Latitudinal environmental niches and riverine barriers shaped the phylogeography of the Central Chilean endemic Dioscorea humilis (Dioscoreaceae)

The effects of Pleistocene glaciations and geographical barriers on the phylogeographic patterns of lowland plant species in Mediterranean-climate areas of Central Chile are poorly understood. We used Dioscorea humilis (Dioscoreaceae), a dioecious geophyte extending 530 km from the Valparaíso to the Bío-Bío Regions, as a case study to disentangle the spatio-temporal evolution of populations in conjunction with latitudinal environmental changes since the Last Inter-Glacial (LIG) to the present. We used nuclear microsatellite loci, chloroplast (cpDNA) sequences and environmental niche modelling (ENM) to construct current and past scenarios from bioclimatic and geographical variables and to infer the evolutionary history of the taxa. We found strong genetic differentiation at nuclear microsatellite loci between the two subspecies of D. humilis, probably predating the LIG. Bayesian analyses of population structure revealed strong genetic differentiation of the widespread D. humilis subsp. humilis into northern and southern population groups, separated by the Maipo river. ENM revealed that the ecological niche differentiation of both groups have been maintained up to present times although their respective geographical distributions apparently fluctuated in concert with the climatic oscillations of the Last Glacial Maximum (LGM) and the Holocene. Genetic data revealed signatures of eastern and western postglacial expansion of the northern populations from the central Chilean depression, whereas the southern ones experienced a rapid southward expansion after the LGM. This study describes the complex evolutionary histories of lowland Mediterranean Chilean plants mediated by the summed effects of spatial isolation caused by riverine geographical barriers and the climatic changes of the Quaternary. Copyright: © 2014 Bischoff et al.Financial support for this study was provided by a Fundación BBVA BIOCON 05-093/06 project grant to PC and JGSM. JV was supported by a Fundación BBVA Ph.D. grant. JGSM was supported by two consecutive Spanish Aragón Government ‘‘Araid’’ and Spanish Ministry of Science and Innovation ‘‘Ramón y Cajal’’ postdoctoral contracts. PC was partially funded by a Bioflora (http://bifi.es/bioflora/) research team grant co-funded by the Spanish Aragón Government and the European Social Fund.Peer Reviewe

Population genetic structure of a sandstone specialist and a generalist heath species at two levels of sandstone patchiness across the Strait of Gibraltar

Many habitat specialist species are originally composed of small, discontinuous populations because their habitats are naturally fragmented or patchy. They may have suffered the long-term effects of natural patchiness. Mediterranean heathlands, a representative habitat in the Strait of Gibraltar region, are associated with nutrient-poor, acidic sandstone soils. Sandstone soil patches in the African side of the Strait (Tangier) are, in general, smaller and more scattered than in the European side (Algeciras). In this study, we analyze the effect of this sandstone patchiness on the population genetic diversity and structure of two Erica species from these Mediterranean heathlands that differ in their edaphic specificity, E. australis, sandstone specialist, and E. arborea, generalist. Average levels of within-population genetic diversity and gene flow between populations were significantly lower in Tangier (high sandstone patchiness) than in Algeciras (low patchiness) for the sandstone specialist, whereas no differences between both sides of the Strait were detected in the edaphic generalist. Since most endemic species in Mediterranean heathlands of the Strait of Gibraltar are sandstone specialists, these results highlight an increased vulnerability to loss of genetic diversity and local extinction of the heathland endemic flora in the Tangier side of the Strait of Gibraltar. © 2014 Gil-López et al.Project BREATHAL (CGL2011-28759/BOS) was financed by the Spanish Ministerio de Ciencia e Innovación.Peer Reviewe

Novel microsatellite loci for Sebaea aurea (Gentianaceae) and cross-amplification in related species.

[Premise of the study] Microsatellite loci were developed in Sebaea aurea (Gentianaceae) to investigate the functional role of diplostigmaty (i.e., the presence of additional stigmas along the style).[Methods and Results] One hundred seventy-four and 180 microsatellite loci were isolated through 454 shotgun sequencing of genomic and microsatellite-enriched DNA libraries, respectively. Sixteen polymorphic microsatellite loci were characterized, and 12 of them were selected to genotype individuals from two populations. Microsatellite amplifi cation was conducted in two multiplex groups, each containing six microsatellite loci. Cross-species amplifi cation was tested in seven other species of Sebaea . The 12 novel microsatellite loci amplifi ed only in the two most closely related species to S. aurea (i.e., S. ambigua and S. minutifl ora ) and were also polymorphic in these two species.[Conclusions] These results demonstrate the usefulness of this set of newly developed microsatellite loci to investigate the mating system and population genetic structure in S. aurea and related species.We acknowledge grants to J.K. from the Swiss National Science Foundation (PA00P3_129140) and the Velux Stiftung (project no. 679) and to J.G.S.-M. from a postdoctoral research contract “Ramón y Cajal” from the Ministerio de Ciencia e Innovación (MICINN), Spain.Peer Reviewe

