Genetic background of juniper (Juniperus spp.) consumption predicted by fecal near-infrared spectroscopy in divergently selected goats raised in harsh rangeland environments.

BACKGROUND: Junipers (Juniperus spp.) are woody native, invasive plants that have caused encroachment problems in the U.S. western rangelands, decreasing forage productivity and biodiversity. A potential solution to this issue is using goats in targeted grazing programs. However, junipers, which grow in dry and harsh environmental conditions, use chemical defense mechanisms to deter herbivores. Therefore, genetically selecting goats for increased juniper consumption is of great interest for regenerative rangeland management. In this context, the primary objectives of this study were to: 1) estimate variance components and genetic parameters for predicted juniper consumption in divergently selected Angora (ANG) and composite Boer x Spanish (BS) goat populations grazing on Western U.S. rangelands; and 2) to identify genomic regions, candidate genes, and biological pathways associated with juniper consumption in these goat populations. RESULTS: The average juniper consumption was 22.4% (± 18.7%) and 7.01% (± 12.1%) in the BS and ANG populations, respectively. The heritability estimates (realized heritability within parenthesis) for juniper consumption were 0.43 ± 0.02 (0.34 ± 0.06) and 0.19 ± 0.03 (0.13 ± 0.03) in BS and ANG, respectively, indicating that juniper consumption can be increased through genetic selection. The repeatability values of predicted juniper consumption were 0.45 for BS and 0.28 for ANG. A total of 571 significant SNP located within or close to 231 genes in BS, and 116 SNP related to 183 genes in ANG were identified based on the genome-wide association analyses. These genes are primarily associated with biological pathways and gene ontology terms related to olfactory receptors, intestinal absorption, and immunity response. CONCLUSIONS: These findings suggest that juniper consumption is a heritable trait of polygenic inheritance influenced by multiple genes of small effects. The genetic parameters calculated indicate that juniper consumption can be genetically improved in both goat populations.

Phylogenomic analysis reveals the evolutionary history of Paleartic needle-leaved junipers.

Needle-leaved junipers (Juniperus sect. Juniperus, Cupressaceae) are coniferous trees and shrubs with red or blue fleshy cones. They are distributed across Asia, Macaronesia and the Mediterranean Basin, with one species (J. communis) having a circumboreal distribution. Here we aim to resolve the phylogeny of this clade to infer its intricate evolutionary history. To do so, we built a comprehensive, time-calibrated phylogeny using genotyping-by-sequencing (GBS) and combine it with species occurrence using phylogeographic tools. Our results provide solid phylogenetic resolution to propose a new taxonomic classification and a biogeographical history of the section. Specifically, we confirm the monophyly of two groups within J. sect. Juniperus: the Asian (blue-cone) species including the circumboreal J. communis, and the Mediterranean-Macaronesian (red-cone) species. In addition, we provide strong phylogenetic evidence for three distinct species (J. badia, J. conferta, J. lutchuensis) previously considered subspecies or varieties, as well as for the differentiation between the eastern and western Mediterranean lineages of J. macrocarpa. Our findings suggest that the Mediterranean basin was the primary center of diversification for Juniperus sect. Juniperus, followed by an East Asian-Tethyan disjunction resulting from uplifts of the Qinghai-Tibetan Plateau and climatic shifts. The colonization history of Macaronesia by red-cone junipers from the western Mediterranean appears to have taken place independently in two different geological periods: the Miocene (Azores) and the Pliocene (Madeira-Canary Islands). Overall, genomic data and phylogenetic analysis are key to consider a new taxonomic proposal and reconstruct the biogeographical history of the iconic needle-leaved junipers across the Paleartic.

Comparative transcriptome analysis of juniper branches infected by Gymnosporangium spp. highlights their different infection strategies associated with cytokinins.

