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Molecular Ecology Jul 2016Low-latitudinal range margins of temperate and boreal plant species typically consist of scattered populations that persist locally in microrefugia. It remains poorly...
Low-latitudinal range margins of temperate and boreal plant species typically consist of scattered populations that persist locally in microrefugia. It remains poorly understood how their refugial habitats affect patterns of gene flow and connectivity, key components for their long-term viability and evolution. We examine landscape-scale patterns of historical and contemporary gene flow in refugial populations of the widespread European forest tree Pedunculate oak (Quercus robur) at the species' southwestern range margin. We sampled all adult trees (n = 135) growing in a 20 km long valley and genotyped 724 acorns from 72 mother trees at 17 microsatellite loci. The ten oak stands that we identified were highly differentiated and formed four distinct genetic clusters, despite sporadic historical dispersal being detectable. By far most contemporary pollination occurred within stands, either between local mates (85.6%) or through selfing (6.8%). Pollen exchange between stands (2.6%) was remarkably rare given their relative proximity and was complemented by long-distance pollen immigration (4.4%) and hybridization with the locally abundant Quercus pyrenaica (0.6%). The frequency of between-stand mating events decreased with increasing size and spatial isolation of stands. Overall, our results reveal outstandingly little long-distance gene flow for a wind-pollinated tree species. We argue that the distinct landscape characteristics of oaks' refugial habitats, with a combination of a rugged topography, dense vegetation and humid microclimate, are likely to increase plant survival but to hamper effective long-distance pollen dispersal. Moreover, local mating might be favoured by high tree compatibility resulting from genetic purging in these long-term relict populations.
Topics: Ecosystem; Gene Flow; Genetics, Population; Genotype; Hybridization, Genetic; Microsatellite Repeats; Models, Genetic; Pollen; Pollination; Quercus; Refugium; Spain; Trees
PubMed: 27146553
DOI: 10.1111/mec.13692 -
Natural Product Research 2023We tested anti-herpetic effect of castalagin, an ellagitannin compound, extracted from pedunculate oak (). Previous investigations found that castalagin possesses a...
We tested anti-herpetic effect of castalagin, an ellagitannin compound, extracted from pedunculate oak (). Previous investigations found that castalagin possesses a strong inhibitory effect against HSV-1/2 equal to acyclovir (ACV). It is also effective against ACV-resistant mutants and shows a synergistic effect with ACV. We study castalagin's activity towards HSV-1 infection in newborn mice. Acute toxicity determination in mice showed LD value of 295 mg/kg. Prolonged toxicity was also constructed. Castalagin manifested a marked activity against HSV-1 (LD/0.02 ml) administered in 7-day course at 0.02 ml s.c. doses of 7.5 or 10 mg/kg (PI 57-58%). ACV course demonstrated a marked activity at 20 mg/kg. The selectivity ratio LD/ED (295/7.5) could be accepted as ≥ 33.
Topics: Mice; Animals; Herpesvirus 1, Human; Hydrolyzable Tannins; Antiviral Agents; Animals, Newborn; Herpes Simplex; Acyclovir; Herpesvirus 2, Human
PubMed: 36714926
DOI: 10.1080/14786419.2023.2173191 -
Journal of Economic Entomology Oct 2021Oak lace bug - Corythucha arcuata (Say, 1832) (Hemiptera: Tingidae) is a North American species that has been introduced to Europe and Asia, where it became a serious...
Oak lace bug - Corythucha arcuata (Say, 1832) (Hemiptera: Tingidae) is a North American species that has been introduced to Europe and Asia, where it became a serious oak pest. As little is known about its behavior, we conducted a study in which we tested the preference and performance of the oak lace bug for different oak species and the influence of powdery mildew and CO2 on the behavior of the oak lace bug. Four of the most represented oak species in Serbia (Hungarian, pedunculate, sessile, and Turkey oak) were used for testing the preference and performance of the oak lace bug, and the influence of oak powdery mildew on the behavior of the oak lace bug. The influence of CO2 on the behavior of the oak lace bug was tested on pedunculate oak. The results of this study have shown that there are differences in preference and performance of the oak lace bug between the analyzed oak species; there are significant differences in the oak lace bug host preference in the laboratory and in field conditions; Hungarian oak is most threatened by the oak lace bug, as the oak lace bug performs best on this species and preferers this species in field conditions; the oak powdery mildew and oak lace bug are in an antagonistic relationship; and that the changes in the leaves caused by the expected increase in CO2 concentration in the future will probably not influence the feeding behavior of the oak lace bug adults.