Biogeography and evolution of seeder and resprouter forms of Erica coccinea (Ericaceae) in the fire-prone Cape fynbos

The genus Erica represents the epitome of plant biodiversity in the South African Cape fynbos with over 700 species. This genus is composed of seeder and resprouter species, but both species diversity and endemism are strongly linked to the seeder habit and concentrated in the southwestern Cape Floristic Region (CFR). Erica coccinea is a relatively abundant and widespread fynbos species whose most remarkable morphological feature is the existence of distinct seeder and resprouter forms, frequently—but not always—in disjunct populations. Both higher within- population genetic diversity and among-population differentiation have been found in seeders, most likely as a consequence of the shorter generation times and faster population turnovers. Resprouters, despite being less diverse, are suspected to be ancestral. However, no solid evidence has yet been provided for the ancestrality of the resprouter form, or for the demographic processes that have determined the current distribution of genetic diversity in both regeneration forms. Here, we used microsatellites and sequences of the nuclear ribosomal internal transcribed spacers to describe the phylogeographic structure of seeder and resprouter E. c occinea populations and provide good evidence for the ancestral status of the resprouter form and the comparatively high rates of molecular evolution in derived seeder populations. We also reveal that mixed populations, where both seeder and resprouter individuals co-occur, were originated by secondary contacts. This study highlights the role of fire in driving accelerated diversification in seeder lineages of highly speciose CFR fynbos taxa

Diversidad y Evolución de Riella, un género de hepáticas emblemático de ambientes acuáticos halófilos estacionales

Ponencia presentada en el V Seminario Internacional, Gestión y Conservación de la Biodiversidad celebrado en Almería del 4 al 8 de abril de 2011Peer Reviewe

Isolation and characterisation of di and tri nucleotide microsatellite loci in Rosmarinus officinalis (Lamiaceae), using enriched genomic libraries

5 paginas, 2 tablas.An enrichment protocol was used to isolate and characterise microsatellite loci in Rosmarinus officinalis, a Mediterranean chamephyte. Twelve microsatellite loci were characterised and amplified a total of 117 alleles in a sample of 30 individuals from one population, with an average of 9.75 alleles per locus. Observed heterozygosities ranged from 0.333 to 0.900. Cross-species transferability was also assayed in the two other species of the genus. The cumulated probabilities of exclusion for paternity and parentage of the 12 loci were of 0.999971 and 1, respectively, supporting the usefulness of these microsatellite loci for parentage analyses. Nine out of 12 microsatellite loci amplified in the two species and were polymorphic detecting a total of 49 and 45 in R. eriocalyx and R. tomentosus, respectively. Twenty-two alleles were exclusive of R. eriocalyx and 12 of R. tomentosus, additionally, three alleles were shared between these two species but were otherwise absent in the analysed individuals of R. officinalis. In total, this set of markers amplified 154 different microsatellite alleles, supporting their usefulness to conduct population genetic, reproductive biology and hybridisation studies in Rosmarinus.We thank Dr. M. Palop-Esteban for her help during sampling and Prof. J.F. Mota (University of Almería, Spain) for providing samples of R. eriocalyx. This study has been supported by a Project grant "Ayudas para la realización de proyectos de I+D+i para equipos de investigación emergentes o de reciente creación (Ref. GV/2007/259)" from the Conselleria d’Empresa, Universitat i Ciencia, Generalitat Valenciana. J. G. Segarra-Moragues was supported by a Itinerario Integrado de Inserción Profesional (I3P) postdoctoral grant from the Spanish Consejo Superior de Investigaciones Científicas (CSIC) and G. Gleiser was supported by a FPU PhD grant from the Spanish Ministerio de Educación y Ciencia.Peer reviewe

Characterization of microsatellite loci in Festuca gautieri (Poaceae) and transferability to F. eskia and F. xpicoeuropeana

3 páginas, 2 tablas.Premise of the study: Enriched genomic libraries were used to isolate and characterize microsatellite loci in Festuca gautieri, an important plant component of subalpine calcareous grasslands of the eastern Iberian Peninsula, the Pyrenees, and the Cantabrian Mountains. Microsatellites were required to investigate landscape genetics across its distribution range and at a narrower geographical scale within the Ordesa y Monte Perdido, Aiguestortes, and Picos de Europa Spanish national parks.Peer reviewe