BACKGROUND: Gymnosporangium asiaticum and G. yamadae can share Juniperus chinensis as the telial host, but the symptoms are completely different. The infection of G. yamadae causes the enlargement of the phloem and cortex of young branches as a gall, but not for G. asiaticum, suggesting that different molecular interaction mechanisms exist the two Gymnosporangium species with junipers. RESULTS: Comparative transcriptome analysis was performed to investigate genes regulation of juniper in responses to the infections of G. asiaticum and G. yamadae at different stages. Functional enrichment analysis showed that genes related to transport, catabolism and transcription pathways were up-regulated, while genes related to energy metabolism and photosynthesis were down-regulated in juniper branch tissues after infection with G. asiaticum and G. yamadae. The transcript profiling of G. yamadae-induced gall tissues revealed that more genes involved in photosynthesis, sugar metabolism, plant hormones and defense-related pathways were up-regulated in the vigorous development stage of gall compared to the initial stage, and were eventually repressed overall. Furthermore, the concentration of cytokinins (CKs) in the galls tissue and the telia of G. yamadae was significantly higher than in healthy branch tissues of juniper. As well, tRNA-isopentenyltransferase (tRNA-IPT) was identified in G. yamadae with highly expression levels during the gall development stages. CONCLUSIONS: In general, our study provided new insights into the host-specific mechanisms by which G. asiaticum and G. yamadae differentially utilize CKs and specific adaptations on juniper during their co-evolution.

Screening of Thiopeptide-Producing Streptomycetes Isolated From the Rhizosphere Soil of Juniperus excelsa.

The identification of an increasing number of drug-resistant pathogens has stimulated the development of new therapeutic agents to combat them. Microbial natural products are among the most important elements when it comes to drug discovery. Today, thiopeptide antibiotics are receiving increasing research attention due to their potent activity against Gram-positive bacteria. In this study, we demonstrated the successful use of a whole-cell microbial biosensor (Streptomyces lividans TK24 pMO16) for the specific detection of thiopeptide antibiotics among the native actinomycete strains isolated from the rhizosphere soil of Juniperus excelsa (Bieb.). Among the native strains, two strains of Streptomyces, namely sp. Je 1-79 and Je 1-613, were identified that were capable of producing thiopeptide antibiotics. A multilocus sequence analysis of five housekeeping genes (gyrB, atpD, recA, rpoB, and trpB) classified them as representatives of two different species of the genus Streptomyces. The thiopeptide antibiotics berninamycin A and B were identified in the extracts of the two strains by means of a dereplication analysis. The berninamycin biosynthetic gene cluster was also detected in the genome of the Streptomyces sp. Je 1-79 strain and showed a high level of similarity (93%) with the ber cluster from S. bernensis. Thus, the use of this whole-cell biosensor during the first stage of the screening process could serve to accelerate the specific detection of thiopeptide antibiotics.

Genome-wide RAD sequencing resolves the evolutionary history of serrate leaf Juniperus and reveals discordance with chloroplast phylogeny.

Juniper (Juniperus) is an ecologically important conifer genus of the Northern Hemisphere, the members of which are often foundational tree species of arid regions. The serrate leaf margin clade is native to topologically variable regions in North America, where hybridization has likely played a prominent role in their diversification. Here we use a reduced-representation sequencing approach (ddRADseq) to generate a phylogenomic data set for 68 accessions representing all 22 species in the serrate leaf margin clade, as well as a number of close and distant relatives, to improve understanding of diversification in this group. Phylogenetic analyses using three methods (SVDquartets, maximum likelihood, and Bayesian) yielded highly congruent and well-resolved topologies. These phylogenies provided improved resolution relative to past analyses based on Sanger sequencing of nuclear and chloroplast DNA, and were largely consistent with taxonomic expectations based on geography and morphology. Calibration of a Bayesian phylogeny with fossil evidence produced divergence time estimates for the clade consistent with a late Oligocene origin in North America, followed by a period of elevated diversification between 12 and 5 Mya. Comparison of the ddRADseq phylogenies with a phylogeny based on Sanger-sequenced chloroplast DNA revealed five instances of pronounced discordance, illustrating the potential for chloroplast introgression, chloroplast transfer, or incomplete lineage sorting to influence organellar phylogeny. Our results improve understanding of the pattern and tempo of diversification in Juniperus, and highlight the utility of reduced-representation sequencing for resolving phylogenetic relationships in non-model organisms with reticulation and recent divergence.

