Breeding system transitions in flowering plants and their genomic consequences – TRANS

The diversity and evolution of breeding systems have fascinated evolutionary biologists for long. They are very labile and can evolve rapidly, sometimes in response to human activities; furthermore, they have important evolutionary and ecological consequences. Understanding the causes and consequences of breeding system evolution is thus a central issue for understanding and better managing natural and cultivated populations. However, though ancient, some questions remain poorly explored or controversial: are there preferential transition pathways and do they vary between phylogenetic groups? Which are the genetic bases and the selective pressures involved in breeding system transitions? Which are the consequences of these transitions for genome evolution and species fate (e.g., are selfing and dioecy evolutionary dead-ends?). The increasing availability of breeding system information in many species, the possibility to obtain massive genomic data thanks to Next Generation Sequencing technologies, and the development of sophisticated modelling tools call for new investigations on these issues. In this project we propose to combine comparative phylogenetic approaches, population genetics modelling and genomic data analyses to address these issues. In a first part, we propose to build a breeding system database to analyse breeding system transitions in Angiosperms at various phylogenetic scales and to test for classical hypotheses about major evolutionary trends. In a second part, we propose to analyse in detail the dynamics of breeding system transitions by combining theoretical approaches, data analyses, and experimental work in three case studies: the transition from self-incompatibility to selfing in Arabidopsis, the evolution of gynodioecy and dioecy in Silene, and the evolution of androdioecy in Oleaceae. In the last part, we propose to investigate some genomic consequences of breeding system evolution, through theoretical approaches and genomic data analyses. This proposal unites most of the French community working on the evolution of the plant breeding systems with groups having complementary expertise (theory, population genetics, evolutionary genomics) from Montpellier, Lille, Lyon and Roscoff.