Phylogeny and historical biogeography analysis support Caucasian and Mediterranean centres of origin of key holoparasitic Orobancheae (Orobanchaceae) lineages

Abstract

The extensive diversity of the tribe Orobancheae, the most species-rich lineage of holoparasitic Orobanchaceae, is concentrated in the Caucasus and Mediterranean regions of the Old World. This extant diversity has inspired hypotheses that these regions are also centres of origin of its key lineages, however the ability to test hypotheses has been limited by a lack of sampling and phylogenetic information about the species, especially in the Caucasus region. First, we assessed the phylogenetic relationships of several poorly known, problematic, or newly described species and host-races of four genera of Orobancheae occurring in the Caucasus region–Cistanche, Phelypaea, Phelipanche and Orobanche–using nuclear ribosomal (ITS) and plastid (trnL–trnF) sequence data. Then we applied a probablistic dispersal-extinction-cladogenesis model of historical biogeography across a more inclusive clade of holoparasites, to explicitly test hypotheses of Orobancheae diversification and historical biogeography shifts. In sum, we sampled 548 sequences (including 196 newly generated) from 13 genera, 140 species, and 175 taxa across 44 countries. We find that the Western Asia (particularly the Caucasus) and the Mediterranean are the centre of origin for large clades of holoparasitic Orobancheae within the last 6 million years. In the Caucasus, the centres of diversity are composed both of long-branch taxa and shallow, recently diversified clades, while Orobancheae diversity in the Mediterranean appears to represent mainly recent diversification.

Morphological diversity of pistil stigmas and its taxonomic significance of representatives of holoparasitic Orobanchaceae from Central Europe

“…In addition, our observations and measurements of stigmas were also compared with numerous photographs of analysed species, as well as with problematic sections, subsections and/or series of species from other parts of Europe and Asia. Our samples have also been presented in recent molecular phylogenetic studies (Piwowarczyk et al 2018(Piwowarczyk et al , 2021. The plant names were updated, based on the World Flora Online (WFO) (2022), as well as the Index of Orobanchaceae (Sánchez Pedraja et al 2016).…”

Orobanche ingens (Orobanchaceae) – a poorly known species of the Greater Caucasus: taxonomic problems, distribution, hosts and habitats

“… Speciosae because the species included here are both morphologically and genetically very similar to those of the subsect. Minores ( Piwowarczyk et al 2021 ). It is worth emphasising that individuals of O.…”

Phelypaea boissieri f. lutea (Orobanchaceae), a peculiar new form from Turkey and typification of the name of this species

“…in Iraq ( Sánchez Pedraja et al 2016 ; Piwowarczyk et al 2019 ). P. boissieri is molecularly, morphologically and regarding host preferences similar to P. coccinea ( Piwowarczyk et al 2019 , 2021 ). The morphological features that separate P. boissieri and P. coccinea are as follows: corolla - tube short and cup-shaped; corolla - lobes broadly obovateorbicular to orbicular, overlapping; anthers - hairy ( Stapf 1915 ; Nicolson 1975 ; Cullen 2010 ); however, sometimes apparently intermediate features are also observed ( Piwowarczyk et al 2019 ).…”

“…The morphological features that separate P. boissieri and P. coccinea are as follows: corolla - tube short and cup-shaped; corolla - lobes broadly obovateorbicular to orbicular, overlapping; anthers - hairy ( Stapf 1915 ; Nicolson 1975 ; Cullen 2010 ); however, sometimes apparently intermediate features are also observed ( Piwowarczyk et al 2019 ). Therefore, further research into the variability of P. boissieri and the inclusion of more samples for molecular analysis are required ( Piwowarczyk et al 2021 ).…”