Dues espècies endèmiques de Carthamus a Algèria i el seu potencial com a font de gens per a la millora en l’eficiència d’ús de l’aigua en el safrà bord

Noticia publicada en la web institucional del Instituto Botánico de Barcelona el 3 de febrero de 2017 -- Disponibles PDFs en español y catalán y capturas de pantalla de la noticia en la web.Peer reviewe

Delimitació genèrica del complex Carthamus-Carduncellus: un assaig de biosistemàtica i sistemàtica molecular

248 p., gráf., fot. -- Memoria presentada por Roser Vilatersana para optar al título de Doctora en Biología por la Universidad de Barcelona en 2002.Peer reviewe

Plant-herbivore interactions or colonization history: what drives changes in plant chemical defenses after invasion?

Biological invasions offer a good opportunity to study the changes in plant-herbivore interactions at ecological and evolutionary levels, because introduced plants encounter a complete novel biotic environment. Once in the novel range, plants generally experience a decreased herbivore predation due to a loss of specialist herbivores from the plant native area. This lower herbivory has been associated to changes in plant chemical defenses at population level. With no enemies associated, plants assigning more resources to growth and reproduction and fewer to chemical defenses would be favorable selected increasing the species invasion capacity, as suggested by the Evolution of Increased Competitive Ability (EICA) hypothesis. However, levels of secondary metabolites are highly determined by plant genetics, and thus changes in chemical defenses after invasion could be a result of the plant colonization history. To determine whether changes in plant chemical defenses after invasion are a result of an evolutionary process driven by herbivores or simply determined by the plant invasion pathways, we have conducted an study using Senecio pterophorus (Asteraceae) as a model system. A broad biogeographical survey was conducted covering all areas where S. pterophorus had been previously reported, including the native range (South Africa), the expanded range (Western Cape) and two introduced regions (Australia and Europe). Levels of in situ herbivory were determined for 640 individual plants. Additionally, leaves and seeds were collected to analyze genetic neutral markers (AFLPs) and chemical defenses (pyrrolizidine alkaloids). S. pterophorus from the invaded areas (Australia and Europe) suffered lower herbivory compared to plants from the native area (South Africa), and levels of pyrrolizidine alkaloids were higher in Australia and lower in Europe compared to plants from South Africa. We discuss whether the phylogeographical origin or, in contrast, the decrease in herbivore predation in the introduced populations can explain the observed differences in the type and concentrations of pyrrolizidine alkaloids after invasion

Reinterpretation of Cynara baetica based on a principle of integrative species delimitation

Póster presentado al XIX International Botanical Congress (IBC 2017), celebrado del 23 al 29 de julio de 2017, en Shenzhen, ChinaCynara is a Mediterranean genus from the family Compositae that currently includes nine species. One of them is Cynara baetica, a diploid (2n = 34) perennial herb distributed in both sides of Strait of Gibraltar (the gateway between Atlantic Ocean and Mediterranean Sea). Historically, it was described as two different species: (1) Cynara alba, that grows in open areas in deep and nitrogenous soils on calcareous bedrocks at altitudes between 500 and 1700 m in southern Spain, and (2) Cynara hystrix, that occurs in roadside ditches and open areas under the same soil conditions at somewhat higher altitudes (from 900 to 2100 m) in northern Morocco. In 1992, a morphologic study carried out by A. Wiklund merged these two species in one (Cynara baetica) although separated into two subspecies: C. baetica subsp. baetica, for the Spanish populations; and C. baetica subsp. marocanna, for the Moroccan ones. The aims of the present study are to: (i) analyse the genetic diversity within and between Cynara baetica populations, including samples from the two subspecies (subsp. baetica and subsp. maroccana); (ii) infer the phylogeographic pattern of C. baetica and the role of Strait of Gibraltar as a barrier; (iii) test whether there are morphologic, genetic and/or ecological differences between both subspecies; and (iv) provide conservation guidelines. To achieve these goals, and following the most recent approximations on species delimitation, phylogenetic and population genetic analyses (based on both nuclear¿three AFLP primer combinations¿and plastid¿two cpDNA regions¿DNA markers) were combined with ecological niche modelling (ENM) and morphologic studies. Results obtained showed a clear genetic, morphological and ecological differentiation between the two subspecies. According to these results the current taxonomic treatment is modified and the conservation guidelines are proposed according this taxonomical change.Peer reviewe

