12 research outputs found

    Juniperus L. for Restoration of Degraded Forest Lands in Turkey

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    Degraded forests are among of the most important environmental and commercial problems around the world. Turkey has 22.74 million hectares of forest area, out of which 9.656 million ha (42%) are unproductive. To transform these unproductive forests into productive ones, forest restoration including rehabilitation is one of the best actions. In this sense, juniper species play an important role for degraded lands because they are drought-tolerant and withstand aridity and poor soils better than most timber species grown in Turkey. Therefore, this review presents the ecological considerations for the restoration of degraded forest lands in Turkey under the conditions of climate change. Within this framework, it focuses on the production of planting stock of juniper species, the significance of site-species matching, and post-planting site maintenance for successful rehabilitation

    Polyploidy in the Conifer Genus Juniperus: An Unexpectedly High Rate

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    Recent research suggests that the frequency of polyploidy may have been underestimated in gymnosperms. One notable example is in the conifer genus Juniperus, where there are already a few reports of polyploids although data are still missing for most species. In this study, we evaluated the extent of polyploidy in Juniperus by conducting the first comprehensive screen across nearly all of the genus. Genome size data from fresh material, together with chromosome counts, were used to demonstrate that genome sizes estimated from dried material could be used as reliable proxies to uncover the extent of ploidy diversity across the genus. Our analysis revealed that 16 Juniperus taxa were polyploid, with tetraploids and one hexaploid being reported. Furthermore, by analyzing the genome size and chromosome data within a phylogenetic framework we provide the first evidence of possible lineage-specific polyploidizations within the genus. Genome downsizing following polyploidization is moderate, suggesting limited genome restructuring. This study highlights the importance of polyploidy in Juniperus, making it the first conifer genus and only the second genus in gymnosperms where polyploidy is frequent. In this sense, Juniperus represents an interesting model for investigating the genomic and ecological consequences of polyploidy in conifers

    Evolutionary history of two rare endemic conifer species from the eastern Qinghai-Tibet plateau

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    BACKGROUND AND AIMS: Understanding the population genetics and evolutionary history of endangered species is urgently needed in an era of accelerated biodiversity loss. This knowledge is most important for regions with high endemism that are ecologically vulnerable, such as the Qinghai–Tibet Plateau (QTP). METHODS: The genetic variation of 84 juniper trees from six populations of Juniperus microsperma and one population of Juniperus erectopatens, two narrow-endemic junipers from the QTP that are sister to each other, was surveyed using RNA-sequencing data. Coalescent-based analyses were used to test speciation, migration and demographic scenarios. Furthermore, positively selected and climate-associated genes were identified, and the genetic load was assessed for both species. KEY RESULTS: Analyses of 149 052 single nucleotide polymorphisms showed that the two species are well differentiated and monophyletic. They diverged around the late Pliocene, but interspecific gene flow continued until the Last Glacial Maximum. Demographic reconstruction by Stairway Plot detected two severe bottlenecks for J. microsperma but only one for J. erectopatens. The identified positively selected genes and climate-associated genes revealed habitat adaptation of the two species. Furthermore, although J. microsperma had a much wider geographical distribution than J. erectopatens, the former possesses lower genetic diversity and a higher genetic load than the latter. CONCLUSIONS: This study sheds light on the evolution of two endemic juniper species from the QTP and their responses to Quaternary climate fluctuations. Our findings emphasize the importance of speciation and demographic history reconstructions in understanding the current distribution pattern and genetic diversity of threatened species in mountainous regions

    Tapping into non-English-language science for the conservation of global biodiversity.