Topics: Animals; Asia; Europe; Feeding Behavior; Heteroptera; Quercus
PubMed: 34343281
DOI: 10.1093/jee/toab148 -
Plants (Basel, Switzerland) Jun 2023The conservation of the genetic resources of old trees is crucial to their ecological role but is extremely difficult, especially for oak species ( spp.) displaying...
The conservation of the genetic resources of old trees is crucial to their ecological role but is extremely difficult, especially for oak species ( spp.) displaying recalcitrance in seed and vegetative propagation methods. Our study aimed to assess the regenerative potential of trees of different ages (up to 800 years) during micropropagation. We also aimed to determine how in vitro conditions can influence in vitro regeneration responses. Lignified branches collected from 67 selected trees were cultivated ex vitro in culture pots at 25 °C to obtain epicormic shoots (explant sources). The explants were cultivated on an agar medium supplemented with 0.8 mg L 6-benzylaminopurine (BAP) for at least 21 months. In a second experiment, two different shoot multiplication conditions (temporary immersion-RITA bioreactor and agar medium) and two culture medium formulations (Woody Plant Medium and modified Quoirin and Lepoivre medium) were tested. The results showed that the mean length of the epicormic shoots obtained in a pot culture was a function of donor age and was similar among the group of younger trees (ca. 20-200 years), and varied between older trees (ca. 300-800 years). The efficiency of in vitro shoot multiplication strictly depended on the genotype. A sustainable in vitro culture (defined as survival after 6 months) was only possible for half of the tested old donor trees, even when they survived the first month of in vitro growth. A continuous monthly increase in the number of in vitro cultured shoots was reported in younger oaks and in some old oaks. We found a significant effect of the culture system and the macro- and micronutrient composition on in vitro shoot growth. This is the first report demonstrating that the in vitro culture can be successfully applied to the propagation of even 800-year-old pedunculate oak trees.
PubMed: 37375856
DOI: 10.3390/plants12122230 -
American Journal of Botany May 2024During the last centuries, the area covered by urban landscapes is increasing all over the world. Urbanization can change local habitats and decrease connectivity among...
PREMISE
During the last centuries, the area covered by urban landscapes is increasing all over the world. Urbanization can change local habitats and decrease connectivity among these habitats, with important consequences for species interactions. While several studies have found a major imprint of urbanization on plant-insect interactions, the effects of urbanization on seed predation remain largely unexplored.
METHODS
We investigated the relative impact of sunlight exposure, leaf litter, and spatial connectivity on predation by moth and weevil larvae on acorns of the pedunculate oak across an urban landscape during 2018 and 2020. We also examined whether infestations by moths and weevils were independent of each other.
RESULTS
While seed predation varied strongly among trees, seed predation was not related to differences in sunlight exposure, leaf litter, or spatial connectivity. Seed predation by moths and weevils was negatively correlated at the level of individual acorns in 2018, but positively correlated at the acorn and the tree level in 2020.
CONCLUSIONS
Our study sets the baseline expectation that urban seed predators are unaffected by differences in sunlight exposure, leaf litter, and spatial connectivity. Overall, our findings suggest that the impact of local and spatial factors on insects within an urban context may depend on the species guild. Understanding the impact of local and spatial factors on biodiversity, food web structure, and ecosystem functioning can provide valuable insights for urban planning and management strategies aimed at promoting urban insect diversity.
Topics: Animals; Seeds; Moths; Ecosystem; Weevils; Quercus; Larva; Urbanization; Cities; Sunlight; Food Chain
PubMed: 38757608
DOI: 10.1002/ajb2.16333 -
ZooKeys 2022This study provides the first data on the genital anatomy, jaw and radula of (L. Pfeiffer, 1863). The auxiliary copulatory organ of this species is very peculiar,...
