Climatic niche and neutral genetic diversity of the six Iberian pine species: a retrospective and prospective view

Quaternary climatic fluctuations have left contrasting historical footprints on the neutral genetic diversity patterns of existing populations of different tree species. We should expect the demography, and consequently the neutral genetic structure, of taxa less tolerant to particular climatic extremes to be more sensitive to long-term climate fluctuations. We explore this hypothesis here by sampling all six pine species found in the Iberian Peninsula (2464 individuals, 105 populations), using a common set of chloroplast microsatellite markers, and by looking at the association between neutral genetic diversity and species-specific climatic requirements. We found large variation in neutral genetic diversity and structure among Iberian pines, with cold-enduring mountain species (Pinus uncinata, P. sylvestris and P. nigra) showing substantially greater diversity than thermophilous taxa (P. pinea and P. halepensis). Within species, we observed a significant positive correlation between population genetic diversity and summer precipitation for some of the mountain pines. The observed pattern is consistent with the hypotheses that: (i) more thermophilous species have been subjected to stronger demographic fluctuations in the past, as a consequence of their maladaptation to recurrent glacial cold stages; and (ii) altitudinal migrations have allowed the maintenance of large effective population sizes and genetic variation in cold-tolerant species, especially in more humid regions. In the light of these results and hypotheses, we discuss some potential genetic consequences of impending climate change

Análisis transcriptómico de la formación de xilema traumático en Pinus canariensis Chr. Sm. ex D.C.

Analizamos la formación del xilema traumático hibridando un microarray con muestras recogidas a tres tiempos tras la realización de la herida (H1, H2 y H3), comparándolo con la formación de madera no traumática

De novo assembly and annotation of a transcriptome during xylogenesis in Pinus canariensis Chr. Sm. ex DC

Nowadays, there is a great amount of genomic and transcriptomic data available about forest species, including ambitious projects looking for complete sequencing and annotation of different gymnosperm genomes [1, 2]. Pinus canariensis is an endemic conifer of the Canary Islands with re-sprouting capability and resilience against fire and mechanical damage, as result of an adaptation to volcanic environments. Additionally, this species has a high proportion of axial parenchyma compared with other conifers, and this tissue connects with radial parenchyma allowing transport of reserves. The most internal tracheids stop accumulating water [3], and get filled of resins and polyphenols synthesized by the axial parenchyma; this is the so-called ?torch-heartwood? [4], which avoids decay. This wood achieves very high prices due to its particular resistance to rot. These features make P. canariensis an interesting model species for the analysis of these developmental processes in conifers. In this study we aim to perform a complete transcriptome annotation during xylogenesis in Pinus canariensis, using next-generation sequencing (NGS) -Roche 454 pyrosequencing-, in order to provide a genomic resource for further analysis, including expression profiling and the identification of candidate genes for important adaptive features

Geography determines genetic relationships between species of mountain pine (Pinus mugo complex) in western Europe

Aim  Our aims were to test whether morphological species of mountain pines were genetically supported in the western part of the distribution range of the Pinus mugo species complex (Pinus mugo Turra sensu lato), to resolve genetically homogeneous clusters of populations, to determine historical demographic processes, and to assess the potential hybridization of mountain pines with Scots pine, Pinus sylvestris L. Location  Populations were sampled in the Iberian System, the Pyrenees, the French Mont Ventoux, Vosges and Jura mountains, the German Black Forest and throughout the Alps. This corresponded to a range-wide sampling for mountain pine sensu stricto (Pinus uncinata Ram.) and to a sampling of the western parts of the ranges of dwarf mountain pine (Pinus mugo Turra sensu stricto) and bog pine/peatbog pine [Pinus rotundata Link/Pinus × pseudopumilio (Willk.) Beck]. Methods  In total, 786 individuals of P. mugo sensu lato from 29 natural populations, and 85 individuals of P. sylvestris from four natural populations were genotyped at three chloroplast microsatellites (cpSSRs). Populations were characterized for standard genetic diversity statistics and signs of demographic expansion. Genetic structure was explored using analysis of molecular variance, differentiation statistics and Bayesian analysis of population structure (BAPS). Results  One hundred haplotypes were identified in P. mugo sensu lato. There was a stronger differentiation between geographical regions than between morphologically identified taxa (P. mugo sensu stricto, P. uncinata and P. rotundata/P. ×pseudopumilio). Overall genetic differentiation was weak (GST = 0.070) and displayed a clear phylogeographic structure [NST = 0.263, NST > NST (permuted), P < 0.001]. BAPS identified a Pyrenean and an Alpine gene pool, along with several smaller genetic clusters corresponding to peripheral populations. Main conclusions  The core regions of the Pyrenees and Alps were probably recolonized, respectively by P. uncinata and P. uncinata/P. mugo sensu stricto, from multiple glacial refugia that were well connected by pollen flow within the mountain chains. Pinus rotundata/P. × pseudopumilio populations from the Black Forest, Vosges and Jura mountains were probably recolonized from various glacial populations that kept their genetic distinctiveness despite late glacial and early Holocene expansion. Marginal P. uncinata populations from the Iberian System are compatible with elevational shifts and long-term isolation. The causes of haplotype sharing between P. mugo sensu lato and P. sylvestris require further researc

Heterologous Expression of a Plant Small Heat-Shock Protein Enhances Escherichia Coli Viability under Heat And Cold Stress Ref.: 1

