Latitudinal environmental niches and riverine barriers shaped the phylogeography of the Central Chilean endemic Dioscorea humilis (Dioscoreaceae)

The effects of Pleistocene glaciations and geographical barriers on the phylogeographic patterns of lowland plant species in Mediterranean-climate areas of Central Chile are poorly understood. We used Dioscorea humilis (Dioscoreaceae), a dioecious geophyte extending 530 km from the Valparaíso to the Bío-Bío Regions, as a case study to disentangle the spatio-temporal evolution of populations in conjunction with latitudinal environmental changes since the Last Inter-Glacial (LIG) to the present. We used nuclear microsatellite loci, chloroplast (cpDNA) sequences and environmental niche modelling (ENM) to construct current and past scenarios from bioclimatic and geographical variables and to infer the evolutionary history of the taxa. We found strong genetic differentiation at nuclear microsatellite loci between the two subspecies of D. humilis, probably predating the LIG. Bayesian analyses of population structure revealed strong genetic differentiation of the widespread D. humilis subsp. humilis into northern and southern population groups, separated by the Maipo river. ENM revealed that the ecological niche differentiation of both groups have been maintained up to present times although their respective geographical distributions apparently fluctuated in concert with the climatic oscillations of the Last Glacial Maximum (LGM) and the Holocene. Genetic data revealed signatures of eastern and western postglacial expansion of the northern populations from the central Chilean depression, whereas the southern ones experienced a rapid southward expansion after the LGM. This study describes the complex evolutionary histories of lowland Mediterranean Chilean plants mediated by the summed effects of spatial isolation caused by riverine geographical barriers and the climatic changes of the Quaternary. Copyright: © 2014 Bischoff et al.Financial support for this study was provided by a Fundación BBVA BIOCON 05-093/06 project grant to PC and JGSM. JV was supported by a Fundación BBVA Ph.D. grant. JGSM was supported by two consecutive Spanish Aragón Government ‘‘Araid’’ and Spanish Ministry of Science and Innovation ‘‘Ramón y Cajal’’ postdoctoral contracts. PC was partially funded by a Bioflora (http://bifi.es/bioflora/) research team grant co-funded by the Spanish Aragón Government and the European Social Fund.Peer Reviewe

A K-contact simply connected 5-manifold with no semi-regular Sasakian structure

We construct the first example of a 5-dimensional simply connected compact manifold that admits a K-contact structure but does not admit a semi-regular Sasakian structure. For this, we need two ingredients: (a) to construct a suitable simply connected symplectic 4-manifold with disjoint symplectic surfaces spanning the homology, all of them but one of genus 1 and the other of genus g>1, (b) to prove a bound on the second Betti number $b_2$ of an algebraic surface with $b_1=0$ and having disjoint complex curves spanning the homology when all of them but one are of genus 1 and the other of genus g>1.Comment: 32 pages, no figures; v2. added a proof that the symplectic 4-manifold in [MRT] cannot be complex; v3. added computation of second Stiefel-Whitney class; v4. small changes. Title change

Characterization of Nuclear Microsatellite Markers for Rumex bucephalophorus (Polygonaceae) Using 454 Sequencing

Premise of the study: Nuclear microsatellite markers were developed in Rumex bucephalophorus subsp. canariensis (Polygonaceae) to investigate its genetic diversity and structure. Methods and Results: Sixteen polymorphic microsatellite markers were obtained using 454 next-generation sequencing with di-, tri-, and tetranucleotide repeats. The average number of alleles was 5.688 and 3.813 for R. bucephalophorus subsp. canariensis var. canariensis and var. fruticescens, respectively. Slightly higher levels of mean genetic diversity were found in var. canariensis (expected heterozygosity = 0.600) than in var. fruticescens (expected heterozygosity = 0.514). Cross-amplifications in related taxa within R. bucephalophorus showed good amplification and polymorphic patterns. Conclusions: These 16 novel nuclear microsatellite markers are the first in the genus Rumex and may serve as valuable tools to carry out studies on genetic diversity and structure as well as progeny studies

Caracterización y evaluación agronómica y de calidad de diferentes cultivares tradicionales de tomate para consumo en fresco

