Phylogenomic studies of Cardamine (Brassicaceae) provide new insights into the evolution and phylogeographic history of the Balkan mountain flora

Abstract

The Balkan Peninsula, a major biodiversity hotspot within the Mediterranean Basin, harbours a great proportion of endemic taxa. In this area, the genus Cardamine is represented by several endemic perennials confined to wet habitats. Using an integrative approach that combines next-generation sequencing (Hyb-Seq, RADseq), flow cytometric, cytogenetic, morphometric, and ecological niche analyses, we study several Cardamine species to shed more light on the evolution of hygrophytic flora in the mountains of the Balkan Peninsula and explain the factors that have shaped its current diversity and distribution patterns.

We focused on the taxonomically intricate species, C. barbaraeoides, which has been commonly confused with C. acris or C. amara. We revealed that it represents an allotetraploid stenoendemic species, confined to the Southern Pindos Mts. We resolved the phylogenetic relationships of the dip- loid relatives, which also supported biogeographic links between the Balkan and Anatolian-Caucasus regions. In the ongoing study, we are targeting diploid C. acris, a polymorphic species that grows in wet sites at high altitudes in several mountain ranges in the Balkan Peninsula. We aim to elucidate its phylogeographic history, which is likely to be influenced by range fragmentation and introgression with close relatives. Our studies highlight the evolutionary significance of mountain ranges in the

Balkan Peninsula, acting as both refugia and melting pots favouring species contacts, reticulate and polyploid evolution.

Acknowledgements. This work is supported by the research grants APVV-17-0616 (to K.M.) and

DoktoGrant APP0271 (to A.K.).