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    The widely held assumption that any important scientific information would be available in English underlies the underuse of non-English-language science across disciplines. However, non-English-language science is expected to bring unique and valuable scientific information, especially in disciplines where the evidence is patchy, and for emergent issues where synthesising available evidence is an urgent challenge. Yet such contribution of non-English-language science to scientific communities and the application of science is rarely quantified. Here, we show that non-English-language studies provide crucial evidence for informing global biodiversity conservation. By screening 419,679 peer-reviewed papers in 16 languages, we identified 1,234 non-English-language studies providing evidence on the effectiveness of biodiversity conservation interventions, compared to 4,412 English-language studies identified with the same criteria. Relevant non-English-language studies are being published at an increasing rate in 6 out of the 12 languages where there were a sufficient number of relevant studies. Incorporating non-English-language studies can expand the geographical coverage (i.e., the number of 2° × 2° grid cells with relevant studies) of English-language evidence by 12% to 25%, especially in biodiverse regions, and taxonomic coverage (i.e., the number of species covered by the relevant studies) by 5% to 32%, although they do tend to be based on less robust study designs. Our results show that synthesising non-English-language studies is key to overcoming the widespread lack of local, context-dependent evidence and facilitating evidence-based conservation globally. We urge wider disciplines to rigorously reassess the untapped potential of non-English-language science in informing decisions to address other global challenges. Please see the Supporting information files for Alternative Language Abstracts

    Genetic exploration of polyploidy in the genus Juniperus (Cupressaceae)

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    La polyploïdie est un processus important et un moteur de la diversification et de l'évolution des plantes. Peu de polyploïdes naturels ont été décrits chez Juniperus, un genre de conifère représenté par 75 espèces d'arbres ou arbustes à feuilles persistantes, largement réparties dans l'hémisphère nord. Dans ce travail de recherche, l’implication de la polyploïdie dans l'évolution de Juniperus et l’élucidation des mécanismes sous-jacents à ces événements de polyploïdisation sont explorées. La taille du génome (TG) et le niveau de ploïdie ont été évalués chez 111/115 taxons en utilisant la cytométrie en flux et les comptages chromosomiques. Le taux de polyploïdie chez les genévriers s’est avéré être exceptionnellement élevé : 15 taxons sont des tétraploïdes et un seul taxon (J. foetidissima) est hexaploïde. Juniperus foetidissima représente le seul conifère hexaploïde découvert à ce jour à part Sequoia sempervirens. Nous avons également utilisé des approches de modélisation phylogénétique pour déterminer la TG ancestrale dans les trois clades de Juniperus et pour reconstruire le processus évolutif de la polyploïdisation chez ce genre. Au moins 10 événements de polyploïdisation ont eu lieu au cours de l'évolution et de la diversification de Juniperus. Nous avons ensuite exploré l’origine de la polyploïdie chez certaines espèces méditerranéennes. La variation de la TG et le niveau de ploïdie de deux variétés de J. sabina ont été estimés : Les populations échantillonnées de J. sabina var. sabina se sont avérées être diploïdes, tandis que les populations de J. sabina var. balkanensis étaient toutes tétraploïdes. Ces derniers auraient été issus d'une ancienne hybridation entre le tétraploïde J. thurifera et le diploïde J. sabina. Dans les Alpes françaises, où J. sabina var. sabina et J. thurifera sont en sympatrie, des individus présentant des morphologies intermédiaires entre ces deux espèces sont observés. Suite à des estimations des TG, de séquençage des ITS et de régions chloroplastiques, ces individus sont considérés comme des hybrides triploïdes. Enfin, l’utilisation