Dispersal across southern Iberian refugia? integrating RAPDs, sequence data and morphometrics inArmeria (plumbaginaceae)

Habitats with alkaline edaphic substrates are often associated with plant speciation and diversification. The tribe Alysseae, in the family Brassicaceae, epitomizes this evolutionary trend. In this lineage, some genera, like Hormathophylla, can serve as a good case for testing the evolutionary framework. This genus is centered in the western Mediterranean. It grows on different substrates, but mostly on alkaline soils. It has been suggested that diversification in many lineages of the tribe Alysseae and in the genus Hormathophylla is linked to a tolerance for high levels of Mg+2 in xeric environments. In this study, we investigated the controversial phylogenetic placement of Hormathophylla in the tribe, the generic limits and the evolutionary relationships between the species using ribosomal and plastid DNA sequences. We also examined the putative association between the evolution of different ploidy levels, trichome morphology and the type of substrates. Our analyses demonstrated the monophyly of the genus Hormathophylla including all previously described species. Nuclear sequences revealed two lineages that differ in basic chromosome numbers (x = 7 and x = 8 or derived 11, 15) and in their trichome morphology. Contrasting results with plastid genes indicates more complex relationships between these two lineages involving recent hybridization processes. We also found an association between chloroplast haplotypes and substrate, especially in populations growing on dolomites. Finally, our dated phylogeny demonstrates that the origin of the genus took place in the mid-Miocene, during the establishment of temporal land bridges between the Tethys and Paratethys seas, with a later diversification during the upper Pliocene.

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“…H . spinosa , has a larger distribution area, where lineages could refuge and re-establish gene flow during unfavorable periods [110–111].…”

Section: Discussionmentioning

confidence: 99%

Plant evolution in alkaline magnesium-rich soils: A phylogenetic study of the Mediterranean genus Hormathophylla (Cruciferae: Alysseae) based on nuclear and plastid sequences

et al. 2018

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“…In this sense, population genetic studies of Vulnerable taxa are highly recommended to identify minimum relevant genetic units for conservation (RGUCs, Ciofi et al 1999), which should be compatible with the maintenance of the evolutionary potential without interfering with the evolutionary history of the populations (Caujapé-Castells and Pedrola-Monfort 2004; Sánchez et al 2004;Pérez-Collazos et al 2008). This is particularly true for European taxa that inhabit high mountain areas and that have experienced different histories of population size contraction-expansion during the climatic changes of the Quaternary (Hewitt 1996(Hewitt , 2000Taberlet et al 1998;Stehlik 2000;Larena et al 2002Larena et al , 2006) that have conditioned their levels of genetic diversity and the phylogeographical relationships between populations (Vargas 2003). The knowledge of the relationships among populations is of primary interest because conservation genetics is biologically more meaningful if it accords with monophyletic groups (Moritz 1994;Soltis and Gitzendanner 1999).…”

Section: Discussionmentioning

confidence: 98%

The fewer and the better: prioritization of populations for conservation under limited resources, a genetic study with Borderea pyrenaica (Dioscoreaceae) in the Pyrenean National Park

Segarra‐Moragues

Catalán

2009

Genetica

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Taxa considered under low International Union for the Conservation of Nature categories of extinction risk often represent cases of concern to conservation biology. Their high relative abundance precludes management of the entire range due to limited economical resources. Therefore, they require a cost-effective management plan. Borderea pyrenaica (Dioscoreaceae), an endemic plant of the Central Pyrenees and pre-Pyrenees, reaches the French side of the Central Pyrenees on its narrow northernmost boundary at Gavarnie (Parc National des Pyrenées, PNP, France), where it is protected as Vulnerable and considered a priority species. We have used nuclear microsatellite population genetic data to design a management strategy for the 11 populations of B. pyrenaica present in this area and to identify Relevant Genetic Units for its Conservation. The 18 SSR loci analysed identified 56 alleles, 24 of which fulfilled the rarity criterion for this set of populations. Genetic structuring of populations and representativity values derived from regression analyses of probabilities of loss of rare alleles together support differentiation of the B. pyrenaica populations into different management units. Estimates derived from G(ST) values indicate that five populations would adequately represent the 99.9% of the variation relative to most common alleles whereas calculations based on representativity values indicated that these five populations should equate the proportion 2:2:1 from the three different phylogeographical subdivisions of Gavarnie (Western, Eastern-1 and Eastern-2 ranges). This scheme would allow the preservation of 98.21% of the total B. pyrenaica alleles present in Gavarnie, according to the post glacial history of its populations. This conservation genetic approach could be applied to other low-extinction risk categories of extremely rare and subalpine plants in need of regulatory plans in European National Parks and Natural Reserves.

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“…During these periods, genetic interchanges could have been enhanced by the existence of dolomitic substrates between the sierras. With such a spatially connected series of similar substrates and habitats, it is conceivable that westward (and eastward) migration has taken place following a stepping-stone mode (Gutiérrez Larena, Fuertes Aguilar & Nieto Feliner, 2006). The high interpopulational F ST values can probably be explained by the differentiation between populations during the current interglacial period.…”

Section: Response To the Climatic Fluctuations Of The Pleistocenementioning

confidence: 94%

Variability, genetic structure and phylogeography of the dolomitophilous speciesConvolvulus boissieri(Convolvulaceae) in the Baetic ranges, inferred from AFLPs, plastid DNA and ITS sequences

et al. 2014

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Convolvulus boissieri is an edaphic endemic plant which grows in the Baetic ranges always in association with high mountain xeric dolomitic outcrops. As these dolomitic areas appear in a 'soil-island' pattern, the distribution of this species is disjunct. Populations of this species frequently include a low number of individuals, which could have an important impact on their genetic diversity and viability. Convolvulus boissieri provides an excellent opportunity to study the genetic and phylogeographical aspects of species linked to dolomites. We used amplified fragment length polymorphism markers and nuclear (internal transcribed spacer region of the nuclear ribosomal cistron) and plastid sequences (trnL-trnF, rpl32-trnL and trnQ-5′rps16). Data were generated from 15 populations, representing the distribution area of the species. For sequence analysis and estimation of divergence times we also used sequences from other Convolvulus species. Results revealed low intrapopulational genetic diversity and a strong interpopulational structure. Furthermore, we found clear-cut differentiation caused by the existence of two large population groups separated by the Guadiana Menor river basin. Estimation of divergence times indicated that divergence took place during the Pleistocene glaciations. Genetic diversity and differentiation are similar to those other species exhibiting naturally fragmented distribution with a sky islands pattern. In phylogeographical terms, the successive glaciation-interglaciation cycles caused the species to spread from the western sites to eastern sites, the latter being more exposed to the effects of glaciation.

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Dispersal across southern Iberian refugia? integrating RAPDs, sequence data and morphometrics inArmeria (plumbaginaceae)

Cited by 7 publications

References 36 publications

Plant evolution in alkaline magnesium-rich soils: A phylogenetic study of the Mediterranean genus Hormathophylla (Cruciferae: Alysseae) based on nuclear and plastid sequences

Plant evolution in alkaline magnesium-rich soils: A phylogenetic study of the Mediterranean genus Hormathophylla (Cruciferae: Alysseae) based on nuclear and plastid sequences

The fewer and the better: prioritization of populations for conservation under limited resources, a genetic study with Borderea pyrenaica (Dioscoreaceae) in the Pyrenean National Park

Variability, genetic structure and phylogeography of the dolomitophilous speciesConvolvulus boissieri(Convolvulaceae) in the Baetic ranges, inferred from AFLPs, plastid DNA and ITS sequences

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