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International Journal of Systematic and... Jan 2020
PubMed: 32019663
DOI: 10.1099/ijsem.0.003940 -
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 -
Annals of Botany May 2014The interaction between forest fragmentation and predicted climate change may pose a serious threat to tree populations. In small and spatially isolated forest...
BACKGROUND AND AIMS
The interaction between forest fragmentation and predicted climate change may pose a serious threat to tree populations. In small and spatially isolated forest fragments, increased homozygosity may directly affect individual tree fitness through the expression of deleterious alleles. Climate change-induced drought stress may exacerbate these detrimental genetic consequences of forest fragmentation, as the fitness response to low levels of individual heterozygosity is generally thought to be stronger under environmental stress than under optimal conditions.
METHODS
To test this hypothesis, a greenhouse experiment was performed in which various transpiration and growth traits of 6-month-old seedlings of Quercus robur differing in multilocus heterozygosity (MLH) were recorded for 3 months under a well-watered and a drought stress treatment. Heterozygosity-fitness correlations (HFC) were examined by correlating the recorded traits of individual seedlings to their MLH and by studying their response to drought stress.
KEY RESULTS
Weak, but significant, effects of MLH on several fitness traits were obtained, which were stronger for transpiration variables than for the recorded growth traits. High atmospheric stress (measured as vapour pressure deficit) influenced the strength of the HFCs of the transpiration variables, whereas only a limited effect of the irrigation treatment on the HFCs was observed.
CONCLUSIONS
Under ongoing climate change, increased atmospheric stress in the future may strengthen the negative fitness responses of trees to low MLH. This indicates the necessity to maximize individual multilocus heterozygosity in forest tree breeding programmes.
Topics: Biomass; Droughts; Genes, Plant; Heterozygote; Microsatellite Repeats; Quercus
PubMed: 24638819
DOI: 10.1093/aob/mcu025 -
Mycorrhiza Mar 2010In this study, we present the detailed molecular investigation of the ectomycorrhizal (ECM) community of Quercus petraea and Quercus robur seedlings grown in bare-root...
In this study, we present the detailed molecular investigation of the ectomycorrhizal (ECM) community of Quercus petraea and Quercus robur seedlings grown in bare-root forest nurseries. In all tested oak samples, mycorrhizal colonization was nearly 100%. Morphological observation and molecular investigations (sequencing of fungal ITS rDNA) revealed a total of 23 mycorrhizal taxa. The most frequent and abundant fungal taxa were Hebeloma sacchariolens, Tuber sp., and Peziza sp.; from the detected fungal taxa, 20 were noted for Q. petraea and 23 for Q. robur. Depending on the nursery, the species richness of identified ECM fungal taxa for both oak species ranged from six to 11 taxa. The mean species richness for all nurseries was 5.36 and 5.82 taxa per Q. petraea and Q. robur sample, respectively. According to the analysis of similarity, ECM fungal communities were similar for Q. petraea and Q. robur (R = 0.019; p = 0.151). On the other hand, detected fungal communities were significantly different between nurseries (R = 0.927; p < 0.0001). Using the Spearman rank correlation, it was determined that the ectomycorrhizal diversity (in terms of richness, the Shannon diversity, evenness, and Simpson dominance indices) is significantly related to the soil parameters of each nursery. We conclude that individual nursery may be considered as separate ecological niches that strongly discriminate diversity of ECM fungi.
Topics: Biodiversity; DNA, Fungal; DNA, Ribosomal Spacer; Fungi; Molecular Sequence Data; Mycorrhizae; Quercus; Seedlings; Sequence Analysis, DNA
PubMed: 19756776
DOI: 10.1007/s00572-009-0278-6 -
The New Phytologist 2006Here, a conceptual model is presented for the development of Phytophthora disease in pedunculate oak. The model is presented using the causal loop diagram tool and gives... (Review)
Review
Here, a conceptual model is presented for the development of Phytophthora disease in pedunculate oak. The model is presented using the causal loop diagram tool and gives an overview of how various abiotic and biotic factors, such as soil moisture, nutrient availability and mycorrhizal colonization, may affect the reproduction and the infective capacity of soil-borne Phytophthora species, the susceptibility of the host and subsequent disease development. It is suggested that the link between the root damage caused by Phytophthora species and overall tree vitality is in the assimilation and allocation of carbon within the plants. The potential impact of environmental factors on these processes is discussed. The model is presented with reference to scenarios related to variation in soil moisture and nutrient availability. The need for species-specific validation of the model and the implications of the model are discussed.
Topics: Carbon; Magnesium; Models, Biological; Nitrogen; Phytophthora; Plant Diseases; Plant Roots; Potassium; Quercus; Rain; Soil; Trees; Water
PubMed: 16771982
DOI: 10.1111/j.1469-8137.2006.01743.x -
Monatsschrift Fur Ohrenheilkunde Und... 1951
Topics: Carcinoma; Humans; Larynx
PubMed: 14852875
DOI: No ID Found -
The Science of the Total Environment Dec 2017Even though pedunculate oak (Quercus robur L.) and grayish oak (Quercus pedunculiflora K. Koch) have different ecological requirements, they have been considered as...
