Melting pot of biodiversity: first insights into the evolutionary patterns of the Colchic bramble flora (RubussubgenusRubus, Rosaceae)

Michal Sochor, Bohumil Trávníček
2016 Botanical journal of the Linnean Society  
The Caucasus is a biodiversity hotspot of global significance, containing a number of highly diverse and speciesrich plant taxa. The region is also thought to be an important evolutionary hotspot for Rubus subgenus Rubus (brambles). However, Caucasian brambles have only been poorly studied to date and our knowledge of their evolutionary mechanisms, systematics and taxonomic variability remains rudimentary. Therefore, the objectives of this study were to shed light on the evolution, diversity
more » ... reproduction modes of Rubus in one of the two Caucasian glacial refugia, Colchis. Flow cytometry measurements were used to estimate DNA ploidy, a flow cytometric seed screen was conducted to determine reproduction mode and Sanger sequencing of two non-coding plastid regions was used to reveal phylogenetic patterns. The most common ploidy level was tetraploid, followed by diploid and (rarely) triploid. Intra-individual variation in reproduction mode was low, as the morphoseries Glandulosi and Radula exhibited strict sexuality and other taxa were mostly apomictic. A few exceptions were observed that deserve further attention, e.g. sexuality induced hypothetically by haploid pollen or by environmental conditions, a high proportion of triploid embryos or polyspermy. Plastid haplotype variability revealed specific, ancient evolutionary patterns with limited involvement of extant diploid taxa and recent isolation from European brambles. We provide the first insight into the variability and evolution of Colchic brambles, which serves as a starting point for further systematic and evolutionary studies.
doi:10.1111/boj.12436 fatcat:w7vpslap7zfzbaiif76rl64tvi