Gene flow between diploid and tetraploid junipers - two contrasting evolutionary pathways in two Juniperus populations.

BACKGROUND: Gene flow and polyploidy have been found to be important in Juniperus evolution. However, little evidence has been published elucidating the association of both phenomena in juniper taxa in the wild. Two main areas were studied in Spain (Eastern Iberian Range and Sierra de Baza) with both diploid and tetraploid taxa present in sympatry. Gene flow and ploidy level were assessed for these taxa and the resulted offspring. RESULTS: Twenty-two allo-triploid hybrids between J. sabina var. sabina and J. thurifera were found in the Eastern Iberian Range population. However, in the Sierra de Baza population no triploids were found. Instead, 18 allo-tetraploid hybrids between two tetraploid taxa: J. sabina var. balkanensis and J. thurifera were discovered. High genetic diversity was exhibited among the tetraploid hybrids at Sierra de Baza, in contrast to the genetically identical triploid hybrids at the Eastern Iberian Range; this suggests meiotic difficulties within the triploid hybrids. In addition, unidirectional gene flow was observed in both studied areas. CONCLUSION: Polyploidy and hybridization can be complementary partners in the evolution of Juniperus taxa in sympatric occurrences. Juniperus was shown to be an ideal coniferous model to study these two phenomena, independently or in concert.

Phylogenomic evidence for ancient recombination between plastid genomes of the Cupressus-Juniperus-Xanthocyparis complex (Cupressaceae).

BACKGROUND: Phylogenetic relationships among Eastern Hemisphere cypresses, Western Hemisphere cypresses, junipers, and their closest relatives are controversial, and generic delimitations have been in flux for the past decade. To address relationships and attempt to produce a more robust classification, we sequenced 11 new plastid genomes (plastomes) from the five variously described genera in this complex (Callitropsis, Cupressus, Hesperocyparis, Juniperus, and Xanthocyparis) and compared them with additional plastomes from diverse members of Cupressaceae. RESULTS: Phylogenetic analysis of protein-coding genes recovered a topology in which Juniperus is sister to Cupressus, whereas a tree based on whole plastomes indicated that the Callitropsis-Hesperocyparis-Xanthocyparis (CaHX) clade is sister to Cupressus. A sliding window analysis of site-specific phylogenetic support identified a ~ 15 kb region, spanning the genes ycf1 and ycf2, which harbored an anomalous signal relative to the rest of the genome. After excluding these genes, trees based on the remainder of the genes and genome consistently recovered a topology grouping the CaHX clade and Cupressus with strong bootstrap support. In contrast, trees based on the ycf1 and ycf2 region strongly supported a sister relationship between Cupressus and Juniperus. CONCLUSIONS: These results demonstrate that standard phylogenomic analyses can result in strongly supported but conflicting trees. We suggest that the conflicting plastomic signals result from an ancient introgression event involving ycf1 and ycf2 that occurred in an ancestor of this species complex. The introgression event was facilitated by plastomic recombination in an ancestral heteroplasmic individual carrying distinct plastid haplotypes, offering further evidence that recombination occurs between plastomes. Finally, we provide strong support for previous proposals to recognize five genera in this species complex: Callitropsis, Cupressus, Hesperocyparis, Juniperus, and Xanthocyparis.

Molecular approaches for the analysis of airborne pollen: A case study of Juniperus pollen.

BACKGROUND: Pollen monitoring is a common and vital tool in the field of allergy, creating awareness in pollen sensitive individuals. Traditionally, pollen monitoring has been based on conventional microscopic counting techniques that are labor intensive and limited in the identification to the genus or family level. Molecular techniques provide an alternative approach that is less labor intensive and enable identification of any species by its genetic fingerprint. OBJECTIVE: To use quantitative polymerase chain reaction (qPCR) to evaluate pollen concentrations in air samples. METHODS: Juniperus pollen was selected as our model because of the importance of this pollen in the southcentral United States. We analyzed 105 air samples collected with a Burkard spore trap from 2013 to 2015 using species-specific primers and probes. To evaluate the feasibility of a molecular approach, we used duplicate air samples that allowed us to compare results from classical identification based on light microscopy with our qPCR results. RESULTS: Pollen concentrations from the qPCR data were significantly correlated with concentrations determined through light microscopy (R = 0.902, P < .001). We also confirmed an overlap in the pollination seasons between Juniperus ashei and Juniperus pinchotii and between J ashei and Juniperus virginiana. CONCLUSION: We found that this method correctly identified different Juniperus species present in mixed air samples in the southcentral United States, an accomplishment that cannot be achieved using microscopic identification. We conclude that the qPCR method is more accurate and sensitive than current pollen monitoring techniques and, therefore, has the potential to be used in various pollen monitoring stations.

