Completely sequenced plastomes provide a valuable source of information about the duplication, loss, and transfer events of chloroplast genes and phylogenetic data for resolving relationships among major groups of plants. Moreover, they can also be useful for exploiting chloroplast genetic engineering technology. Ericales account for approximately six per cent of eudicot diversity with 11,545 species from which only three complete plastome sequences are currently available. With the aim of increasing the number of ericalean complete plastome sequences, and to open new perspectives in understanding Mediterranean plant adaptations, a genomic study on the basis of the complete chloroplast genome sequencing of Arbutus unedo and an updated phylogenomic analysis of Asteridae was implemented. The chloroplast genome of A. unedo shows extensive rearrangements but a medium size (150,897 nt) in comparison to most of angiosperms. A number of remarkable distinct features characterize the plastome of A. unedo: five-fold dismissing of the SSC region in relation to most angiosperms; complete loss or pseudogenization of a number of essential genes; duplication of the ndhH-D operon and its location within the two IRs; presence of large tandem repeats located near highly re-arranged regions and pseudogenes. All these features outline the primary evolutionary split between Ericaceae and other ericalean families. The newly sequenced plastome of A. unedo with the available asterid sequences allowed the resolution of some uncertainties in previous phylogenies of Asteridae.

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RESUMEN. Impacto del ozono troposférico sobre la anatomía foliar de Abies pinsapo Boiss. I: Estudio de la distribución de daños. Con el fin de elaborar unos criterios unificados para la evaluación del impacto del ozono troposférico y compararlos con la respuesta de las poblaciones naturales de Sierra Bermeja y Sierra de las Nieves, se han reproducido en cámaras Open Top, ambientes filtrados y enriquecidos con ozono para realizar una caracterización microscópica del daño que produce el ozono troposférico sobre Abies pinsapo Boiss. Los resultados demuestran que pese a que la morfología foliar permanece inalterada tras someter durante un mes en condiciones de 30 ppb durante 8 horas al día, a nivel tisular se han producido daños de consideración que afectan de este endemismo.Palabras clave. Anatomía, Abies pinsapo, ozono, cámaras Open Top.ABSTRACT. Tropospheric ozone injury on the foliar anatomy of Abies pinsapo Boiss. I: Study of damage distribution. With the aim of develop unified criteria to evaluate the tropospheric ozone injury and compare with responses in Abies pinsapo Boiss. in natural populations in Sierra Bermeja and Sierra de las Nieves, it has been reproduced in Open Top Chambers conditions of filtered air and addition of controlled amounts of ozone. Results show that despite leaf morphology remains unaltered after a treatment with 30 ppb 8 hours per day, at tissue level there have been injuries that affect this endemism.Key words. Anatomy, Abies pinsapo, ozone, Open Top chambers.

Among the most intriguing mysteries in the evolutionary biology of photosynthetic organisms are the genesis and consequences of the dramatic increase in the mitochondrial and nuclear genome sizes, together with the concomitant evolution of the three genetic compartments, particularly during the transition from water to land. To clarify the evolutionary trends in the mitochondrial genome of Archaeplastida, we analyzed the sequences from 37 complete genomes. Therefore, we utilized mitochondrial, plastidial and nuclear ribosomal DNA molecular markers on 100 species of Streptophyta for each subunit. Hierarchical models of sequence evolution were fitted to test the heterogeneity in the base composition. The best resulting phylogenies were used for reconstructing the ancestral Guanine-Cytosine (GC) content and equilibrium GC frequency (GC*) using non-homogeneous and non-stationary models fitted with a maximum likelihood approach. The mitochondrial genome length was strongly related to repetitive sequences across Archaeplastida evolution; however, the length seemed not to be linked to the other studied variables, as different lineages showed diverse evolutionary patterns. In contrast, Streptophyta exhibited a powerful positive relationship between the GC content, non-coding DNA, and repetitive sequences, while the evolution of Chlorophyta reflected a strong positive linear relationship between the genome length and the number of genes.

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