| 1. |
- Capador‐Barreto, Hernán D., et al.
(author)
-
Killing two enemies with one stone? : Genomics of resistance to two sympatric pathogens in Norway spruce
- 2021
-
In: Molecular Ecology. - : John Wiley & Sons. - 0962-1083 .- 1365-294X. ; 30:18, s. 4433-4447
-
Journal article (peer-reviewed)abstract
- Trees must cope with the attack of multiple pathogens, often simultaneously during their long lifespan. Ironically, the genetic and molecular mechanisms controlling this process are poorly understood. The objective of this study was to compare the genetic component of resistance in Norway spruce to Heterobasidion annosum s.s. and its sympatric congener Heterobasidion parviporum. Heterobasidion root- and stem-rot is a major disease of Norway spruce caused by members of the Heterobasidion annosum species complex. Resistance to both pathogens was measured using artificial inoculations in half-sib families of Norway spruce trees originating from central to northern Europe. The genetic component of resistance was analysed using 63,760 genome-wide exome-capture sequenced SNPs and multitrait genome-wide associations. No correlation was found for resistance to the two pathogens; however, associations were found between genomic variants and resistance traits with synergic or antagonist pleiotropic effects to both pathogens. Additionally, a latitudinal cline in resistance in the bark to H. annosum s.s. was found; trees from southern latitudes, with a later bud-set and thicker stem diameter, allowed longer lesions, but this was not the case for H. parviporum. In summary, this study detects genomic variants with pleiotropic effects which explain multiple disease resistance from a genic level and could be useful for selection of resistant trees to both pathogens. Furthermore, it highlights the need for additional research to understand the evolution of resistance traits to multiple pathogens in trees.
|
|
| 2. |
- Chen, Zhi‑Qiang, et al.
(author)
-
Early selection for resistance to Heterobasidion parviporum in Norway spruce is not likely to adversely affect growth and wood quality traits in late-age performance
- 2018
-
In: European Journal of Forest Research. - : Springer Science and Business Media LLC. - 1612-4669 .- 1612-4677. ; 137:4, s. 517-525
-
Journal article (peer-reviewed)abstract
- Infections with Heterobasidion parviporum devalue the Norway spruce timber as the decayed wood does not meet the necessary quality requirements for sawing. To evaluate the incorporation of disease resistance in the Norway spruce breeding strategy, an inoculation experiment with H. parviporum on 2-year-old progenies of 466 open-pollinated families was conducted under greenhouse (nursery) conditions. Lesion length in the phloem (LL), fungal growth in sapwood (FG) and growth (D) were measured on an average of 10 seedlings for each family. The genetic variation and genetic correlations between both LL, FG and growth in the nursery trial and wood quality traits measured previously from 21-year old trees in two progeny trials, including solid-wood quality traits (wood density, and modulus of elasticity) and fiber properties traits (radial fiber width, tangential fiber width, fiber wall thickness, fiber coarseness, microfibril angle and fiber length). For both LL and FG, large coefficients of phenotypic variation (> 26%) and genetic variation (> 46%) were detected. Heritabilities of LL and FG were 0.33 and 0.42, respectively. We found no significant correlations between wood quality traits and growth in the field progeny trials with neither LL nor FG in the nursery trial. Our data suggest that the genetic gains may reach 41 and 52% from mass selection by LL and FG, respectively. Early selection for resistance to H. parviporum based on assessments of fungal spread in the sapwood in nursery material, FG, will not adversely affect growth and wood quality traits in late-age performance.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Terenius, Olle, et al.
(author)
-
RNA interference in Lepidoptera : An overview of successful and unsuccessful studies and implications for experimental design
- 2011
-
In: Journal of insect physiology. - : Elsevier BV. - 0022-1910 .- 1879-1611. ; 57:2, s. 231-245
-
Journal article (peer-reviewed)abstract
- Gene silencing through RNA interference (RNAi) has revolutionized the study of gene function, particularly in non-model insects. However, in Lepidoptera (moths and butterflies) RNAi has many times proven to be difficult to achieve. Most of the negative results have been anecdotal and the positive experiments have not been collected in such a way that they are possible to analyze. In this review, we have collected detailed data from more than 150 experiments including all to date published and many unpublished experiments. Despite a large variation in the data, trends that are found are that RNAi is particularly successful in the family Saturniidae and in genes involved in immunity. On the contrary, gene expression in epidermal tissues seems to be most difficult to silence. In addition, gene silencing by feeding dsRNA requires high concentrations for success. Possible causes for the variability of success in RNAi experiments in Lepidoptera are discussed. The review also points to a need to further investigate the mechanism of RNAi in lepidopteran insects and its possible connection to the innate immune response. Our general understanding of RNAi in Lepidoptera will be further aided in the future as our public database at http://insectacentral.org/RNAi will continue to gather information on RNAi experiments.
|
|
| 7. |
- van Maurik, Ingrid S., et al.