Late Miocene lineage divergence and ecological differentiation of rare endemic Juniperus blancoi: clues for the diversification of North American conifers.

Western North America and Mexico contain a large number of conifer species. This diversity could be the product of orographic and climate changes of the late Tertiary and Quaternary. In this study, we focus on the evolutionary history of Juniperus blancoi, in order to determine the impact of climate change and environmental heterogeneity on population differentiation. We estimated the population structure, phylogenetic relationships and historical demography of J. blancoi populations using nuclear genes. We correlated genetic structure with ecological differentiation, divergence times and changes in population size. Populations of J. blancoi are differentiated into three lineages that correspond to low-, mid- and high-altitude populations. The three groups diversified in the late Miocene, early Pliocene, with only a few events of gene flow since then. Two lineages in the north exhibited a pattern of population growth during the Pleistocene that could be linked to climate changes. Populations of J. blancoi experienced significant ecological differentiation and early divergence events, which correspond to periods of global cooling and mountain uplift during the Miocene. This suggests that mountain ranges in tropical and subtropical latitudes play an important role in the speciation and persistence of conifer taxa in diversity hotspots, by providing diverse environmental conditions.

Key innovations and niche variation promoted rapid diversification of the widespread Juniperus (Cupressaceae).

The processes of forming lineages undergoing widespread radiations remain a knowledge gap that is fundamental to our understanding of the geographic distributions of species. Although early studies emphasized the importance of dispersal ability and historical migration events, key innovations that promote rapid diversification and/or adaptation to new habitats may also strongly influence distribution ranges. Juniperus is the second largest genus of conifers and is widely distributed throughout the Northern Hemisphere. Here, we used phylogenetic, phenotypic, and climatic data to investigate the contributions of these processes to the wide distribution and rapid diversification of Juniperus. Combining a time-scaled phylogeny and macroevolutionary theory, we show that the key innovations of berry-like seed cones and dioecy promoted the rapid diversification of Juniperus and that increased dispersal ability promoted allopatric speciation. Ecological niches had significant divergence among different clades of Juniperus. Biogeographic results supported multiple long-distance dispersal events and niche variation that contributed to the modern range of Juniperus, while both phenotypic adaptation and ecological opportunity probably drove its distribution range. Our findings suggest that the current widespread distribution is likely the result of significant divergence driven by niche variation in which ecological opportunities from key innovation and phenotypic divergence.

Comparative analysis of chloroplast genomes of seven Juniperus species from Kazakhstan.

Juniperus species are shrubs or trees in the family Cupressaceae that play an important role in forest ecosystems. In this study, we report the complete sequences of the plastid (pt) genomes of five Juniperus species collected in Kazakhstan (J. communis, J. sibirica, J. pseudosabina, J. semiglobosa, and J. davurica). The sequences of the pt genomes of the five species were annotated in addition to two full pt genome sequences from J. sabina and J. seravschanica, which we have previously reported. The pt genome sequences of these seven species were compared to the pt genomes of Juniperus species available in the public NCBI database. The total length of the pt genomes of Juniperus species, including previously published pt genome data, ranged from 127,469 bp (J. semiglobosa) to 128,097 bp (J. communis). Each Juniperus plastome consisted of 119 genes, including 82 protein-coding genes, 33 transfer RNA and 4 ribosomal RNA genes. Among the identified genes, 16 contained one or two introns, and 2 tRNA genes were duplicated. A comparative assessment of pt genome sequences suggested the identification of 1145 simple sequence repeat markers. A phylogenetic tree of 26 Juniperus species based on the 82 protein-coding genes separated the Juniperus samples into two major clades, corresponding to the Juniperus and Sabina sections. The analysis of pt genome sequences indicated that accD and ycf2 were the two most polymorphic genes. The phylogenetic evaluation of 26 Juniperus species using these two genes confirmed that they can be efficiently used as DNA barcodes for phylogenetic analyses in the genus. The sequenced plastomes of these Juniperus species have provided a large amount of genetic data that will be valuable for future genomic studies of this genus.