Riella bialata Trab. (Riellaceae, Marchantiophyta): A new addition to the European liverwort flora

[EN] Riella (Riellaceae, Sphaerocarpales) is a genus of aquatic liverworts with a disjunct worldwide distribution in areas of seasonal Mediterranean-type climates. Its centre of diversity is located in the Mediterranean basin, where about half the species number of the genus is concentrated. In the course of a worldwide revision of the genus Riella, plants from a monoicous species with wingless, not papillose and smooth involucres were found in two distant Iberian localities. These plants showed a geminate dorsal wing, unlike the single wing occurring in the remaining species of the genus. This character unambiguously assigns these populations to R. bialata, a species known to date from a single collection in its Algerian type locality. Riella bialata is thus reported as new to Europe. Fresh materials enabled detailed morphological analyses, and the Iberian materials are extensively described and illustrated herein.[FR] Riella (Riellaceae, Sphaerocarpales) est un genre d'hépatiques aquatiques avec une répartition disjointe dans le monde entier dans les domaines de climat méditerranéen. Son centre de diversité se trouve dans le bassin méditerranéen qui concentre environ la moitié des espèces du genre. Au cours d'une révision mondiale du genre Riella, des plantes d'une espèce monoïque avec des involucres dépourvus d'ailes, non papilleux, lisses ont été trouvées dans deux localités ibériques lointaines. Ces plantes ont une aile dorsale géminée, contrairement à l'aile isolée qui caractérise les autres espèces du genre. Ce caractère affiche sans ambiguïté ces populations à R. bialata, une espèce jusqu'ici connue à partir d'une collection unique de sa localité type algérienne. Riella bialata est donc signalée comme nouvelle pour l'Europe. Des matériaux frais ont été utilisés pour des analyses morphologiques détaillées et les matériaux ibériques sont ici amplement décrits et illustrés.Peer Reviewe

Glacial survival, phylogeography, and a comparison of microsatellite evolution models for resolving population structure in two species of dwarf yams (Borderea, Dioscoreaceae) endemic to the central Pyrenees

16 paginas, 5 figuras, 4 tablas.Background: Borderea is a relict genus in the Pyrenees comprising only two extant allopolyploid species. The pre-Pyrenean, cliff-dweller B. chouardii is confined to a single critically endangered population, whereas the subalpine B. pyrenaica is more widely distributed in the mobile scree-habitats of the central Pyrenees and pre-Pyrenees. Aims: To determine the genetic structure and relationships among individuals and populations of both taxa to understand their origin. To compare two alternative evolutionary models, the Infinite Allele Model (IAM) and the Stepwise Mutation Model (SMM), in an examination of the primary factors responsible for population divergence during the Quaternary. Methods: A survey of nuclear microsatellite (Simple Sequence Repeat, SSR) variation was conducted to infer relationships among allelic phenotypes and genotypes and to evaluate the relative contributions of migration and mutation to population genetic structure. Results: The occurrence of shared ancestral alleles among populations of both Borderea species supported a presumably late-Tertiary divergence of the species in the low-altitudinal pre-Pyrenees. Borderea chouardii exhibited strong genetic differentiation between two sub-populations separated by only 150 m of vertical distance. In B. pyrenaica, populations from the pre-Pyrenees and southern Pyrenees showed greater genetic differentiation and more allelic diversity relative to populations from the northern Pyrenees. Conclusions: These results suggest that B. pyrenaica experienced glacial survival in warm southern pre-Pyrenean refugia followed by rapid postglacial migration towards the northern Pyrenees. Despite the a priori high suitability of the SMM for microsatellite markers, genotypic relationships among individuals and populations and genotypic assignments to predefined groups of B. pyrenaica were always better resolved by the IAM than by the SMM. This points towards the overwhelming influence of migration and genetic drift over mutation in the Quaternary history of the B. pyrenaica populations. However, for B. chouardii a similar pattern was shown by both evolutionary models, suggesting that sub-population divergence of this species could have also been favoured by mutation.We are indebted to Prof. R.J. Abbott and two anonymous referees for their valuable comments that have greatly improved the quality of the manuscript. We are also grateful to the authorities of the Spanish Government of Aragón and the French National Park of the Pyrenees for allowing sampling of Borderea populations and for previous financial support. This work was supported by the Spanish Fundación BBVA grant BIOCON05/093. JGSM was also supported from an Agencia Aragonesa para la Invesigación y el Desarrollo (ARAID) postdoctoral contract.Peer reviewe