Species Boundaries and Population Divergence in the Pyrenean Endemic Relict Genus Borderea (Dioscoreaceae) as Revealed by Microsatellite (SSR) and Other Hypervariable Markers

Microsatellite alleles were used to delimit the genetic boundaries and divergence of the two relictual endemic Pyrenean taxa Borderea chouardii and B. pyrenaica (Dioscoreaceae), and to infer the different life histories followed by each species. Our study was conducted on the same populations previously analyzed with allozymes and RAPD markers. The three studied data sets were congruent in the inference of a single evolutionary scenario for the split of the two Borderea taxa from a common Tertiary ancestor in the Prepyrenees, thus supporting their taxonomic treatment as separate species. However, the more variable SSR and RAPD data provided better resolution for a stepping-stone model of local colonization of B. pyrenaica populations from southern Prepyrenean refugia to the northern Pyrenees. SSR markers proved to be more robust than RAPD markers in assessing the genetic structure of recently diverged populations of B. pyrenaica and thus qualified as the best molecular markers for fine-scale evolutionary investigations of Dioscoreaceae. Furthermore, microsatellites rendered unique clues to decipher the mechanisms involved in the origin of these relictual species and their genetic background. Borderea was shown to be a tetraploid genus of hybrid origin with a chromosome base number of x = 6. Phylogenetic data, karyological evidence, and our present knowledge based on microsatellite analyses allowed us to speculate that the Pyrenean endemic genus Borderea and its sister taxon, the Mediterranean genus Tamus, represent some of the oldest paleopolyploid lineages of the mostly pantropical yam family

Phylogeny and systematics of the western Mediterranean Vella pseudocytisus - V. aspera complex (Brassicaceae)

The evolution and taxonomy of the core members of subtribe Vellinae (Brassicaceae), comprising Vella aspera, V. Bourgeana, and V. Pseudocytisus, is still poorly known. We reconstructed the evolutionary relationships among these taxa and other Vellinae and close Brassicaceae using nuclear ITS and plastid trnTF phylogenies, and analyzed the phenotypic traits that differentiate the infraspecific ranks of V. Pseudocytisus. Our phylogenetic analyses show: i) an early divergence of Succowia within the Brassiceae-Sisymbrieae sensu lato clade; ii) the nested positions of Vella bourgeana (syn. Euzomodendron bourgaeanum) and V. Aspera (syn. Boleum asperum) within the Vella clade; and iii) the split of 5 lineages within the V. Pseudocytisus clade (NW African subspecies glabrata 2x; SE Spain subspecies pseudocytisus 2x; C Spain subspecies pseudocytisus 4x; NE Spain subspecies paui 4x Alfambra Valley; and NE Spain subspecies paui 4x Turia Valley). Phenotypic traits support the differentiation of the diploid and tetraploid cytotypes of V. Pseudocytisus subsp. Pseudocytisus. Our data support the separation of Succowia from the Vellinae and the erection of a new subspecies within V. Pseudocytisus (Vella pseudocytisus subsp. Orcensis subsp. Nov.). They also corroborate the inclusion of Boleum and Euzomodendron within Vella

Brachypodium: A Monocot Grass Model Genus for Plant Biology

The genus Brachypodium represents a model system that is advancing our knowledge of the biology of grasses, including small grains, in the postgenomics era. The most widely used species, Brachypodium distachyon, is a C-3 plant that is distributed worldwide. B. distachyon has a small genome, short life cycle, and small stature and is amenable to genetic transformation. Due to the intensive and thoughtful development of this grass as a model organism, it is well-suited for laboratory and field experimentation. The intent of this review is to introduce this model system genus and describe some key outcomes of nearly a decade of research since the first draft genome sequence of the flagship species, B. distachyon, was completed. We discuss characteristics and features of B. distachyon and its congeners that make the genus a valuable model system for studies in ecology, evolution, genetics, and genomics in the grasses, review current hot topics in Brachypodium research, and highlight the potential for future analysis using this system in the coming years

Taxonomic differentiation of iberian knapweeds (Centaurea sects. Jacea and Lepteranthus, Asteraceae) and genetic isolation of infraspecific floral morphotypes