What makes a good neighborhood? Interaction of spatial scale and fruit density in the predator satiation dynamics of a masting juniper tree.

Spatio-temporal variability in fruit production (masting) has been regarded as a key mechanism to increase plant fitness by reducing seed predation. However, considerably more effort has been devoted into understanding the consequences of temporal rather than spatial variations in fruit crop for plant fitness. In order to simultaneously evaluate both components, we quantify fruit production and pre-dispersal damage by three arthropod species (mites, chalcid wasps and moths) in the Spanish juniper (Juniperus thurifera) during 3 years in a spatially explicit context. Our aims were to assess (1) the interaction between fruit production and pre-dispersal fruit damage by arthropods, (2) the potential interference or competition between arthropods, and (3) the form of the phenotypic selection exerted by arthropods on fruit traits considering the spatial context. Arthropods damaged a substantial fraction of fruits produced by Spanish juniper with levels of damage showing sharp inter-annual variations. Fruit damage by mites was negatively related to yearly fruit crop and positively correlated at individual trees fruiting in consecutive years. Increased interspecific interference was an additional consequence of reduced fruit availability during small crop years. During a masting year, fruit damage by less mobile species such as mites was negatively affected by tree crop size, and no spatial structure was observed for mite damage. The incidence of chalcid wasps was low, so the spatial pattern of seed predation was unclear, and no preferences for fruit or seed traits were detected. Conversely, moths selected larger fruits and their incidence on trees was spatially aggregated up to 20 m, with predation levels being negatively affected by fruit abundance at the patch level, suggesting a positive density-dependent effect of neighbors on fruit output. These results highlight the importance of including the spatial component to understand complex species interactions at local scales.

[Genetic variability of juniper tall (Juniperus excelsa Bieb.) in the northern and southern limits of the natural distribution].

Genetic structure, subdivision and differentiation of six populations of juniper tall (Juniperus excelsa Bieb.) of the Crimean Mountains and of one population in Lebanon were investigated using 18 polymorphic allozyme loci as genetic markers. The high level of genetic variability of J. excelsa was established in the northern and the southern limits of its natural habitat. The mean values of the main indicators of genetic polymorphism were: P99 = 1,000, A = 3,167, H(E) = 0,370, H(o) = 0,405. Subdivision and differentiation of populations were low (F(ST) = 0,032, D(N) = 0,026) indicating similarity of their gene pools.

Diversity and bioactive potential of Actinomycetia from the rhizosphere soil of Juniperus excelsa.

Microbial natural products are among the main sources of compounds used in the medical biotechnology field for the purpose of drug development. However, as antibiotic resistance in pathogenic microorganisms is known to be increasing dramatically, there exists a need to develop new antibiotics. Actinomycetia have proven to be a good source of biologically active compounds, although the rediscovery of previously known compounds significantly slows down the introduction of new antibiotics. As a consequence, increasing attention is being paid to the isolation of actinomycete strains from previously unexplored sources, which can significantly increase the likelihood of discovering new biologically active compounds. This study investigated the diversity and bioactive potential of 372 actinomycete strains isolated from the rhizosphere soil of Juniperus excelsa M. Bieb. The examined actinomycete strains belonged to 11 genera, namely, Actinoplanes, Actinorectispora, Amycolatopsis, Kribbella, Micrococcus, Micromonospora, Nocardia, Promicromonospora, Rhodococcus, Saccharopolyspora and Streptomyces. The bioactive potential of each isolated actinomycete strain was determined on the basis of its ability to produce antimicrobial metabolites against Gram-positive and Gram-negative bacteria and yeast. Some 159 strains (42.74%) exhibited antimicrobial activity against at least one of the tested microbial strains. The dereplication analysis of the extract of the Streptomyces sp. Je 1-651 strain, which exhibited strong antimicrobial activity, led to the annotation of spiramycins and stambomycins. Moreover, the phylogenetic analysis based on the 16S rRNA gene sequence of the Je 1-651 strain revealed it to be close to the S. ambofaciens.