des marqueurs AFLP pour déchiffrer les relations phylogénétiques entre des espèces méditerranéenne a montré que plusieurs pools génétiques contribuent à la diversité de Juniperus. Aussi ces marqueurs ont contribué à la découverte des contributions de ces pools génétiques aux taxons polyploïdes. Alors que les populations libanaises de l'hexaploïde J. foetidissima sont issues d'une lignée ancestrale unique, la population grecque semble résulter d'un mélange inégal de deux lignées anciennes. Ces deux lignées contribuent également au tétraploïde J. thurifera. Cette analyse a également montré que l’espèce méditerranéenne J. excelsa et l’espèce africaine J. procera partagent la même lignée ancestrale. Cependant, des analyses supplémentaires sont nécessaires pour une interprétation plus complète des données. L'importance de l'hybridation interspécifique et de la polyploïdie dans l'évolution des espèces de Juniperus nécessite d’amples recherches visant à comprendre le lien entre ces mécanismes et l'adaptation de ces espèces à un large spectre d'habitats extrêmes. Ces recherches futures devraient aussi contribuer à découvrir comment les espèces de conifères peuvent s’adapter aux changements climatiques.Polyploidy is considered as an important phenomenon and a key driving force for plant diversification and evolution. Few natural polyploid species have been described in Juniperus, a coniferous genus represented by 75 species of evergreen trees or shrubs widely distributed in the North Hemisphere. The occurrence of polyploidy in the evolution of this genus as well as a more comprehensive view of pathways that were involved in these polyploidization events are explored in this research work. Genome size (GS) and ploidy level assessments were conducted on 111/115 taxa using flow-cytometry and chromosome counts. Juniperus holds an exceptionally high rate of polyploidy, 15 taxa being tetraploids and just one (J. foetidissima) being hexaploid. It represents the only hexaploid conifer discovered to date after Sequoia sempervirens. We also used phylogenetically-informed trait evolution modelling approaches to determine ancestral GS in the three clades of Juniperus and to reconstruct the evolutionary process of polyploidization in Juniperus. At least 10 polyploidization events have occurred during Juniperus evolution and diversification. We then explored the origin of polyploidy in selected Mediterranean species. The GS variation and the ploidy level of two J. sabina varieties were estimated: J. sabina var. sabina sampled populations were shown to be diploid, while J. sabina var. balkanensis populations were all tetraploid. The latter has been postulated to have arisen from an ancient hybridization between the tetraploid J. thurifera and the diploid J. sabina. In the French Alps, where J. sabina var. sabina and J. thurifera occur in sympatry, individuals with intermediate morphologies between these two species are observed. Evidences based on GS assessments, ITS and chloroplastic sequences demonstrated these individuals as triploid hybrids. Finally, the use of AFLP markers to decipher phylogenetic relationships between Mediterranean and Eastern Mediterranean species showed that multiple lineages contributes to Juniperus diversity and shed light on some polyploid taxa origins. While the Lebanese populations of the hexaploid J. foetidissima are issued from a unique ancestral lineage, the Greek population seems to be the result of an unequal admixture of two ancient lineages. These two lineages contribute also to the tetraploid J. thurifera. This analysis showed also that the Mediteranean J. excelsa and the African taxa J. procera shares the same ancestral lineage. However, further analyses are needed for a more complete interpretation of the data. The importance of interspecific hybridization and of polyploidization in the evolution of Juniperus species argues in favor of the development of researches aiming at understanding the link between these mechanisms and the adaptation of those species to a wide range of extreme habitats. Such future researches should contribute to predict how conifer species may adapt to dramatic changes in the Earth’s climate

