Characterization and conservation of the personal herbarium of Llorenç Garcias Font (PH-GARC), placed in trust at the Natural History Society of the Balearic Islands (SHNB)

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Patterns of genetic variability and habitat occupancy in Crepis triasii (Asteraceae) at different spatial scales: insights on evolutionary processes leading to diversification in continental islands

Background and AimsArchipelagos are unique systems for studying evolutionary processes promoting diversification and speciation. The islands of the Mediterranean basin are major areas of plant richness, including a high proportion of narrow endemics. Many endemic plants are currently found in rocky habitats, showing varying patterns of habitat occupancy at different spatial scales throughout their range. The aim of the present study was to understand the impact of varying patterns of population distribution on genetic diversity and structure to shed light on demographic and evolutionary processes leading to population diversification in Crepis triasii, an endemic plant from the eastern Balearic Islands.MethodsUsing allozyme and chloroplast markers, we related patterns of genetic structure and diversity to those of habitat occupancy at a regional (between islands and among populations within islands) and landscape (population size and connectivity) scale.Key ResultsGenetic diversity was highly structured both at the regional and at the landscape level, and was positively correlated with population connectivity in the landscape. Populations located in small isolated mountains and coastal areas, with restricted patterns of regional occupancy, were genetically less diverse and much more differentiated. In addition, more isolated populations had stronger fine-scale genetic structure than well-connected ones. Changes in habitat availability and quality arising from marine transgressions during the Quaternary, as well as progressive fragmentation associated with the aridification of the climate since the last glaciation, are the most plausible factors leading to the observed patterns of genetic diversity and structure.ConclusionsOur results emphasize the importance of gene flow in preventing genetic erosion and maintaining the evolutionary potential of populations. They also agree with recent studies highlighting the importance of restricted gene flow and genetic drift as drivers of plant evolution in Mediterranean continental islands

Deciduous and evergreen oaks show contrasting adaptive responses in leaf mass per area across environments

• Increases in leaf mass per area (LMA) are commonly observed in response to environmental stresses and are achieved through increases in leaf thickness and/or leaf density. Here, we investigated how the two underlying components of LMA differ in relation to species native climates and phylogeny, across deciduous and evergreen species. • Using a phylogenetic approach, we quantified anatomical, compositional and climatic variables from 40 deciduous and 45 evergreen Quercus species from across the Northern Hemisphere growing in a common garden. • Deciduous from shorter growing seasons tended to have leaves with lower LMA and leaf thickness than those from longer growing seasons, while the opposite pattern was found for evergreens. For both habits, LMA and thickness increased in arid environments. However, this shift was associated with increased leaf density in evergreens but reduced density in deciduous species. • Deciduous and evergreen oaks showed fundamental leaf morphological differences that revealed a diverse adaptive response. While LMA in deciduous may diversified in tight coordination with thickness mainly modulated by aridity, diversification of LMA within evergreens appears dependent on the infrageneric group, with diversification in leaf thickness modulated by both aridity and cold, while diversification in leaf density only modulated by aridity.Publishe

Positively selected amino acid replacements within the RuBisCO enzyme of oak trees are associated with ecological adaptations

Phylogenetic analysis by maximum likelihood (PAML) has become the standard approach to study positive selection at the molecular level, but other methods may provide complementary ways to identify amino acid replacements associated with particular conditions. Here, we compare results of the decision tree (DT) model method with ones of PAML using the key photosynthetic enzyme RuBisCO as a model system to study molecular adaptation to particular ecological conditions in oaks (Quercus). We sequenced the chloroplast rbcL gene encoding RuBisCO large subunit in 158 Quercus species, covering about a third of the global genus diversity. It has been hypothesized that RuBisCO has evolved differentially depending on the environmental conditions and leaf traits governing internal gas diffusion patterns. Here, we show, using PAML, that amino acid replacements at the residue positions 95, 145, 251, 262 and 328 of the RuBisCO large subunit have been the subject of positive selection along particular Quercus lineages associated with the leaf traits and climate characteristics. In parallel, the DT model identified amino acid replacements at sites 95, 219, 262 and 328 being associated with the leaf traits and climate characteristics, exhibiting partial overlap with the results obtained using PAML

Estudio filogeográfico de especies vegetales del Mediterráneo occidental

[spa] La presente tesis doctoral pretende contribuir al esclarecimiento de los patrones filogeográficos de plantas estenócoras del Mediterráneo occidental mediante el análisis espacial de los genotipos de ADN cloroplástico (raramente ADN nuclear) detectados mediante técnicas de secuenciación. Las regiones diana utilizadas son los espaciadores intergénicos trnT-trn L y trn L- trn F, así como el intrón presente en el trn L, las cuales han proporcionado suficientes niveles de diversidad para distinguir polimorfismos intraespecíficos en todas las especies analizadas. Se pretende analizar los niveles de diversidad haplotípica en una especie de distribución Mediterránea, centrada en la cuenca occidental (Buxus balearica Lam.), dos especies de distribución tirrénica (Naufraga balearica Constance & Cannon y Thymus herba-barona Loisel.), y seis endemismos de Baleares (Thymelaea velutina (Camb) Endl., Hippocrepis balearica Jacq., H. grosii (Pau) Boira et al., Senecio rodriguezii Willk., Erodium reichardii Murray, Polycarpon colomense Porta, y Ononis crispa L.) con el fin de dilucidar: (i) la existencia de patrones filogeográficos comunes, (ii) el nivel de diversidad genética presente en especies insulares de islas continentales, (iii) las hipotéticas rutas de migración poblacional detectables dentro de y entre islas, (iv) la existencia de barreras biogeográficas entre las islas Baleares orientales (Mallorca, Menorca y Cabrera), y (v) la relación entre mecanismos de dispersión y estructuración filogeográfica