El tomate (Solanum lycopersicum L.) es actualmente la hortaliza más cultivada en el mundo dada su gran diversidad de cultivares adaptados a diferentes condiciones ambientales, prácticas culturales, destino del fruto y gustos. El uso de variedades tradicionales constituye una alternativa para obtener frutos de una calidad organoléptica superior a la de los cultivares comerciales, además de presentar una buena adaptación a las condiciones agroecológicas de las zonas donde son cultivadas. En el presente trabajo se cultivaron diez entradas tradicionales de tomate recogidas de diferentes donantes de la comunidad de Aragón y una variedad híbrida comercial utilizada como testigo y con ello evaluar la aptitud de esas entradas para su consumo en fresco. El estudio fue realizado en una finca situada en la localidad de Huesca dedicada en la actualidad al cultivo de hortaliza, el ensayo se realizó en una parcela de dicha finca, al aire libre y siguiendo criterios de agricultura ecológica. La caracterización se realizó evaluando la producción (precocidad y producción total) y utilizando descriptores morfológicos (peso, forma, cicatriz pendular, acostillado, forma de las secciones transversal y longitudinal, forma de la cicatriz del pistilo y número de lóculos) y físico-químicos o de calidad (color, firmeza con y sin piel, contenido en sólidos solubles, pH y contenido en licopeno). A partir de estos datos de caracterización se han elaborado fichas descriptivas siguiendo los estándares del BGHZ para la incorporación de estos materiales a dicho banco. El análisis estadístico de los datos permitió evaluar las fortalezas de cada una de las entradas estudiadas y establecer sus potencialidades para un posible cultivo y comercialización en este ámbito de la agricultura. Entre las entradas evaluadas “Suelo de Salas” se presentó como una entrada con muy buenas aptitudes para su comercialización en fresco. Del resto, con menor aptitudes de comercialización en canales convencionales, aparecieron entradas con buenas cualidades organolépticas (Rosa de Huesca, Rosa temprano) y otras con unas cualidades en cuanto a fisiología de fruto (Bombilla amarillo, Amarillo ácido, Blanco, Rodolfo) o conservación tras la cosecha (Mala cara) interesantes y las cuales podrían seguir estudiándose

Genetic Diversity and Population Structure of Rice Varieties Cultivated in Temperate Regions

Background After its domestication, rice cultivation expanded from tropical regions towards northern latitudes with temperate climate in a progressive process to overcome limiting photoperiod and temperature conditions. This process has originated a wide range of diversity that can be regarded as a valuable resource for crop improvement. In general, current rice breeding programs have to deal with a lack of both germplasm accessions specifically adapted to local agro-environmental conditions and adapted donors carrying desired agronomical traits. Comprehensive maps of genome variability and population structure would facilitate genome-wide association studies of complex traits, functional gene investigations and the selection of appropriate donors for breeding purposes. Results A collection of 217 rice varieties mainly cultivated in temperate regions was generated. The collection encompasses modern elite and old cultivars, as well as traditional landraces covering a wide genetic diversity available for rice breeders. Whole Genome Sequencing was performed on 14 cultivars representative of the collection and the genomic profiles of all cultivars were constructed using a panel of 2697 SNPs with wide coverage throughout the rice genome, obtained from the sequencing data. The population structure and genetic relationship analyses showed a strong substructure in the temperate rice population, predominantly based on grain type and the origin of the cultivars. Dendrogram also agrees population structure results. Conclusions Based on SNP markers, we have elucidated the genetic relationship and the degree of genetic diversity among a collection of 217 temperate rice varieties possessing an enormous variety of agromorphological and physiological characters. Taken together, the data indicated the occurrence of relatively high gene flow and elevated rates of admixture between cultivars grown in remote regions, probably favoured by local breeding activities. The results of this study significantly expand the current genetic resources available for temperate varieties of rice, providing a valuable tool for future association mapping studies

Molecular approaches reveal speciation between red- and blue-flowered plants in the Mediterranean Lysimachia arvensis and L. monelli (Primulaceae)