    Exploration génétique de la polyploïdie du genre Juniperus (Cupressaceae)

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    Polyploidy is considered as an important phenomenon and a key driving force for plant diversification and evolution. Few natural polyploid species have been described in Juniperus, a coniferous genus represented by 75 species of evergreen trees or shrubs widely distributed in the North Hemisphere. The occurrence of polyploidy in the evolution of this genus as well as a more comprehensive view of pathways that were involved in these polyploidization events are explored in this research work. Genome size (GS) and ploidy level assessments were conducted on 111/115 taxa using flow-cytometry and chromosome counts. Juniperus holds an exceptionally high rate of polyploidy, 15 taxa being tetraploids and just one (J. foetidissima) being hexaploid. It represents the only hexaploid conifer discovered to date after Sequoia sempervirens. We also used phylogenetically-informed trait evolution modelling approaches to determine ancestral GS in the three clades of Juniperus and to reconstruct the evolutionary process of polyploidization in Juniperus. At least 10 polyploidization events have occurred during Juniperus evolution and diversification. We then explored the origin of polyploidy in selected Mediterranean species. The GS variation and the ploidy level of two J. sabina varieties were estimated: J. sabina var. sabina sampled populations were shown to be diploid, while J. sabina var. balkanensis populations were all tetraploid. The latter has been postulated to have arisen from an ancient hybridization between the tetraploid J. thurifera and the diploid J. sabina. In the French Alps, where J. sabina var. sabina and J. thurifera occur in sympatry, individuals with intermediate morphologies between these two species are observed. Evidences based on GS assessments, ITS and chloroplastic sequences demonstrated these individuals as triploid hybrids. Finally, the use of AFLP markers to decipher phylogenetic relationships between Mediterranean and Eastern Mediterranean species showed that multiple lineages contributes to Juniperus diversity and shed light on some polyploid taxa origins. While the Lebanese populations of the hexaploid J. foetidissima are issued from a unique ancestral lineage, the Greek population seems to be the result of an unequal admixture of two ancient lineages. These two lineages contribute also to the tetraploid J. thurifera. This analysis showed also that the Mediteranean J. excelsa and the African taxa J. procera shares the same ancestral lineage. However, further analyses are needed for a more complete interpretation of the data. The importance of interspecific hybridization and of polyploidization in the evolution of Juniperus species argues in favor of the development of researches aiming at understanding the link between these mechanisms and the adaptation of those species to a wide range of extreme habitats. Such future researches should contribute to predict how conifer species may adapt to dramatic changes in the Earth’s climate.La polyploïdie est un processus important et un moteur de la diversification et de l'évolution des plantes. Peu de polyploïdes naturels ont été décrits chez Juniperus, un genre de conifère représenté par 75 espèces d'arbres ou arbustes à feuilles persistantes, largement réparties dans l'hémisphère nord. Dans ce travail de recherche, l’implication de la polyploïdie dans l'évolution de Juniperus et l’élucidation des mécanismes sous-jacents à ces événements de polyploïdisation sont explorées. La taille du génome (TG) et le niveau de ploïdie ont été évalués chez 111/115 taxons en utilisant la cytométrie en flux et les comptages chromosomiques. Le taux de polyploïdie chez les genévriers s’est avéré être exceptionnellement élevé : 15 taxons sont des tétraploïdes et un seul taxon (J. foetidissima) est hexaploïde. Juniperus foetidissima représente le seul conifère hexaploïde découvert à ce jour à part Sequoia sempervirens. Nous avons également utilisé des approches de modélisation phylogénétique pour déterminer la TG ancestrale dans les trois clades de Juniperus et pour reconstruire le processus évolutif de la polyploïdisation chez ce genre. Au moins 10 événements de polyploïdisation ont eu lieu au cours de l'évolution et de la diversification de Juniperus. Nous avons ensuite exploré l’origine de la polyploïdie chez certaines espèces méditerranéennes. La variation de la TG et le niveau de ploïdie de deux variétés de J. sabina ont été estimés : Les populations échantillonnées de J. sabina var. sabina se sont avérées être diploïdes, tandis que les populations de J. sabina var. balkanensis étaient toutes tétraploïdes. Ces derniers auraient été issus d'une ancienne hybridation entre le tétraploïde J. thurifera et le diploïde J. sabina. Dans les Alpes françaises, où J. sabina var. sabina et J. thurifera sont en sympatrie, des individus présentant des morphologies intermédiaires entre ces deux espèces sont observés. Suite à des estimations des TG, de séquençage des ITS et de régions chloroplastiques, ces individus sont considérés comme des hybrides triploïdes. Enfin, l’utilisation des marqueurs AFLP pour déchiffrer les relations phylogénétiques entre des espèces méditerranéenne a montré que plusieurs pools génétiques contribuent à la diversité de Juniperus. Aussi ces marqueurs ont contribué à la découverte des contributions de ces pools génétiques aux taxons polyploïdes. Alors que les populations libanaises de l'hexaploïde J. foetidissima sont issues d'une lignée ancestrale unique, la population grecque semble résulter d'un mélange inégal de deux lignées anciennes. Ces deux lignées contribuent également au tétraploïde J. thurifera. Cette analyse a également montré que l’espèce méditerranéenne J. excelsa et l’espèce africaine J. procera partagent la même lignée ancestrale. Cependant, des analyses supplémentaires sont nécessaires pour une interprétation plus complète des données. L'importance de l'hybridation interspécifique et de la polyploïdie dans l'évolution des espèces de Juniperus nécessite d’amples recherches visant à comprendre le lien entre ces mécanismes et l'adaptation de ces espèces à un large spectre d'habitats extrêmes. Ces recherches futures devraient aussi contribuer à découvrir comment les espèces de conifères peuvent s’adapter aux changements climatiques

    Juniperus L. for Restoration of Degraded Forest Lands in Turkey

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    Polyploidy in the Conifer Genus Juniperus: An Unexpectedly High Rate