[Systematics and genegeography of Juniperus communis inferred from isoenzyme data].

Using isoenzyme analysis, 35 populations of Juniperus communis L. from various parts of the Russian species range and by one population from Sweden and Alaska were studied. The total sample size was 1200 plants. As a result, the existence ofJ. communis var. oblonga in North Caucasus and J. communis var. depressa in North America was confirmed, but genetic differences between J. communis var. communis and J. communis var. saxatilis were not detected in the main part of the Russian species range (European part of Russia, Ural, Siberia). These populations proved to be genetically uniform with the same predominant allelic frequencies, which may evidence recent settling of this species from one of Central or East European refugium. J. communis var. saxatilis from northeastern Russia inhabiting the region behind Verkhoyansk mountain and Russian Far East showed considerable differentiation in frequencies of alleles at three loci and geographical subdivision. These populations also exhibit high intrapopulation variation. This can be connected with the refugium in this territory. The origin of this group is probably connected with migrations from Central Asia (Tibet) in the direction to northeastern Russia along mountains connecting Central and North Asia. It is also assumed that migrations of this species previously proceeded across the Beringian land bridge.

Incipient speciation, high genetic diversity, and ecological divergence in the alligator bark juniper suggest complex demographic changes during the Pleistocene.

The most recent glacial cycles of the Pleistocene affected the distribution, population sizes, and levels of genetic structure of temperate-forest species in the main Mexican mountain systems. Our objective was to investigate the effects these cycles had on the genetic structure and distribution of a dominant species of the "mexical" vegetation across North and Central America. We studied the genetic diversity of Juniperus deppeana, a conifer distributed from the Southwestern United States to the highlands of Central America. We combined information of one plastid marker and two nuclear markers to infer phylogeographic structure, genetic diversity and demographic changes. We also characterized the climatic niche for each variety to infer the plausible area of suitability during past climatic conditions and to evaluate climatic niche discontinuities along with the species distribution. We found a marked phylogeographic structure separating the populations North and South of the Isthmus of Tehuantepec, with populations to the South of this barrier forming a distinct genetic cluster corresponding to Juniperus deppeana var. gamboana. We also found signals of population expansion in the Northern genetic cluster. Ecological niche modeling results confirmed climatic niche differences and discontinuities among J. deppeana varieties and heterogeneous responses to climatic oscillations. Overall, J. deppeana's genetic diversity has been marked by distribution shifts, population growth and secondary contact the North, and in situ permanence in the South since the last interglacial to the present. High genetic variation suggests a wide and climatically diverse distribution during climatic oscillations. We detected the existence of two main genetic clusters, supporting previous proposals that Juniperus deppeana and Juniperus gamboana may be considered two separate species.

Comparative analyses of six complete chloroplast genomes from the genus Cupressus and Juniperus (Cupressaceae).

Cupressaceae is a conifer family distributed around the world. Cupressus and Juniperus are the main genera of the Cupressaceae family and have important medicinal value. This leads to confusion between Cupressus and Juniperus due to similar morphologies. Here, the complete cp genomes of two Cupressus (C. duclouxiana and C. funebri) and four Juniperus (J. chinensis, J. gaussenii J. pingii and J. procumbens) were sequenced. The results revealed that the length of the cp genomes ranged from 126,996 bp to 129,959 bp, with 119 genes comprising 82 protein-coding genes, 33 transfer RNAs and 4 ribosomal RNAs. All chloroplast genomes of Cupressus and Juniperus lost whole IR regions, which is consistent with gymnosperm cp genome studies. In addition, the number of SSRs per species ranged from 54 to 73 and was dominated by mononucleotide repeats. In the six cp genomes of Cupressus and Juniperus, five highly divergent regions, including accD, accD-rpl2, ycf1, ycf2 and rrn23-rrn4.5, can be used as DNA barcodes of interspecific relationships and potential genetic markers. We compared the gene selection pressures (C. chengiana as reference species), and 6 genes underwent positive selection, the majority of which were related to photosynthesis. Phylogenetic results showed that the monophyly of Cupressus and Juniperus supported most bootstrap support. Cupressus funebris and J. chinensis were resolved to be early diverging species within Cupressus and Juniperus, and the two genera were sister groups to each other. This research revealed a new understanding of the structural pluralism and phylogenetic relationships of Cupressaceae cp genomes. These results will facilitate comprehension of the complexity and diversity of conifer cp genomes.