The taxonomic boundaries of Centaurea L. species and infraspecific taxa are often blurred by hybridizations. However, counterbalancing genetic isolation contributes to maintaining taxonomic limits and fostering rapid speciation processes. Radiant (R) and non-radiant (NR) capitula are two major floral morphs present in Centaurea. However, it is unclear how gene flow affects the distribution of floral morphotypes across populations and taxa. We have investigated the taxonomic differentiation and potential effect of genetic isolation in R and NR populations of Iberian Centaurea sects. Jacea (Mill.) Pers. ex Dumort. and Lepteranthus (Neck. ex DC.) Dumort. A total of 510 individuals from 58 populations (12 taxa) were analyzed using 165 amplified fragment length polymorphism (AFLP) markers. Genetic diversity and structure parameters were estimated at the taxon, population, and floral morphotypic levels. We tested whether there was correlation between population pairwise fixation index (Fst) genetic distances and the inbreeding coefficient (Fis), taken as a surrogate of reproductive isolation between the R and NR morphotypes of each group, and also taking into account geographic distances, using distance-based redundancy analysis (dbRDA). We also performed isolation by distance (IBD) tests between different floral morphotypes, aiming to infer the impact of genetic isolation on evolutionary and taxonomic divergence of the individuals. The taxa of Centaurea sects. Jacea and Lepteranthus constitute independent evolutionary lineages. Most of the detected genetic clusters match the taxonomic circumscription proposed in our most recent treatments. Genetic diversity was highest in C. debeauxii Godr. & Gren. subsp. debeauxii and subsp. grandiflora (Gaudin ex Schübl. & G. Martens) Devesa & Arnelas and in C. jacea L. subsp. angustifolia (DC.) Gremli (R) and lowest in C. nevadensis Boiss. & Reut. (NR) within the Centaurea sect. Jacea clade, whereas it was highest in C. linifolia L. within the Centaurea sect. Lepteranthus clade. Population-level dbRDA tests did not detect a significant correlation of R versus NR genetic distances and Fis values in any of the studied cases; by contrast, they detected significant correlation with longitude (C. jacea subsp. angustifolia, C. debeauxii, C. linifolia–C. stuessyi Arnelas, Devesa & E. López) or latitude (C. nigra L.). IBD analysis at the individual level showed that, in addition to geography, other morphotype-related factors may affect the genetic differentiation of R versus NR morphs in C. nigra, C. debeauxii, and C. linifolia–C. stuessyi. These results suggest that the fixation of the different morphs within the same taxon or group may be explained by geographic isolation, though we could not discount other potential unknown factors that could have contributed to microspeciation in these recently divergent populations, which originated only several thousands of years ago

Diagnóstico de la erosión de suelos en la Microcuenca Alta de Yanaca -Aymaraes - Apurímac 2019

El calentamiento global que está experimentando nuestro planeta, están originando trastornos en el clima de todo el mundo con sequías y fuertes precipitaciones pluviales lo que permite hacer la siguiente interrogante; ¿Cuál es el diagnóstico de la erosión hídrica de los suelos en la microcuenca Alta de Yanaca - Aymaraes - Apurímac, 2020? Considerando el siguiente objetivo; Determinar la perdida de los suelos a consecuencia de las precipitaciones pluviales por el método de la ecuación universal de pérdida de suelos (USLE) en la Microcuenca Alta de Yanaca - Aymaraes Determinar el índice de erosividad de la lluvia y determinar el índice de erosividad al suelo. Haciendo uso de la ecuación universal de pérdida de suelo USLE y la determinación de los factores de USLE mediante observación técnica se ha llegado a los siguientes resultados: La pérdida aproximada de suelo determinado en la Microcuenca Alta de Yanaca son:3.67 ton/ha/año en promedio y se encuentra en una clasificación de tipo de erosión baja, mientras que la zona media tiene una pérdida aproximada de 12.55 ton/ha/año con una clasificación de alta, lo que conduce a pensar en realizar actividades que permitan reducir dicha erosión y la zona alta con 56.04 ton/ha/año tiene clasificación de severa y ello ocurre por varios factores debido a su altitud, respecto al índice de erosividad de la lluvia en la microcuenca alta de Yanaca es de 407.52 Mj.mm/ha debido a las condiciones medioambientales de dicha zona, según la tabla de clasificación del factor de erosividad de la lluvia es normal ya que se encuentra por debajo de 1000 Mj.mm/ha, y la zona alta tiene en promedio K=0.43, lo que confirma de que esta zonas es muy susceptible a la erosión del suelo luego la zona baja tiene un factor K=0.3