Leaf morphological variability and intraspecific taxonomic units for pedunculate oak and grayish oak (genus Quercus L., series Pedunculatae Schwz.) in Southern Carpathian Region (Romania).
Even though pedunculate oak (Quercus robur L.) and grayish oak (Quercus pedunculiflora K. Koch) have different ecological requirements, they have been considered as having low differentiation at the level of morphological traits and genetic variation. The leaf morphology for 862 trees has been assessed in 16 natural populations, seven of Q. robur, eight of Q. pedunculiflora and a mixed forest were both taxa coexist. In total, fifteen descriptors have been analysed by using discriminant analysis, while it was found that with only four out of the fifteen leaf traits (abaxial pubescence, abaxial colour of the leaf, petiole length and basal shape of lamina) the two taxa could be clearly differentiated. A dendrogram has been constructed on the basis of these traits, where the populations of each taxon have been clustered together. PU and CL traits of Q. pedunculiflora were discussed for their adaptive value for drought resistance in the steppe habitats occupied by this taxon. Using the leaves' morphological descriptors and data from the literature, intra-taxonomic units (varieties, forms and sub-forms) have been identified in all analysed populations. Eight intraspecific units for Q. robur and six for Q. pedunculiflora have been identified in the investigated area. An analysis of spatial distribution of the two taxa and of their intraspecific units has been performed using maps of ecoregions for the study area.
Topics: Genetic Variation; Genetics, Population; Plant Leaves; Quercus; Romania; Trees
PubMed: 28755599
DOI: 10.1016/j.scitotenv.2017.05.274 -
Plant, Cell & Environment Dec 2012The indirect defences of plants are comprised of herbivore-induced plant volatiles (HIPVs) that among other things attract the natural enemies of insects. However, the...
The indirect defences of plants are comprised of herbivore-induced plant volatiles (HIPVs) that among other things attract the natural enemies of insects. However, the actual extent of the benefits of HIPV emissions in complex co-evolved plant-herbivore systems is only poorly understood. The observation that a few Quercus robur L. trees constantly tolerated (T-oaks) infestation by a major pest of oaks (Tortrix viridana L.), compared with heavily defoliated trees (susceptible: S-oaks), lead us to a combined biochemical and behavioural study. We used these evidently different phenotypes to analyse whether the resistance of T-oaks to the herbivore was dependent on the amount and scent of HIPVs and/or differences in non-volatile polyphenolic leaf constituents (as quercetin-, kaempferol- and flavonol glycosides). In addition to non-volatile metabolic differences, typically defensive HIPV emissions differed between S-oaks and T-oaks. Female moths were attracted by the blend of HIPVs from S-oaks, showing significantly higher amounts of (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) and (E)-β-ocimene and avoid T-oaks with relative high fraction of the sesquiterpenes α-farnesene and germacrene D. Hence, the strategy of T-oaks exhibiting directly herbivore-repellent HIPV emissions instead of high emissions of predator-attracting HIPVs of the S-oaks appears to be the better mechanism for avoiding defoliation.
Topics: Animals; Chromatography, Gas; Feeding Behavior; Female; Mass Spectrometry; Moths; Quercus; Volatile Organic Compounds
PubMed: 22632165
DOI: 10.1111/j.1365-3040.2012.02545.x -
The Science of the Total Environment Dec 2019This study focuses on the climate growth drivers of Quercus robur L. (pedunculate oak) and Q. robur subsp. pedunculiflora K. Koch. (greyish oak), occurring in the...
This study focuses on the climate growth drivers of Quercus robur L. (pedunculate oak) and Q. robur subsp. pedunculiflora K. Koch. (greyish oak), occurring in the biodiversity of three sites in southern Romania. We determined the degree of tolerance of the greyish oak, between the tardive and praecox varieties, to environmental stress, between 1951 and 2016. Total tree ring-width (RW), and earlywood (EW) and latewood (LW) measurements were subject of periodical and monthly climate-growth analysis. Our results revealed a moderate relationship between climate and tree-growth. A significant and positive relationship was observed between RW and previous growing season precipitation. Mean and minimum temperatures affected both positive and negative tree-rings during the growing season. We also observed that winter and spring represent key seasons for differentiating tardive from praecox varieties, affecting the intra-annual variability of ring-width, and EW and LW parameters. The correlation between the tree-ring measurements and daily climate data shows a clear offset of the starting growth between greyish oak varieties. A weak influence of stressors on tree-growth at the sites was observed through pointer year and resilience components analysis.
Topics: Climate; Environmental Monitoring; Quercus; Romania
PubMed: 31394332
DOI: 10.1016/j.scitotenv.2019.133709 -
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