Dehydrins in maritime pine (Pinus pinaster) and their expression related to drought stress response

Maritime pine (Pinus pinaster) is an important commercial species throughout its Atlantic distribution. With the anticipated increase in desiccation of its habitat as a result of climate change, the selection of genotypes with increased survival and growth capability under these conditions for breeding programs is of great interest for this species. We aimed to study the response to a realistic drought stress under controlled conditions, looked for a method to measure dehydration resistance, and analyzed dehydrin expression in drought-resistant and drought-sensitive clones from different ecotypes. We report here the sequence characteristics and the expression patterns of five dehydrins from P. pinaster, along with the physiological characterization of drought stress responses in different genotypes (clonally replicated plants), originating from a broad geographical distribution across France and Spain (provenances). In total, we distinguished five different dehydrin genes in silico, grouped into two types—K2 and SKn. Three of the dehydrin genes had several sequence variants, differing by multiple or single amino acid substitutions. Only two of the dehydrins (PpinDhn3 and PpinDhn4) showed an increase in transcription with increased drought stress which was dependent on provenance and genotype, suggesting their involvement in drought resistance. The other dehydrins showed decreased expression trends with increased severity of the drought stress. The lack of close association between the drought stress and expression patterns of these dehydrin genes suggest that they could have other functions and not be involved in drought resistance. Our results suggest large differences in function between different dehydrin genes

Variación en asignación reproductiva temprana en ensayos multi-localidad de pino carrasco y pino negral

Life histories in Mediterranean pines are well known to be closely related to different fire and disturbance regimes. Variation in these factors is also reflected in reproductive strategies at the specific and intraspecific level. Specifically, the onset of reproduction is a crucial stage for any organism because it has profound implications on fitness. In this paper we focus on the intraspecific variation and plasticity in the threshold size for reproduction and reproductive allocation in two Mediterranean pines, assessed at the onset of reproduction, when trade-offs between reproduction and growth are expected to be greater. Replicated common garden provenance and progeny trials of Aleppo pine and Maritime pine were used to estimate genetic parameters for reproduction and vegetative growth, as well as variation in plasticity in reproductive strategies at the intraspecific level. In both species, high variation among populations was found for both threshold size for reproduction and for reproductive allocation. Reproductive allocation was also highly variable within populations and showed moderate to high values of heritability and high coefficients of additive genetic variation. These results indicate a high genetic control of these reproductive traits, while high additive genetic variation is maintained, allowing to face selective pressures. Moreover, reproductive strategies although plastic, showed low genotype × environment interaction, and intraspecific variation was highly consistent across trial sites both at the population and the family levels. The former data confirm the strong genetic control of reproductive traits in these species. Finally, the fact that Aleppo pine starts its reproductive phase as female while Maritime pine can start reproducing either as male or female deserves further attention.Las estrategias de historia vital en pinos mediterráneos están estrechamente ligadas a diversos regímenes de incendios y perturbaciones. A su vez, la variabilidad de esos factores también se ve reflejada en las estrategias reproductivas a niveles inter e intraespecíficos. Concretamente, el comienzo de la reproducción es una etapa crucial para cualquier organismo debido a su profunda influencia en su adaptación al medio. Este trabajo se enfoca en el estudio de la variabilidad intraespecífica y la plasticidad en el tamaño umbral de reproducción y la asignación reproductiva en dos pinos mediterráneos. El estudio se realizó durante el comienzo de la fase reproductiva, momento en que se estima que la compensación entre reproducción y crecimiento es de mayor importancia. Se utilizaron ensayos multi-sitio de procedencias y progenies de pino carrasco y pino negral para estimar los parámetros genéticos de caracteres reproductivos y de crecimiento vegetativo, así como para conocer la variabilidad en la plasticidad de las estrategias reproductivas a nivel intraespecífico. En ambas especies se halló una alta variabilidad entre poblaciones para el tamaño umbral de reproducción y para la asignación reproductiva. La asignación reproductiva también fue altamente variable dentro de poblaciones y mostró valores de heredabilidad de moderados a altos y altos coeficientes de varianza genética aditiva. Estos resultados indican un alto control genético de los rasgos reproductivos, mientras se mantiene una alta varianza genética, permitiendo afrontar futuras presiones selectivas. Además, a pesar de la existencia de plasticidad en las estrategias reproductivas, éstas mostraron una baja interacción genotipo × ambiente, y la variación intraespecífica fue acorde en los diferentes lugares de ensayo tanto a nivel poblacional como familiar. Los datos anteriores confirman el alto control genético de los rasgos reproductivos en estas especies. Finalmente, el hecho de que el pino carrasco comience su fase reproductora como hembra mientras que el pino negral pueda comenzar su reproducción bien como macho o bien como hembra, merece una atención más detallada.This research was developed as part of projects AT07-002 and INIA-RTA07-100 of INIA and PSS-310000-2008-4 of the Spanish Ministry of Science and Innovation. Genetic trials reported in this paper form part of Genfored network of forest genetic trials in Spain, implemented mainly through project CC03-048 (DGB-INIA agreement). PMER and PCAV trials were installed as part of project TREESNIPS (QLK3-CT2002-01973). PRIA and PREB trials were established under the Genetic Breeding Program of Galicia by the Centro de Investigación Forestal de Lourizán. Luis Santos is supported by the Spanish Ministry of Education via a doctoral grant (FPU AP-2007-03302