Temporal origins and diversification of Artemisia and allies (Anthemideae, Asteraceae)

Temporal origins and diversification of Artemisia and allies (Anthemideae, Asteraceae).- To assess temporal origins and diversification of lineages within subtribe Artemisiinae and Artemisia group a penalized likelihood analysis was applied on nrDNA ITS and ETS of 63 representatives. The tree was calibrated at the stem node of the Kaschgaria/ Artemisia lineage with the most reliable early Artemisia fossil pollen record from Late Oligocene (23 Ma). The results from this study suggest that the origin of the subtribe goes back to the Late Oligocene (24.6 ± 2.6 Ma) whilst the onset of differentiation of the genus Artemisia and most closely related genera is dated to the Early Miocene (19.8 ± 2.3 Ma). Divergence ages for lineages within the Artemisia group are often between the Early and Middle Miocene, whereas their radiations mostly occurred in the Late Miocene and Pliocene. The temporal context was also used to examine biogeographic and morphological (capitula and pollen type) evolution. Within the Artemisia group all lineages except the North American endemic have colonized the Mediterranean Basin at different epochs from Asian ancestors. Our analyses suggest the divergence of the North American endemic group from Asian ancestors (10.8 ± 1.5 Ma) in the Late Miocene. Homogamous-discoid capitula, characteristic of subgenera Seriphidium and Tridentatae, evolved not only in different geographic regions, but also at different times (2.0 ± 0.8 Ma and 7.9 ± 0.9 Ma respectively) within the Artemisia group. The loss of fertility of central flowers of disciform capitula should be considered as an ancient event in the genus since subgenus Dracunculus is one of the first groups that diverged (17.6 ± 2.1 Ma)

The invasion of Senecio pterophorus across continents : multiple, independent introductions, admixture and hybridization

Senecio pterophorus (Compositae) is a perennial shrub native to eastern South Africa that was introduced into the Western Cape in South Africa and Australia approximately 100 years ago and into Europe (Italy and Spain) more than 25-30 years ago. In this study, the aims were to unravel the putative sources of the introduced populations and identify the changes in genetic diversity after invasion using molecular markers and phylogeographic and population genetic analyses. We sampled the entire area of distribution for S. pterophorus extensively. Based on the results, three lineages were established along a latitudinal and climatic gradient in the native range (south, central, central/north) with high levels of admixture. Multiple, independent introductions occurred in the four invaded ranges. The central/northern lineage (humid climate) was the primary source for all of the invaded regions (with drier climates), although a secondary role was revealed for the southern lineage in the Western Cape and the central/northern lineage in Australia and Spain. The genetic diversity was slightly lower in the Spanish and Australian populations than that in the native populations. A variety of demographic and genetic processes affected the amount and structure of genetic diversity in the invaded areas, including multiple introductions and admixture (Western Cape, Australia and Spain) as well as pre-invasive hybridization (Italy). The patterns of dispersion support a hypothesis of rapid evolution of S. pterophorus after invasion in response to novel climatic conditions

Systematics and phylogeography of the Mediterranean Helichysum pendulum complex (Compositae) inferred from nuclear and chloroplast DNA and morphometrics analyses