TDAH y función ejecutiva

El trastorno por déficit de atención e hiperactividad es un trastorno mental que comprendediferentes dificultades persistentes, como hiperactividad, conducta impulsiva y prestar atención.Dada la alta incidencia del trastorno y la preocupación social que genera, en este trabajo nos hemos centrado en hacer una revisión teórica en la que abordaremos el diagnostico, las posibles causas y sus consecuencias en la vida laboral. Además, profundizaremos un poco en la función ejecutiva, donde hablaremos de sus características y, por último, concluiremos con una pincelada sobre diferentes propuestas de intervenciones basadas en las funciones ejecutivas en el TDAH.<br /

Comparatively Barcoded Chromosomes of Brachypodium Perennials Tell the Story of Their Karyotype Structure and Evolution

The Brachypodium genus is an informative model system for studying grass karyotype organization. Previous studies of a limited number of species and reference chromosomes have not provided a comprehensive picture of the enigmatic phylogenetic relationships in the genus. Comparative chromosome barcoding, which enables the reconstruction of the evolutionary history of individual chromosomes and their segments, allowed us to infer the relationships between putative ancestral karyotypes of extinct species and extant karyotypes of current species. We used over 80 chromosome-specific BAC (bacterial artificial chromosome) clones derived from five reference chromosomes of B. distachyon as probes against the karyotypes of twelve accessions representing five diploid and polyploid Brachypodium perennials. The results showed that descending dysploidy is common in Brachypodium and occurs primarily via nested chromosome fusions. Brachypodium distachyon was rejected as a putative ancestor for allotetraploid perennials and B. stacei for B. mexicanum. We propose two alternative models of perennial polyploid evolution involving either the incorporation of a putative x = 5 ancestral karyotype with di erent descending dysploidy patterns compared to B. distachyon chromosomes or hybridization of two x = 9 ancestors followed by genome doubling and descending dysploidy. Details of the karyotype structure and evolution in several Brachypodium perennials are revealed for the first time

Enriched root bacterial microbiome in invaded vs native ranges of the model grass allotetraploid Brachypodium hybridum

Invasive species can shift the composition of key soil microbial groups, thus creating novel soil microbial communities. To better understand the biological drivers of invasion, we studied plant-microbial interactions in species of the Brachypodium distachyon complex, a model system for functional genomic studies of temperate grasses and bioenergy crops. While Brachypodium hybridum invasion in California is in an incipient stage, threatening natural and agricultural systems, its diploid progenitor species B. distachyon is not invasive in California. We investigated the root, soil, and rhizosphere bacterial composition of Brachypodium hybridum in both its native and invaded range, and of B. distachyon in the native range. We used high-throughput, amplicon sequencing to evaluate if the bacteria associated with these plants differ, and whether biotic controls may be driving B. hybridum invasion. Bacterial community composition of B. hybridum differed based on provenance (native or invaded range) for root, rhizosphere, and bulk soils, as did the abundance of dominant bacterial taxa. Bacteroidetes, Cyanobacteria and Bacillus spp. (species) were significantly more abundant in B. hybridum roots from the invaded range, whereas Proteobacteria, Firmicutes, Erwinia and Pseudomonas were more abundant in the native range roots. Brachypodium hybridum forms novel biotic interactions with a diverse suite of rhizosphere microbes from the invaded range, which may not exert a similar influence within its native range, ostensibly contributing to B. hybridum''s invasiveness. These associated plant microbiomes could inform future management approaches for B. hybridum in its invaded range and could be key to understanding, predicting, and preventing future plant invasions

Correction to: Brachypodium: 20 years as a grass biology model system; the way forward?:(Trends in Plant Science 27, 1002–1016, 2022)

It has been 20 years since Brachypodium distachyon was suggested as a model grass species, but ongoing research now encompasses the entire genus. Extensive Brachypodium genome sequencing programmes have provided resources to explore the determinants and drivers of population diversity. This has been accompanied by cytomolecular studies to make Brachypodium a platform to investigate speciation, polyploidisation, perenniality, and various aspects of chromosome and interphase nucleus organisation. The value of Brachypodium as a functional genomic platform has been underscored by the identification of key genes for development, biotic and abiotic stress, and cell wall structure and function. While Brachypodium is relevant to the biofuel industry, its impact goes far beyond that as an intriguing model to study climate change and combinatorial stress