Cyclophilins A and B oppositely regulate renal tubular epithelial cell phenotype

Altres ajuts: E.S. and M.D. were supported by the generous contribution of Asdent Patients Association. This work was supported in part by grants from Ministerio de Ciencia e Innovación, the Fundación Senefro (SEN2019 to A.M.), and Red de Investigación Renal REDinREN (12/0021/0013). K.A.N. is supported by National Institutes of Health (NIH) DK 47060. A.M. group holds the Quality Mention from the Generalitat de Catalunya.Restoration of kidney tubular epithelium following sublethal injury sequentially involves partial epithelial-mesenchymal transition (pEMT), proliferation, and further redifferentiation into specialized tubule epithelial cells (TECs). Because the immunosuppressant cyclosporine-A produces pEMT in TECs and inhibits the peptidyl-prolyl isomerase (PPIase) activity of cyclophilin (Cyp) proteins, we hypothesized that cyclophilins could regulate TEC phenotype. Here we demonstrate that in cultured TECs, CypA silencing triggers loss of epithelial features and enhances transforming growth factor β (TGF β)-induced EMT in association with upregulation of epithelial repressors Slug and Snail. This pro-epithelial action of CypA relies on its PPIase activity. By contrast, CypB emerges as an epithelial repressor, because CypB silencing promotes epithelial differentiation, prevents TGF β -induced EMT, and induces tubular structures in 3D cultures. In addition, in the kidneys of CypB knockout mice subjected to unilateral ureteral obstruction, inflammatory and pro-fibrotic events were attenuated. CypB silencing/knockout leads to Slug, but not Snail, downregulation. CypB support of Slug expression depends on its endoplasmic reticulum location, where it interacts with calreticulin, a calcium-buffering chaperone related to Slug expression. As CypB silencing reduces ionomycin-induced calcium release and Slug upregulation, we suggest that Slug expression may rely on CypB modulation of calreticulin-dependent calcium signaling. In conclusion, this work uncovers new roles for CypA and CypB in modulating TEC plasticity and identifies CypB as a druggable target potentially relevant in promoting kidney repair

Polygenic adaptation and negative selection across traits, years and environments in a long-lived plant species (Pinus pinaster Ait., Pinaceae)

17 Pág.A decade of genetic association studies in multiple organisms suggests that most complex traits are polygenic; that is, they have a genetic architecture determined by numerous loci, each with small effect-size. Thus, determining the degree of polygenicity and its variation across traits, environments and time is crucial to understand the genetic basis of phenotypic variation. We applied multilocus approaches to estimate the degree of polygenicity of fitness-related traits in a long-lived plant (Pinus pinaster Ait., maritime pine) and to analyse this variation across environments and years. We evaluated five categories of fitness-related traits (survival, height, phenology, functional, and biotic-stress response) in a clonal common-garden network planted in contrasted environments (over 20,500 trees). Most of the analysed traits showed evidence of local adaptation based on Qst -Fst comparisons. We further observed a remarkably stable degree of polygenicity, averaging 6% (range of 0%-27%), across traits, environments and years. We detected evidence of negative selection, which could explain, at least partially, the high degree of polygenicity. Because polygenic adaptation can occur rapidly, our results suggest that current predictions on the capacity of natural forest tree populations to adapt to new environments should be revised, especially in the current context of climate change.This study was funded by the Spanish Ministry of Economy and Competitiveness through projects RTA2010-00120-C02- 02 (CLONAPIN), CGL2011-30182- C02- 01 (AdapCon) and AGL2012-40151- C03- 02 (FENOPIN). The study was also supported by the “Initiative d’Excellence (IdEx) de l’Université de Bordeaux - Chaires d'installation 2015” (EcoGenPin) and the European Union's Horizon 2020 research and innovation programme under grant agreement No 773383 (B4EST)Peer reviewe

Increased IKKα Expression in the Basal Layer of the Epidermis of Transgenic Mice Enhances the Malignant Potential of Skin Tumors

Non-melanoma skin cancer is the most frequent type of cancer in humans. In this study we demonstrate that elevated IKKα expression in murine epidermis increases the malignancy potential of skin tumors. We describe the generation of transgenic mice overexpressing IKKα in the basal, proliferative layer of the epidermis and in the outer root sheath of hair follicles. The epidermis of K5-IKKα transgenic animals shows several alterations such as hyperproliferation, mislocalized expression of integrin-α6 and downregulation of the tumor suppressor maspin. Treatment of the back skin of mice with the mitogenic agent 12-O-tetradecanoylphorbol-13-acetate causes in transgenic mice the appearance of different preneoplastic changes such as epidermal atypia with loss of cell polarity and altered epidermal tissue architecture, while in wild type littermates this treatment only leads to the development of benign epidermal hyperplasia. Moreover, in skin carcinogenesis assays, transgenic mice carrying active Ha-ras (K5-IKKα-Tg.AC mice) develop invasive tumors, instead of the benign papillomas arising in wild type-Tg-AC mice also bearing an active Ha-ras. Therefore we provide evidence for a tumor promoter role of IKKα in skin cancer, similarly to what occurs in other neoplasias, including hepatocarcinomas and breast, prostate and colorectal cancer. The altered expression of cyclin D1, maspin and integrin-α6 in skin of transgenic mice provides, at least in part, the molecular bases for the increased malignant potential found in the K5-IKKα skin tumors