(author)
-
Biomarker-based prognosis for people with mild cognitive impairment (ABIDE) : a modelling study
- 2019
-
In: Lancet Neurology. - : The Lancet Publishing Group. - 1474-4422 .- 1474-4465. ; 18:11, s. 1034-1044
-
Journal article (peer-reviewed)abstract
- BACKGROUND: Biomarker-based risk predictions of dementia in people with mild cognitive impairment are highly relevant for care planning and to select patients for treatment when disease-modifying drugs become available. We aimed to establish robust prediction models of disease progression in people at risk of dementia.METHODS: In this modelling study, we included people with mild cognitive impairment (MCI) from single-centre and multicentre cohorts in Europe and North America: the European Medical Information Framework for Alzheimer's Disease (EMIF-AD; n=883), Alzheimer's Disease Neuroimaging Initiative (ADNI; n=829), Amsterdam Dementia Cohort (ADC; n=666), and the Swedish BioFINDER study (n=233). Inclusion criteria were a baseline diagnosis of MCI, at least 6 months of follow-up, and availability of a baseline Mini-Mental State Examination (MMSE) and MRI or CSF biomarker assessment. The primary endpoint was clinical progression to any type of dementia. We evaluated performance of previously developed risk prediction models-a demographics model, a hippocampal volume model, and a CSF biomarkers model-by evaluating them across cohorts, incorporating different biomarker measurement methods, and determining prognostic performance with Harrell's C statistic. We then updated the models by re-estimating parameters with and without centre-specific effects and evaluated model calibration by comparing observed and expected survival. Finally, we constructed a model combining markers for amyloid deposition, tauopathy, and neurodegeneration (ATN), in accordance with the National Institute on Aging and Alzheimer's Association research framework.FINDINGS: We included all 2611 individuals with MCI in the four cohorts, 1007 (39%) of whom progressed to dementia. The validated demographics model (Harrell's C 0·62, 95% CI 0·59-0·65), validated hippocampal volume model (0·67, 0·62-0·72), and updated CSF biomarkers model (0·72, 0·68-0·74) had adequate prognostic performance across cohorts and were well calibrated. The newly constructed ATN model had the highest performance (0·74, 0·71-0·76).INTERPRETATION: We generated risk models that are robust across cohorts, which adds to their potential clinical applicability. The models could aid clinicians in the interpretation of CSF biomarker and hippocampal volume results in individuals with MCI, and help research and clinical settings to prepare for a future of precision medicine in Alzheimer's disease. Future research should focus on the clinical utility of the models, particularly if their use affects participants' understanding, emotional wellbeing, and behaviour.
|
|
| 8. |
- Vos, Joris, et al.
(author)
-
Looking into the cradle of the grave: J22564-5910, a potential young post-merger hot subdwarf
- 2021
-
In: Astronomy & Astrophysics. - : EDP Sciences. - 1432-0746 .- 0004-6361. ; 655
-
Journal article (peer-reviewed)abstract
- Context. We present the discovery of J22564-5910, a new type of hot subdwarf (sdB) which shows evidence of gas present in thesystem and it has shallow, multi-peaked hydrogen and helium lines which vary in shape over time. All observational evidence pointstowards J22564-5910 being observed very shortly after the merger phase that formed it.Aims. Using high-resolution, high signal-to-noise spectroscopy, combined with multi-band photometry, Gaia astrometry, and TESSlight curves, we aim to interpret these unusual spectral features.Methods. The photometry, spectra, and light curves were all analysed, and their results were combined in order to support ourinterpretation of the observations: the likely presence of a magnetic field combined with gas features around the sdB. Based onthe triple-peaked H lines, the magnetic field strength was estimated and, by using the shellspec code, qualitative models of gasconfigurations were fitted to the observations.Results. All observations can either be explained by a magnetic field of ∼650 kG, which enables the formation of a centrifugalmagnetosphere, or a non-magnetic hot subdwarf surrounded by a circumstellar gas disc or torus. Both scenarios are not mutuallyexclusive and both can be explained by a recent merger.Conclusions. J22564-5910 is the first object of its kind. It is a rapidly spinning sdB with gas still present in the system. It is thefirst post-merger star observed this early after the merger event, and as such it is very valuable system to test merger theories. If themagnetic field can be confirmed, it is not only the first magnetic sdB, but it hosts the strongest magnetic field ever found in a pre-whitedwarf object. Thus, it could represent the long sought-after immediate ancestor of strongly magnetic white dwarfs.
|
|