Flower colour has played a decisive role as an evolutionary force in many groups of plants by driving speciation. A well-known example of colour polymorphism is found across the Mediterranean populations of Lysimachia arvensis and L. monelli, in which blue- and red-flowered plants can be found. Previous studies recognized two lineages within L. arvensis differing in flower colour, but this variation has not yet been considered in a phylogenetic context. We have reconstructed the ancestral states of flower colour across Mediterranean Lysimachia spp. aiming at understanding its phylogenetic signal using the nuclear internal transcribed spacer (ITS) sequences and three plastid markers. All blue- and red-flowered specimens were nested in different clades in the ITS tree, thus supporting that L. arvensis and L. monelli are polyphyletic, whereas low phylogenetic resolution was found in plastid markers. Monophyly was reconstructed for blue-flowered L. arvensis and L. monelli samples, and similarly for red-flowered individuals of each species: (1) blue-flowered L. arvensis was reconstructed as sister to the strictly blue-flowered L. talaverae in a monophyletic clade sister to remaining Lysimachia; (2) red-flowered L. arvensis was resolved as sister to red-flowered L. monelli in a monophyletic clade; and (3) clade 2 was sister to blue-flowered L. monelli and the strictly blue-flowered L. foemina. Our results suggest that colour lineages in L. arvensis and L. monelli constitute different species, but flower colour did not promote the separation of these lineages. We propose a new name for blue-flowered L. arvensis (L. loeflingii) and a new combination for red-flowered L. monelli (L. collina), maintaining L. arvensis for red-flowered plants and L. monelli for blue-flowered plants.Fondos FEDER de la Unión Europea y el Ministerio de Ciencia e Innovación de España (MINECO)-CGL2008-02531-E, CGL2012-33270 y CGL2015-6382

Phylogenetics of the paleartic model grass "brachypodium sylvaticum" uncovers two divergent oriental and occidental micro-taxa lineages

Brachypodium sylvaticum has been selected as a model for perennial grasses, and considerable genomic resources have been generated and a reference genome and several resequenced pangenome accessions are available for this species. Despite these genomic advances, the evolution and systematics of diploid B. sylvaticum s. l. is almost unknown. The B. sylvaticum complex is formed by up to seven taxonomically close micro-taxa which differentiate from typical B. sylvaticum s. s. based on a few morphological features. Moreover, some of them show some largely disjunct geographic distributions on both sides of their native Palearctic region. In this study, we used a phylogenomic approach including representative populations from the oriental and occidental distribution range of B. sylvaticum micro-taxa to elucidate their evolutionary relationships and assess the systematic value of the morphological features that separate them. A combined plastome and nuclear phylogenetic tree supports an early split and high divergence of the oriental lineage, showing the close relationship of the Himalayan B. sylvaticum var. breviglume lineages to the Pacific B. miserum / B. kurilense clade, and the contrasting large homogeneity and low divergence of the occidental European, N African and SW and C Asian lineage, with several B. sylvaticum s. s., B. spryginii, and B. glaucovirens samples showing identical or similar sequences. Divergence time estimate analysis suggests that the oriental lineage diverged from the common ancestor in the early Pleistocene (2.0 Ma), followed by subsequent colonization and isolations in the Himalayas (2.0 – 1.7 Ma) and the Far East (0.36 Ma) in more recent times, while the occidental lineage split in the Mid-Late Pleistocene (0.97 Ma), followed by rapid radiation and postglacial spread in the western Paleartic during the last thousand years

Phenolic Compounds Content and Genetic Diversityat Population Level across the Natural Distribution Range of Bearberry (Arctostaphylos uva-ursi, Ericaceae) in the Iberian Peninsula

Bearberry (Arctostaphylos uva-ursi) is a medicinal plant traditionally employed for the treatment of urinary tract infections due to high contents of arbutin (hydroquinone β-D-glucoside), which is now mainly used as a natural skin-whitening agent in cosmetics. Bearberry has also been proposed as a natural antioxidant additive due to the high contents of phenolic compounds in leaves. We studied the variation on phenolic compounds in 42 wild populations of bearberry, aiming to elucidate if intrinsic biological, climatic, and/or geographic factors affect phenolic contents across its natural distribution in the Iberian Peninsula. Bearberry leaves were collected during autumn over a three-year period (2014-2016) in populations across a latitude and altitude gradient. Methanolic extracts showed a wide range of variation in total phenols content, and different phenolic profiles regarding arbutin (levels of this major constituent varied from 87 to 232 mg/g dr wt), but also catechin and myricetin contents, which were affected by geographic and climatic factors. Moderate levels of variation on genome size-assessed by flow cytometry-and on two plastid DNA regions were also detected among populations. Genetic and cytogenetic differentiation of populations was weakly but significantly associated to phytochemical diversity. Elite bearberry genotypes with higher antioxidant capacity were subsequently identified