Silene, a versatile model system: from sex and genome evolution to ecology and speciation

Fundamental and applied research in evolutionary biology benefits from the use of model systems in which approaches from disparate disciplines can be integrated. Here, we review recent progress in evolutionary research on the long-standing model system Silene, a large genus with a well-resolved phylogeny and newly available, expanded genomic resources. We report how studies using Silene have pioneered advances in the understanding of the structure and function of sex chromosomes and the rapid evolution of plant organelles. Silene was instrumental for elucidating the causes and consequences of shifts in sexual systems, in particular between gynodioecy and dioecy. Investigations of Silene species and associated anther-smut fungi have further led to major insights into host specialization and coevolution in plant-pathogen systems. Moreover, Silene has recently developed into a promising model system for the understanding of evolutionary responses to abiotic conditions, of pollinator-mediated evolution of flower advertising traits and of the drivers of speciation. We outline open questions for which the Silene system is particularly suitable, including the use of previously underexplored comparative approaches.