This study provides the first data on the genital anatomy, jaw and radula of (L. Pfeiffer, 1863). The auxiliary copulatory organ of this species is very peculiar, similar to that of L. Pfeiffer, 1877, and different from that of other cepolids. It consists of an elongate, pedunculate mucus gland inserted apically on a muscular papilla and an atrial sac, all covered by a sheath. A sheath-like accessory gland is inserted at the base of the atrial sac. Another similarity with is the presence of a fertilization pouch-spermatheca complex with a single exposed spermatheca. Like , has an oxygnath, highly arched jaw with slight striae over the entire surface and a broad, well-developed median projection. The radula has triangular and monocuspid central and lateral teeth (the central teeth are smaller than the rest). The marginal teeth are multicuspid with the mesocone and ectocones smaller than the endocones. The similar structures of the auxiliary copulatory organ (without dart sac) and spermatheca (simple) strongly suggest that and spp. are closely related. As such, it remains to be decided whether Clench & Aguayo, 1951 and should continue to be treated as separate genera.
PubMed: 35068965
DOI: 10.3897/zookeys.1080.73194 -
International Journal of Systematic and... Nov 2019Twenty-two cream-coloured bacterial strains were isolated from oak trees affected by acute oak decline (AOD) in Southern England. Isolates were Gram-negative, motile,...
Twenty-two cream-coloured bacterial strains were isolated from oak trees affected by acute oak decline (AOD) in Southern England. Isolates were Gram-negative, motile, slightly curved rods, aerobic, non-spore-forming, catalase positive and oxidase positive. 16S rRNA gene sequence analysis placed the strains in two separate phylogenetic clusters in the group, with as the closest phylogenetic relative. Multilocus sequence analyses of the , and genes supported the delineation of the strains into two separate taxa, which could be differentiated phenotypically and chemotaxonomically from each other, and their closest relatives. Average nucleotide identity and DNA-DNA hybridization values revealed percentages of genome similarity below the species threshold (95 and 70 %, respectively) between the two taxa and the closest relatives, confirming their novel species status. Therefore, on the basis of this polyphasic approach we propose two novel species, sp. nov. (type strain FRB 228=LMG 31087=NCPPB 4672) and sp. nov. (type strain FRB 230=LMG 31087=NCPPB 4673).
Topics: Bacterial Typing Techniques; Base Composition; DNA, Bacterial; Fatty Acids; Genes, Bacterial; Multilocus Sequence Typing; Nucleic Acid Hybridization; Phylogeny; Plant Diseases; Pseudomonas; Quercus; RNA, Ribosomal, 16S; Sequence Analysis, DNA; United Kingdom
PubMed: 31391144
DOI: 10.1099/ijsem.0.003615 -
Ecology and Evolution May 2017The diversity of plant neighbors commonly results in direct, bottom-up effects on herbivore ability to locate their host, and in indirect effects on herbivores involving...
The diversity of plant neighbors commonly results in direct, bottom-up effects on herbivore ability to locate their host, and in indirect effects on herbivores involving changes in plant traits and a top-down control by their enemies. Yet, the relative contribution of bottom-up and top-down forces remains poorly understood. We also lack knowledge on the effect of abiotic constraints such as summer drought on the strength and direction of these effects. We measured leaf damage on pedunculate oak (), alone or associated with birch, pine or both in a long-term tree diversity experiment (ORPHEE), where half of the plots were irrigated while the other half remained without irrigation and received only rainfall. We tested three mechanisms likely to explain the effects of oak neighbors on herbivory: (1) Direct bottom-up effects of heterospecific neighbors on oak accessibility to herbivores, (2) indirect bottom-up effects of neighbors on the expression of leaf traits, and (3) top-down control of herbivores by predators. Insect herbivory increased during the growth season but was independent of neighbor identity and irrigation. Specific leaf area, leaf toughness, and thickness varied with neighbor identity while leaf dry matter content or C:N ratio did not. When summarized in a principal component analysis (PCA), neighbor identity explained 87% of variability in leaf traits. PCA axes partially predicted herbivory. Despite greater rates of attack on dummy caterpillars in irrigated plots, avian predation, and insect herbivory remained unrelated. Our study suggests that neighbor identity can indirectly influence insect herbivory in mixed forests by modifying leaf traits. However, we found only partial evidence for these trait-mediated effects and suggest that more attention should be paid to some unmeasured plant traits such as secondary metabolites, including volatile organic compounds, to better anticipate the effects of climate change on plant-insect interactions in the future.