Multiple factors related to complex geomorphological and climatic history, in addition to biological factors such as hybridization, hinder the definition of some Mediterranean plant groups. The existence of controversial taxonomic treatments, the possible hybridization events involved, and its unknown evolutionary history, make the Helichrysum pendulum complex of H. sect. Stoechadina an ideal model to understand general processes of Mediterranean plant systematics and evolution. The mosaic range of the complex, which is distributed over several islands and continental areas in the western-central Mediterranean Basin, provides an opportunity to investigate how past connections and disconnections between landmasses may have determined the current geographic distribution of genetic variation in this area. The cpDNA region rpl32-trnL intergenic spacer and the nrDNA region ETS were sequenced for 1-8 individuals from each of the 44 populations sampled, covering all taxa and the whole geographic range of the complex. These individuals were analysed together with a broad sampling of the remaining members of sect. Stoechadina. In addition, detailed multivariate analyses of morphological characters were performed for the whole section and for the H. pendulum complex. Considering together distinctive genetic and morphological traits, our species concept is presented and discussed in a context of integrative taxonomy, and five species are recognized within the complex: H. errerae, H. melitense, H. pendulum, H. saxatile and H. valentinum. The first three species are recognizable by qualitative and quantitative morphological traits, and are genetically distinguishable from the rest as shown by the molecular markers analysed. The two last species are reported here to have a putative ancient hybrid origin and are also genetically distinguishable from the rest but morphologically recognisable only by quantitative characters. Phylogenetic relationships shown by nuclear and chloroplast markers, and an intermediate morphology between the two putative parental taxa, point to H. pendulum and H. italicum as the putative parental taxa for H. saxatile, and H. pendulum and H. stoechas as putative parental taxa for H. valentinum. In a discriminant analysis of the five species, 97.8% of all individuals were classified correctly. The high level of haplotype and ribotype diversity observed in North Africa indicates that this region is either the area of origin of the complex or a secondary contact zone. Our results suggest that the complex colonized several islands and migrated through the Gibraltar and Sicilian Straits during phases of low sea level, favoured by local dispersal events that promoted its gradual range expansion. The occurrence of the complex in the Balearic Islands, which have remained isolated even during low sea level phases, could be explained by stochastic long-distance dispersal events

Comparative phylogeography of chloroplast and nuclear DNA markers reveals ancient and present hybridization in the Mediterranean Helichrysum pendulum complex (Compositae)

The geological and climatic history of the Mediterranean basin over the last 6 million years has been determinant in shaping current geographic distribution of genetic variation in organisms. Phylogeographical approaches are considered one of most useful analysis for unraveling the evolutionary history of species. The Helichrysum pendulum complex is a group of three closely related plant species distributed in several islands and isolated continental localities of the Western-Central Mediterranean basin, providing an ideal case of study to analyze the processes involved in modelling its current genetic structure. Two cpDNA region rpl32-trnL intergenic spacer and the nrDNA region ETS were sequenced for 1-8 individuals from each of the 44 total populations sampled, covering the whole geographic range of the complex. Our results suggest that the complex originated in northern Africa and colonized several islands and continental areas of the northern Basin through the Gibraltar and Sicilian straits during phases of low sea level, favored by long distance dispersal events. While ETS data suggest a model of isolation by distance and show a main genetic barrier between populations of Western and Central Mediterranean areas, the rpl32-trnL reveals the existence of two divergent and not geographically structured haplotype groups within the complex. Ancient hybridization events among lineages of sect. Stoechadina are suggested as the most plausible cause for the haplotypes pattern observed, while several evidences of current hybridization between H. pendulum and several species of sect. Stoechadina are also detected in ETS data

First genome size assessments in Carduncellus and its related genera Femeniasia and Phonus (Asteraceae, Cardueae), with data on 21 taxa

Genome size of 18 species of the genus Carduncellus, two species of the related genus Phonusand the monotypic genus Femeniasia (F. balearica) has been assessed by flow cytometry for the first time. Ploidy levels were assigned using genome size data together with previously reported chromosome counts. A phylogenetic framework was built to visualize how cytogenetic traits distributed across taxa. The results confirmed three ploidy levels (2x, 4x and 6x), with a predominance of diploids. The 2C values ranged from 3.24 pg in Carduncellus calvusto 11.16 pg in C. erio-cephalus, whereas monoploid genome size (1Cx) ranged from 1.29 pg in C. duvauxii (4x)to 2.30 pg in Phonus rhiphaeus (2x). The mean 1Cx for tetraploids was lower than for diploids. For each ploidy level, genome size values of Carduncellus, Femeniasia and Phonus were found to be higher than those of Carthamus. This result is consistent with a trend frequently observed in plants, of higher genome sizes in long life cycle taxa compared to short-lived relative