Transcript Profiling of Different Arabidopsis thaliana Ecotypes in Response to Tobacco etch potyvirus Infection

The use of high-throughput transcript profiling techniques has opened the possibility of identifying, in a single experiment, multiple host mRNAs whose levels of accumulation are altered in response to virus infection. Several studies have used this approach to analyze the response of Arabidopsis thaliana to the infection by different RNA and DNA viruses. However, the possible differences in response of genetically heterogeneous ecotypes of the plant to the same virus have never been addressed before. Here we have used a strain of Tobacco etch potyvirus (TEV) experimentally adapted to A. thaliana ecotype Ler-0 and a set of seven plant ecotypes to tackle this question. Each ecotype was inoculated with the same amount of the virus and the outcome of infection characterized phenotypically (i.e., virus infectivity, accumulation, and symptoms development). Using commercial microarrays containing probes for more than 43,000 A. thaliana transcripts, we explored the effect of viral infection on the plant transcriptome. In general, we found that ecotypes differ in the way they perceive and respond to the virus. Some ecotypes developed strong symptoms and accumulated large amounts of viral genomes, while others only developed mild symptoms and accumulated less virus. At the transcriptomic level, ecotypes could be classified into two groups according to the particular genes whose expression was altered upon infection. Moreover, a functional enrichment analyses showed that the two groups differed in the nature of the altered biological processes. For the group constituted by ecotypes developing milder symptoms and allowing for lower virus accumulation, genes involved in abiotic stresses and in the construction of new tissues tend to be up-regulated. For those ecotypes in which infection was more severe and productive, defense genes tend to be up-regulated, deviating the necessary resources from building new tissues

¿Bastan los datos geoquímicos para establecer el origen del circón? Aportaciones de los esquistos cloríticos en las peridotitas de Ronda

This study deals with the scarce chlorite schists scattered through the Ronda peridotites (Betic Cordilleras, Spain) related to the intrusion of granite dykes. Chlorite schists field data and the petrography, geochemistry and geothermometry of the extracted zircon crystals, point to late magmatic melts for the zircon origin. Moreover, LA-ICPMS analyses reveal that trace and rare earth elements alone could not be indicative for the magmatic or hydrothermal origin of zircon. Therefore, the combination of that information with zircon morphology, melt inclusions, geothermometry, and structural data, when possible, is crucial in the correct zircon origin identificationEste trabajo se centra en los escasos esquistos cloríticos, asociados a la intrusión de diques graníticos, que se encuentran en las peridotitas de Ronda (Cordilleras Béticas, España). A partir de los datos de campo de los esquistos y de la petrografía, geoquímica y geotermometría de circones extraídos, se concluye que su origen está ligado a fluidos magmáticos tardíos. Además, la información obtenida mediante LA-ICP-MS confirma que los elementos trazas y las tierras raras por sí solos no son determinantes acerca del origen magmático o hidrotermal del circón. Por tanto, la combinación de dicha información con la morfología de los circones, inclusiones de fundidos, geotermometría y el estudio estructural, en el caso de ser posible, es crucial para la correcta identificación del origen del circó

Experimental evolution of an emerging plant virus in host genotypes that differ in their susceptibility to infection

This study evaluates the extent to which genetic differences among host individuals from the same species condition the evolution of a plant RNA virus. We performed a threefold replicated evolution experiment in which Tobacco etch potyvirus isolate At17b (TEV-At17b), adapted to Arabidopsis thaliana ecotype Ler-0, was serially passaged in five genetically heterogeneous ecotypes of A. thaliana. After 15 passages we found that evolved viruses improved their fitness, showed higher infectivity and stronger virulence in their local host ecotypes. The genome of evolved lineages was sequenced and putative adaptive mutations identified. Host-driven convergent mutations have been identified. Evidences supported selection for increased translational efficiency. Next, we sought for the specificity of virus adaptation by infecting all five ecotypes with all 15 evolved virus populations. We found that some ecotypes were more permissive to infection than others, and that some evolved virus isolates were more specialist/generalist than others. The bipartite network linking ecotypes with evolved viruses was significantly nested but not modular, suggesting that hard-to-infect ecotypes were infected by generalist viruses whereas easy-to-infect ecotypes were infected by all viruses, as predicted by a gene-for-gene model of infection.We acknowledge grant BFU2012–30805 from the Spanish Ministerio de Economía y Competitividad to SFE. JMC was supported by a JAE-doc contract from CSIC. JH was supported by a pre-doctoral fellowship from Ministerio de Economía y CompetitividadPeer reviewe