PubMed: 28515887
DOI: 10.1002/ece3.2950 -
Tree Physiology Nov 2016Waterlogging causes stressful conditions for perennial species. The temporary overabundance of water in waterlogged soil can induce hypoxia in the rhizosphere, leading...
Waterlogging causes stressful conditions for perennial species. The temporary overabundance of water in waterlogged soil can induce hypoxia in the rhizosphere, leading to root death, tree decline and even dieback. Two closely related members of the European white oak complex, pedunculate (Quercus robur L.) and sessile (Quercus petraea Matt. Liebl.) oaks, have different ecological characteristics, especially regarding their adaptation to soil waterlogging. The tolerance of waterlogging observed in pedunculate oak is driven principally by its ability to produce adaptive structures, hypertrophied lenticels and adventitious roots, and to switch rapidly its metabolism to the fermentative pathway. This study had two objectives: (i) to identify genes important for adaptation to waterlogging and (ii) to gain insight into the molecular mechanisms involved in hypertrophied lenticel formation in pedunculate oak. We subjected seedlings of the two species to hypoxia by maintaining the water level 2 cm above the collar. The immersed part of the stem (i.e., containing hypertrophied lenticels in pedunculate oak) was sampled after 9 days of waterlogging stress and its gene expression was investigated by RNA-seq. Genes displaying differential expression between the two species were identified with the DESeq R package and a false discovery rate of 0.001. We found that 3705 contigs were differentially regulated between the two species. Twenty-two differentially expressed genes were validated by real-time quantitative polymerase chain reaction. The suberin biosynthesis pathway was found to be upregulated in pedunculate oak, consistent with molecular mechanisms analogous to those operating in the radial oxygen loss barrier in waterlogging-tolerant species.
Topics: Adaptation, Physiological; Fermentation; Genes, Plant; Lipids; Plant Roots; Plant Stems; Quercus; Species Specificity; Trees; Water
PubMed: 27358207
DOI: 10.1093/treephys/tpw056 -
Communications Biology May 2021Transmembrane conductance of small uncharged solutes such as glycerol typically occurs through aquaglyceroporins (Glps), which are commonly encoded by multiple genes in...
Transmembrane conductance of small uncharged solutes such as glycerol typically occurs through aquaglyceroporins (Glps), which are commonly encoded by multiple genes in metazoan organisms. To date, however, little is known concerning the evolution of Glps in Crustacea or what forces might underly such apparent gene redundancy. Here, we show that Glp evolution in Crustacea is highly divergent, ranging from single copy genes in species of pedunculate barnacles, tadpole shrimps, isopods, amphipods and decapods to up to 10 copies in diplostracan water fleas although with monophyletic origins in each lineage. By contrast the evolution of Glps in Copepoda appears to be polyphyletic, with surprisingly high rates of gene duplication occurring in a genera- and species-specific manner. Based upon functional experiments on the Glps from a parasitic copepod (Lepeophtheirus salmonis), we show that such lineage-level gene duplication and splice variation is coupled with a high rate of neofunctionalization. In the case of L. salmonis, splice variation of a given gene resulted in tissue- or sex-specific expression of the channels, with each variant evolving unique sites for protein kinase C (PKC)- or protein kinase A (PKA)-regulation of intracellular membrane trafficking. The combined data sets thus reveal that mutations favouring a high fidelity control of intracellular trafficking regulation can be a selection force for the evolution and retention of multiple Glps in copepods.
Topics: Animals; Aquaglyceroporins; Biological Evolution; Copepoda; Crustacea; Evolution, Molecular; Genetic Variation; Multigene Family; Phylogeny; Protein Isoforms
PubMed: 34059783
DOI: 10.1038/s42003-021-01921-9