Genetic structure and seed-mediated dispersal rates of an endangered shrub in a fragmented landscape: a case study for Juniperus communis in northwestern Europe.

BACKGROUND: Population extinction risk in a fragmented landscape is related to the differential ability of the species to spread its genes across the landscape. The impact of landscape fragmentation on plant population dynamics will therefore vary across different spatial scales. We quantified successful seed-mediated dispersal of the dioecious shrub Juniperus communis in a fragmented landscape across northwestern Europe by using amplified fragment length polymorphism (AFLP) markers. Furthermore we investigated the genetic diversity and structure on two spatial scales: across northwestern Europe and across Flanders (northern Belgium). We also studied whether seed viability and populations size were correlated with genetic diversity. RESULTS: Unexpectedly, estimated seed-mediated dispersal rates were quite high and ranged between 3% and 14%. No population differentiation and no spatial genetic structure were detected on the local, Flemish scale. A significant low to moderate genetic differentiation between populations was detected at the regional, northwest European scale (PhiPT = 0.10). In general, geographically nearby populations were also genetically related. High levels of within-population genetic diversity were detected but no correlation was found between any genetic diversity parameter and population size or seed viability. CONCLUSIONS: In northwestern Europe, landscape fragmentation has lead to a weak isolation-by-distance pattern but not to genetic impoverishment of common juniper. Substantial rates of successful migration by seed-mediated gene flow indicate a high dispersal ability which could enable Juniperus communis to naturally colonize suitable habitats. However, it is not clear whether the observed levels of migration will suffice to counterbalance the effects of genetic drift in small populations on the long run.

Genetic variability and differentiation among populations of the Azorean endemic gymnosperm Juniperus brevifolia: baseline information for a conservation and restoration perspective.

The Azorean endemic gymnosperm Juniperus brevifolia (Seub.) Antoine is a top priority species for conservation in Macaronesia, based on its ecological significance in natural plant communities. To evaluate genetic variability and differentiation among J. brevifolia populations from the Azorean archipelago, we studied 15 ISSR and 15 RAPD markers in 178 individuals from 18 populations. The average number of polymorphic bands per population was 65 for both ISSR and RAPD. The majority of genetic variability was found within populations and among populations within islands, and this partitioning of variability was confirmed by AMOVA. The large majority of population pairwise F(ST) values were above 0.3 and below 0.6. The degree of population genetic differentiation in J. brevifolia was relatively high compared with other species, including Juniperus spp. The genetic differentiation among populations suggests that provenance should be considered when formulating augmentation or reintroduction strategies.

Molecular characterization and RAPD analysis of Juniperus species from Iran.

The genus Juniperus L. (Cupressaceae), an aromatic evergreen plant, consists of up to 68 species around the world. We classified five species of Juniperus found in Iran using molecular markers to provide a means for molecular identification of Iranian species. Plants were collected (three samples of each species) from two different provinces of Iran (Golestan and East Azarbayejan). The DNA was extracted from the leaves using a Qiagen Dneasy Plant Mini Kit. Amplification was performed using 18 ten-mer RAPD primers. Genetic distances were estimated based on 187 RAPD bands to construct a dendrogram by means of unweighted pair group method of arithmetic means. It was found that J. communis and J. oblonga were differentiated from the other species. Genetic distance values ranged from 0.19 (J. communis and J. oblonga) to 0.68 (J. communis and J. excelsa). Juniperus foetidissima was found to be most similar to J. sabina. Juniperus excelsa subspecies excelsa and J. excelsa subspecies polycarpos formed a distinct group.