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    International audienceRecent research suggests that the frequency of polyploidy may have been underestimated in gymnosperms. One notable example is in the conifer genus Juniperus, where there are already a few reports of polyploids although data are still missing for most species. In this study, we evaluated the extent of polyploidy in Juniperus by conducting the first comprehensive screen across nearly all of the genus. Genome size data from fresh material, together with chromosome counts, were used to demonstrate that genome sizes estimated from dried material could be used as reliable proxies to uncover the extent of ploidy diversity across the genus. Our analysis revealed that 16 Juniperus taxa were polyploid, with tetraploids and one hexaploid being reported. Furthermore, by analyzing the genome size and chromosome data within a phylogenetic framework we provide the first evidence of possible lineage-specific polyploidizations within the genus. Genome downsizing following polyploidization is moderate, suggesting limited genome restructuring. This study highlights the importance of polyploidy in Juniperus, making it the first conifer genus and only the second genus in gymnosperms where polyploidy is frequent. In this sense, Juniperus represents an interesting model for investigating the genomic and ecological consequences of polyploidy in conifers

    The evolution of the hypotetraploid Catolobus pendulus genome – the poorly known sister species of Capsella

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    The establishment of Arabidopsis as the most important plant model has also brought other crucifer species into the spotlight of comparative research. While the genus Capsella has become a prominent crucifer model system, its closest relative has been overlooked. The unispecific genus Catolobus is native to temperate Eurasian woodlands, from eastern Europe to the Russian Far East. Here, we analyzed chromosome number, genome structure, intraspecific genetic variation, and habitat suitability of Catolobus pendulus throughout its range. Unexpectedly, all analyzed populations were hypotetraploid (2n = 30, ~330 Mb). Comparative cytogenomic analysis revealed that the Catolobus genome arose by a whole-genome duplication in a diploid genome resembling Ancestral Crucifer Karyotype (ACK, n = 8). In contrast to the much younger Capsella allotetraploid genomes, the presumably autotetraploid Catolobus genome (2n = 32) arose early after the Catolobus/Capsella divergence. Since its origin, the tetraploid Catolobus genome has undergone chromosomal rediploidization, including a reduction in chromosome number from 2n = 32 to 2n = 30. Diploidization occurred through end-to-end chromosome fusion and other chromosomal rearrangements affecting a total of six of 16 ancestral chromosomes. The hypotetraploid Catolobus cytotype expanded toward its present range, accompanied by some longitudinal genetic differentiation. The sister relationship between Catolobus and Capsella allows comparative studies of tetraploid genomes of contrasting ages and different degrees of genome diploidization

    Polyploidy in Cupressaceae: Discovery of a new naturally occurring tetraploid, Xanthocyparis vietnamensis

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    While polyploidy (whole-genome multiplication) is generally considered rare in extant gymnosperms (with the exception of Ephedra, Ephedraceae), the occurrence of sporadic polyploid individuals belonging to various genera in the conifer family Cupressaceae has been reported in the literature. In addition, recent studies have revealed that polyploidy is not uncommon in the genus Juniperus (Cupressaceae), with tetraploid and hexaploid individuals reported in individuals collected from wild populations. Given these findings, we undertook a comprehensive screening of ploidy levels in 32 species belonging to the four genera that are phylogenetically closest to Juniperus (i.e., Callitropsis, Hesperocyparis, Xanthocyparis, and Cupressus), referred to as the CaHXCu complex. In addition, we also determined the ploidy level of two accessions in the poorly studied tetraploid, Fitzroya cupressoides. Using flow cytometry together with published chromosome counts to assign ploidy levels, we show that all species of the CaHXCu complex are diploid except Xanthocyparis vietnamensis, which is tetraploid, with a genome size of 44.60¿pg/2¿C. This study opens up new opportunities for studying the impact and consequences of polyploidy on the evolution and adaptation of species in Cupressaceae.This research was supported in part by funds to RPA from project 0324512, Baylor University1 Introduction 2 Material and Methods 2.1 Plant material 2.2 Genome size assessment and ploidy level determination 3 Results 3.1 Ploidy level screening of species belonging to the CaHXCu complex 3.2 Genome size assessment of Xanthocyparis vietnamensis 4 Discussion 4.1 Novel tetraploid uncovered in Cupressaceae—the endemic Xanthocyparis vietnamensis 4.2 Polyploidy in Cupressaceae 5 Conclusion Acknowledgement
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