Intra-specific variability and biological relevance of P3N-PIPO protein length in potyviruses

BackgroundPipo was recently described as a new ORF encoded within the genome of the Potyviridae family members (PNAS 105:5897–5902, 2008). It is embedded within the P3 cistron and is translated in the +2 reading frame relative to the potyviral long ORF as the P3N-PIPO fusion protein. In this work, we first collected pipo nucleotide sequences available for different isolates of 48 Potyvirus species. Second, to determine the biological implications of variation in pipo length, we measured infectivity, viral accumulation, cell-to-cell and systemic movements for two Turnip mosaic virus (TuMV) variants with pipo alleles of different length in three different susceptible host species, and tested for differences between the two variants.ResultsIn addition to inter-specific variation, there was high variation in the length of the PIPO protein among isolates within species (ranging from 1 to 89 amino acids). Furthermore, selection analyses on the P3 cistron did not account for the existence of stop codons in the pipo ORF, but showed that positive selection was significant in the overlapping region for Potato virus Y (PVY) and TuMV. In some cases, variability in length was associated with host species, geographic provenance and/or other strain features. We found significant empirical differences among the phenotypes associated with TuMV pipo alleles, though the magnitude and sign of the effects were host-dependent.ConclusionsThe combination of computational molecular evolution analyses and experiments stemming from these analyses provide clues about the selective pressures acting upon the different-length pipo alleles and show that variation in length may be maintained by host-driven selection

Peri-Gondwanan Provenance and Geodynamic Evolution of The Guadaiza Nappe (Alpujarride Complex, Betic Cordilleras, Spain): Insights on The Paleotethyan Paleogeography

Based on the LA-ICP-MS U-Pb zircon ages of four metamorphic samples, we discuss the geochronology and provenance of the Guadaiza nappe, an allochthonous unit that underlies the Ronda peridotites (Betic Cordilleras, Spain). The Guadaiza nappe is composed of Triassic marbles overlying a metapelitic sequence with schists and migmatites. Zircons from a quartzite interlayered with the marbles yield a maximum depositional age of ca. 289 Ma that supports the Triassic age. The idiomorphic morphology of these Paleozoic zircon crystals and the lack of late-Variscan metamorphism (ca. 300 Ma) supports a proximal source area, and suggests that the marbles were discordantly deposited over the metapelitic sequence, along the northern margin of the Alboran microplate. The zircon patterns from the metapelitic sequence mainly yield Paleoproterozoic (ca. 1.6–2.5 Ga), Tonian–Stenian (ca. 1000 Ma), Ediacaran–Cryogenian (ca. 600 Ma) and Paleozoic (ca. 500 Ma) age clusters. These results suggest provenance from areas within the triangle bound by the West African Craton, the Metasaharan Craton and the Hun Superterrane during the Paleotethys opening (Silurian–Devonian). A Silurian–Carboniferous deposition age for the schist protoliths is constrained by the youngest detrital zircon population (ca. 443 Ma) and the Variscan age of their migmatization by an additional peak of around 299 Ma in the migmatites.This research was funded by Ministerio de Economía, Industria y Competitividad/Agencia Estatal de Investigación/Fondo Europeo de Desarrollo Regional, European Union, grant number CGL2017-82976-P and Grupos de Investigación, University of the Basque Country, grant number GIU20/017

Provenance Analysis of the Ojén Nappe and Its Implication for the Geodynamic History (Alpujárride Complex, Betic Cordilleras, Spain)