A small heat-shock protein (sHSP) that shows molecular chaperone activity in vitro was recently purified from mature chestnut (Castanea sativa) cotyledons. This protein, renamed here as CsHSP17.5, belongs to cytosolic class I, as revealed by cDNA sequencing and immunoelectron microscopy. Recombinant CsHSP17.5 was overexpressed in Escherichia coli to study its possible function under stress conditions. Upon transfer from 37°C to 50°C, a temperature known to cause cell autolysis, those cells that accumulated CsHSP17.5 showed improved viability compared with control cultures. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of cell lysates suggested that such a protective effect in vivo is due to the ability of recombinant sHSP to maintain soluble cytosolic proteins in their native conformation, with little substrate specificity. To test the recent hypothesis that sHSPs may be involved in protection against cold stress, we also studied the viability of recombinant cells at 4°C. Unlike the major heat-induced chaperone, GroEL/ES, the chestnut sHSP significantly enhanced cell survivability at this temperature. CsHSP17.5 thus represents an example of a HSP capable of protecting cells against both thermal extremes. Consistent with these findings, high-level induction of homologous transcripts was observed in vegetative tissues of chestnut plantlets exposed to either type of thermal stress but not salt stres

El Pino Canario: Un superviviente entre volcanes

El pino canario constituye una singularidad dentro del conjunto de pinos, ya que presenta una amplia gama de estrategias que permiten su persistencia y que han sido adquiridas a lo largo de su evolución en un ambiente volcánico. Todos los pinos son especies que presentan adaptaciones frente al fuego y de centran en dos estrategias: 1) una eficiente dispersión posincendio basada en una gran capacidad dispersiva y en la presencia de piñas serótinas; y 2) la resistencia individual, con cortezas gruesas que les permiten alcanzar gran longevidad

Restauración de las olmedas ibéricas (Ulmus minor y U. laevis) en zonas riparias de la Comunidad de Madrid

El proyecto LIFE+ “Olmos Vivos” (LIFE13 BIO/ES/000556) tiene como objetivo la restauración de unas formaciones vegetales, las olmedas, que por diversos motivos prácticamente han desaparecido del paisaje forestal español, a pesar de haber poseído un alto valor ecológico y cultural. La grafiosis ha constituido una de las enfermedades forestales más devastadoras, y supuso la práctica desaparición de las olmedas ibéricas de Ulmus minor . En el caso de Ulmus laevis , la alteración de su hábitat ligado a zonas temporalmente encharcadas y riberas ha provocado que las poblaciones españolas se encuentren en riesgo de desaparición. Gracias a la obtención de siete clones de U. minor resistentes a la grafiosis como fruto del Programa del Olmo (UPM-MAGRAMA), el presente proyecto permitirá reintroducir la especie en diversas localizaciones de ribera de los ríos Jarama y Tajo. Asimismo, se plantarán brinzales obtenidos de agrupaciones relícticas de U. laevis , con el fin de aumentar sus poblaciones y conservar sus recursos genéticos, en terrenos de naturaleza silícea de las riberas del río Jarama y Arroyo Viñuelas. El desarrollo del proyecto, de cinco años y tres meses de duración 2014-2019), prevé la plantación de unas 16 700 plantas. Al mismo tiempo se recuperará en nuestras ciudades y pueblos la presencia del olmo, mediante plantaciones con fines divulgativos en entornos urbanos y paseos históricos, para devolver así el protagonismo cultural a un árbol que siempre estuvo entre nosotros, presidiendo las reuniones en las plazas y acompañando con su sombra en muchos caminos de nuestra geografía

Proteínas sHSP del castaño común (Castanea sativa Mill.) : aspectos moleculares de la respuesta al estrés abiótico

En esta tesis doctoral se refiere la caracterización de una proteína de choque térmico de bajo peso molecular abundante en la semilla del castaño común, denominada Cs HSP17.5, perteneciente a la clase I citosólica. Por primera vez para una proteína de este tipo se ha demostrado su presencia constitutiva en el tallo, principalmente en el cambium y floema secundario. Se ha estudiado su expresión a lo largo de la maduración y germinación de la semilla. Así como en órganos vegetativos de plántulas sometidas a estrés controlado. Se ha mostrado que las temperaturas altas (32 y 40ºC) y bajas (4ºC) inducen la expresión de la citada proteína. Se ha caracterizado su actividad in vitro como chaperona molecular, empleando como sustrato la endoquitinasa Cs Ch1 de la semilla de castaño. Se ha expresado de manera estable en E.coli, demostrándose además que Cs HSP17.5 confiere una protección frente a las temperaturas extremas, tanto altas (50ºC) como bajas (4ºC). Este último resultado es la primera evidencia experimental de una protección frente al frío ejercida por una proteína de esta clase

Simulation analysis suggest Quercus suber x Quercus ilex hybridization could be underestimated

Analisis de la ifiabilidad de estimaciones previas de la tasa de hibridacion entre encinas y alcornoques

Variabilidad genética y gestión forestal

La diversidad biológica, su conservación e incremento, es uno de los principios básicos de la gestión forestal sostenible. La alta variabilidad genética de las especies forestales es responsable de los procesos de adaptación ante factores bióticos y abióticos extremos que, a su vez, aseguran la persistencia frente a los riesgos a los que están sometidas las masas forestales. En este trabajo se analizan distintos aspectos relacionados con la variabilidad genética de las especies forestales, y como la gestión forestal influye sobre ella. Se analiza la variabilidad entre poblaciones (que es una de las bases de la comercialización de material forestal de reproducción), la influencia del sistema de reproducción en la variabilidad genética de las masas y los efectos en ellas de los tratamientos selvícolas, así como la variación individual y clonal aprovechada en los programas de selección. Por último, se analiza el papel de la variabilidad genética en los programas de mejora y conservación de recursos genéticos forestales