A phylogeographic split in Buxus balearica (Buxaceae) as evidenced by nuclear ribosomal markers: When ITS paralogues are welcome

Sequences from the ribosomal nuclear internal transcribed spacers (ITS) have been widely used to infer evolutionary hypotheses across a broad range of living organisms. Intraspecific sequence variation is assumed to be absent or negliable in most species, but few detailed studies have been conducted to assess the apportionment of ITS sequence variation within and between plant populations. Buxus balearica was chosen as a model species to assess the levels of infraspecific and intragenomic ITS variation in rare and endangered species occurring in disjunct populations around the Mediterranean basin. Intragenomic polymorphic sites were detected for western and eastern accessions of B. balearica and in two accessions of the sister species B. sempervirens. Overall, 19 different ribotypes were found in B. balearica after sequencing 48 clones, whereas 15 ribotypes were detected in 19 clones of B. sempervirens. The integrity and secondary structure stability of the ribosomal sequences suggest that they are not pseudogenes. The high number of ribotypes recovered through cloning suggested that some sequences could be chimeric or generated in vivo by partial homogenization through gene conversion or unequal crossing-over. Average sequence divergence among B. balearica clones was 0.768%, and the most divergent sequences differed by 1.62%. Available evidence does not suggest that B. balearica paralogues have been obtained from other extant Buxus species through interspecific hybridization. The presence of several ribosomal sequences in box implies that the molecular forces driving the concerted evolution of this multigene family are not fully operational in this genus. Phylogenetic analyses of cloned ITS sequences from B. balearica displayed very poor resolution and only two clades received moderate bootstrap support. Despite the marked intragenomic sequence divergence found, ribosomal data suggest a clear phylogeographic split in B. balearica between western and eastern accessions. The distinct, nonchimeric sequences that are postulated as being present in each biogeographic group suggest that box populations from Anatolia (eastern Mediterranean) are relict. © 2007 Springer Science+Business Media, Inc.This work was partially funded by projects BOS2001-0610, REN2011-3506-C02-01, and MMA 034/2002. A.L. was supported by a FPU fellowship (Spanish Ministry of Education, MECD)Peer Reviewe

Improving the estimation of mesophyll conductance to CO2: on the role of electron transport rate correction and respiration

Mesophyll conductance (g m ) can markedly limit photosynthetic CO2 assimilation and is required to estimate the parameters of the Farquhar–von Caemmerer–Berry (FvCB) model properly. The variable J (electron transport rate) is the most frequently used method for estimating g m, and the correct determination of J is one of its requirements. Recent evidence has shown that calibrating J can lead to some errors in estimating g m , but to what extent the parameterization of the FvCB model is affected by calibrations is not well known. In addition to determining the FvCB parameters, variants of the J calibration method were tested to address whether varying CO 2 or light levels, possible alternative electron sinks, or contrasting leaf structural properties might play a role in determining differences in αβ, the product of the leaf absorptance (α) and the photosystem II optical cross-section (β). It was shown that differences in αβ were mainly attributed to the use of A/C i or A/PPFD curves to calibrate J. The different αβ values greatly influenced g m , leading to a high number of unrealistic values in addition to affecting the estimates of the FvCB model parameters. A new approach was devised to retrieve leaf respiration in the light from combined A/C i and A/C c curves and a framework to understand the high variation in observed g m values. Overall, a background is provided to decrease the noise in g m , facilitating data reporting and allowing better retrieval of the information presented in A/C i and A/C c curves

Data from: Weak coordination between leaf structure and function among closely related tomato species

Theory predicts that natural selection should favor coordination between leaf physiology, biochemistry and anatomical structure along a functional trait spectrum from fast, resource-acquisitive syndromes to slow, resource-conservative syndromes. However, the coordination hypothesis has rarely been tested at a phylogenetic scale most relevant for understanding rapid adaptation in the recent past or for the prediction of evolutionary trajectories in response to climate change. We used a common garden to examine genetically based coordination between leaf traits across 19 wild and cultivated tomato taxa. We found weak integration between leaf structure (e.g. leaf mass per area) and physiological function (photosynthetic rate, biochemical capacity and CO2 diffusion), even though all were arrayed in the predicted direction along a ‘fast–slow’ spectrum. This suggests considerable scope for unique trait combinations to evolve in response to new environments or in crop breeding. In particular, we found that partially independent variation in stomatal and mesophyll conductance may allow a plant to improve water-use efficiency without necessarily sacrificing maximum photosynthetic rates. Our study does not imply that functional trait spectra, such as the leaf economics spectrum, are unimportant, but that many important axes of variation within a taxonomic group may be unique and not generalizable to other taxa

Summary of the pyrosequencing results performed on the individual algal cultures, the mock community and the eight treatments.

<p>Summary of the pyrosequencing results performed on the individual algal cultures, the mock community and the eight treatments.</p

Relative abundance plot of algal diversity recovered for each treatment.

<p>Relative abundance was calculated as the percentage of sequences belonging to <i>Trebouxia</i>, <i>Asterochloris</i> and additional green microalgae among all sequences recovered from each treatment. The color coding for each is reported on the right side.</p