Characterizing nrDNA ITS1, 5.8S and ITS2 secondary structures and their phylogenetic utility in the legume tribe Hedysareae with special reference to Hedysarum.

This is the first study to systematically evaluate rRNA secondary structures of Hedysareae with an emphasis on Hedysarum. ITS2 and 5.8S regions of the genus shared a common secondary structure with a four-fingered central loop, whereas ITS1 possessed five distinct structures. The secondary structural features of the two regions provided advantageous data for clades, species groups, and closely related species. Hemi-CBCs were mostly observed in the reconstruction of species groups, and Nsts, mostly between closely related species. The investigations showed that ITS1 varied more than ITS2 in length, GC content, and most of the diversity indices within the tribe. Maximum likelihood analyses of the synchronized sequence-structure tree of ITS1 were performed. The accuracy and phylogenetic signals of ITS1 were higher than ITS2. The similar GC content, and no CBC, in both spacers, fortified the close relationship of CEGO and H. sections Stracheya and Hedysarum clades in the synchronized sequence-structure tree topology of ITS1. In both regions, no inter-generic CBCs were detected inside the CEGO clade and the inter-sectional level of Hedysarum. But, in the ITS2 region, a CBC was detected between H. section Multicaulia, and Taverniera versus H. sections Hedysarum, and Stracheya. The lowest inter-sectional genetic distance and structural features were found between H. sect. Hedysarum and H. sect. Stracheya clades in the ITS2 region.

Endemics determine bioregionalization in the alpine zone of the Irano-Anatolian biodiversity hotspot (South-West Asia).

Alpine habitats are characterized by a high rate of range restricted species compared to those of lower elevations. This is also the case for the Irano-Anatolian global biodiversity hotspot in South-West Asia, which is a mountainous area harbouring a high amount of endemic species. Using two quantitative approaches, Endemicity Analysis and Network-Clustering, we want to identify areas of concordant species distribution patterns in the alpine zone of this region as well as to test the hypothesis that, given the high proportion of endemics among alpine species, delimitation of these areas is determined mainly by endemic alpine species, i.e., areas of concordant species distribution patterns are congruent with areas of endemism. Endemicity Analysis identified six areas of concordant species distribution patterns irrespective of dataset (total alpine species versus endemic alpine species), whereas the Network-Clustering approach identified five and four Bioregions from total alpine species and endemic alpine species, respectively. Most of these areas have been previously identified using the endemic flora of different elevational zones. The identified units using both methods and both datasets are strongly congruent, proposing that they reveal meaningful distribution patterns. Bioregionalization in the Irano-Anatolian biodiversity hotspot appears to be strongly influenced by the endemic alpine species, a pattern likely to hold in alpine regions outside the Irano-Anatolian hotspot. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00035-021-00266-7.