The Ojén nappe, an allochthonous unit that underlies the Ronda peridotites (Betic Cordilleras), is composed of Triassic marbles overlying a metapelitic sequence. In order to carry out an LA-ICP-MS U-Pb age determination and provenance analysis, detrital zircon grains from two quartzites interlayered within marbles and metapelites were extracted. The obtained results yield the youngest zircon population of 254 ± 3 Ma (Late Permian) with a mean Th/U ratio of 0.34 that supports both the Permian–Triassic age of the marble member and the felsic magma nature for zircon-bearing protoliths. The Permian zircons exhibit tight age peaks in three main populations of 292 ± 2 Ma, 278 ± 3 Ma, and 254 ± 3 Ma, in agreement with the main age populations reported from rhyolites and shallow crustal basaltic–andesite subalkaline rocks emplaced in transtensional Permian basins of the Variscan Orogen during the break-up of Pangea. Moreover, the analyzed detrital zircon grains yield age distributions with clear Tonian–Stenian (ca. 950–975 Ma), Ediacaran–Cryogenian (ca. 560–615 Ma), Ordovician (ca. 460–465 Ma), and Cisuralian peaks (ca. 280–290 Ma) and smoothed Mesoproterozoic peaks that point to a weak and residual Cadomian peri-Gondwanan terrane inheritance. The identified Middle Ordovician detrital zircon populations (460–465 Ma) strengthen the hypothesis that the Alborán domain would be located along the southern passive margin of the European Hunic superterrane.This research was funded by Ministerio de Economía, Industria y Competitividad/Agencia Estatal de Investigación/Fondo Europeo de Desarrollo Regional, European Union (grant number CGL2017-82976-P) and Grupos de Investigación, University of the Basque Country (grant number GIU20/017)

Geochemistry and geodynamic frame of the Ojen Nappe´s eclogites and amphibolites, Alpujarride Complex, Betic Cordilleras

Amphibolite bodies with eclogite relics are found interlayered between the Ojen nappe´s crustal rocks, below the Ronda peridotites of the Betic Cordilleras (southern Spain). We present a geochemical study of such amphibolites and retrogressed eclogites, from which it is possible to deduce a gabbroic origin for their protoliths. We propose that their intrusion in the continental crust took place in a rift setting of Jurassic to Lower Cretaceous age. The recognition of this rifting event in the Alpujarride Complex places an additional constraint for Mesozoic reconstructions of the Western Mediterranea

Structural zoning in a serpentinite-bearing shear zone (Peña Parda Fault, Ronda peridotites)

We study deformation structures in a serpentinite-bearing normal shear zone in the Ronda peridotites, southern Spain. The fault zone displays a structural zoning composed by four domains showing similar strain gradients. Deformation is partitioned into distributed deformation expressed by foliated serpentinites and S-C structures and localized deformation expressed by R and P shear planes at lower and upper portions, respectively, of each domain. Such a structural zoning suggests that stable shear creep alternates with intermittent seismogenic events during the fault activit

Mantle diapirism induced by delamination in the Ronda peridotites (Betic Cordillera)

The contribution of asthenosphere diapirs to the exhumation of Orogenic Lherzolites from the mantle to the Earth’s surface stands as a major issue in the evolution of orogenic belts. Structural and textural data from the Carratraca massifs of the Ronda peridotites, in the Betic Cordillera of southern Spain, provide evidence for a narrow mantle diapir that was formed in Early Miocene times. Its development spent 1.1 Ma at an ascent rate of less than 4.5 mm/y. When set in its geological and petrological context, this diapir documents the injection of hot asthenosphere into older and cooler lithospheric mantle, in response to the delamination of the thickened lithosphere keel formed during the Mesozoic and Cenozoic convergence of the African and Iberian plates from Cretaceous times onward

Diseño y análisis de un texto para la enseñanza de la circunferencia a través de configuraciones epistémicas

En el presente artículo se desarrolla una propuesta para la enseñanza de la circunferencia en el nivel superior y los elementos relacionados con ella, tomando como base los constructos teóricos del enfoque ontosemiótico y la instrucción matemática (EOS), la cual emana de las estrategias institucionales para contrarrestar los bajos logros académicos de los estudiantes en sus habilidades matemáticas. A través de un análisis del texto con la noción de configuración epistémica, se revisa la articulación de los objetos primarios que intervienen y emergen del él, así como la identificación de posibles conflictos semióticos