphology (e.g. males and females look different). However, some plants, including buckwheat that I have been studying, have evolved a strategy where all individuals either have flowers with long or short styles (female organ), referred to as heterostyly or distyly, and mating is typically only successful between individuals with long-styled flowers and those with short-styled flowers, i.e., outcrossing is promoted by floral dimorphism that is not associated with sexes. While how such a system evolves and its genetic basis are still largely unknown, the genomic region responsible for heterostyly has been identified in many different species within the past year or two, revealing some interesting parallels between independently evolved systems. In this seminar, I will introduce these recent findings and discuss how heterostyly may be linked to the diverse mating systems observed in plants. I will also introduce what we have been doing and are planning/hoping to do in buckwheat and its related species.