Papers by Ulla Carlsson-Granér
Dryad ID14-0403R1
Data from inoculation experiment
Plant Disease
University of California Press eBooks, Dec 31, 2019
bioRxiv (Cold Spring Harbor Laboratory), Jun 25, 2022
Our knowledge of aquatic fungal communities, their assembly, distributions and ecological roles i... more Our knowledge of aquatic fungal communities, their assembly, distributions and ecological roles in marine ecosystems is scarce. Hence, we aimed to investigate fungal metacommunities of coastal habitats in a subarctic zone (northern Baltic Sea, Sweden). Using a novel joint species distribution model and network approach, we quantified the importance of biotic associations contributing to the assembly of mycoplankton, further, detected potential biotic interactions between fungi-algae pairs, respectively. Our long-read metabarcoding approach identified 504 fungal taxa, of which a dominant fraction (44.8 %) was assigned as early-diverging fungi (i.e., Cryptomycota and Chytridiomycota). Alpha diversity of mycoplankton declined and community compositions changed along inlet-bayoffshore transects. The distributions of most fungi were rather influenced by spatial factors than by environmental drivers, and the influence of biotic associations was pronounced when environmental filtering was weak and spatial patterning lessened. We found great number of co-occurrences (138) among the dominant fungal groups, and the forty associations between fungal and algal OTUs suggested potential host-parasite/saprotroph links, supporting a Cryptomycota-based mycoloop pathway. We emphasize that the contribution of biotic associations to mycoplankton assembly are important to consider in future studies as it helps to improve predictions of species distributions in aquatic ecosystems.
Evolutionary Ecology Research, 2006
Questions: How do disease transmission rates, host longevity, and spatial structure interact to d... more Questions: How do disease transmission rates, host longevity, and spatial structure interact to determine disease dynamics and evolution of host resistance in systems where host sterility is the major consequence of infection? Features of model: A spatially explicit two-dimensional simulation model with deterministic within-population birth and death processes, but stochastic among-population dispersal. The model assumes frequency-dependent disease transmission, and is loosely based on the pollinator-transmitted anther-smut fungus Microbotryum violaceum, which infects and sterilizes host plants in the Caryophyllaceae. Resistance varies among host individuals and is associated with a fitness cost. Ranges of key variables: Simulations were run over ranges of host death rates, disease transmission rates, and spatial structures observed in natural host species. Conclusions: The simulation model predicts that: (i) increasing host longevity and connectivity of host patches is likely to select for pathogen strains with lower transmission rates; (ii) when hosts are short-lived or populations are isolated, susceptible genotypes with higher reproductive output may have a selective advantage even when disease is widespread; (iii) when hosts are longer-lived or populations are more connected, resistance costs are lower and resistance can evolve to higher levels. Existing data from natural host-pathogen systems support these conclusions, although predictions about resistance patterns need to be tested in future studies.
Evolutionary Ecology Research, May 15, 2005
Hypothesis: In host-pathogen metapopulations, founder events and restricted gene flow cause diffe... more Hypothesis: In host-pathogen metapopulations, founder events and restricted gene flow cause differentiation in susceptibility among patches and populations of the host. Patterns of disease spread correspond to levels of susceptibility in host populations. Organism: The host-plant Silene dioica and the sterilizing anther-smut fungus Microbotryum violaceum. Study site: An archipelago in northern Sweden where populations of S. dioica constitute a hierarchically age-structured metapopulation and where M. violaceum is common. Methods: Plants from patches within recently diseased island populations were transplanted into an experimental population where they were naturally exposed to the anther-smut. We also included two populations with a long history of disease. Results: We found that susceptibility varied among recently diseased populations, while no significant differentiation in susceptibility was detected among patches within populations. Populations showing an increase in disease prevalence in the in-situ populations were more susceptible in the experiment than populations where the disease has remained at low levels. The more susceptible populations showed similar levels of susceptibility to the populations with a long history of disease. Conclusion: We propose that the combination of restricted host and pathogen dispersal and high turnover rates of host patches within populations maintain variation for resistance and mediate host-pathogen coexistence at the metapopulation level.
Floral sex ratios, disease and seed set in dioecious Silene dioica
Journal of Ecology, 1998
ABSTRACT
Alpine Botany, 2017
Despite the strong environmental control of seed dormancy and longevity, their changes along lati... more Despite the strong environmental control of seed dormancy and longevity, their changes along latitudes are poorly understood. The aim of this study was to assess seed dormancy and longevity in different populations across the distribution of the arctic-alpine plant Silene suecica. Seeds of seven populations collected from alpine (Spain, Italy, Scotland) and subarctic (Sweden, Norway) populations were incubated at four temperature regimes and five cold stratification intervals for germination and dormancy testing. Seed longevity was studied by exposing seeds to controlled ageing (45°C, 60% RH) and regularly sampled for germination. Fresh seeds of S. suecica germinated at warm temperature (20/15°C) and more in subarctic (80-100%) compared to alpine (20-50%) populations showed a negative correlation with autumn temperature (i.e., post-dispersal period). Seed germination increased after cold stratification in all populations, with different percentages (30-100%). Similarly, there was a large variation of seed longevity (p 50 = 12-32 days), with seeds from the wettest locations showing faster deterioration rate. Subarctic populations of S. suecica were less dormant, showing a warmer suitable temperature range for germination, and a higher germinability than alpine populations. Germination and dormancy were driven by an interplay of geographical and climatic factors, with alpine and warm versus subarctic and cool autumn conditions, eliciting a decrease and an increase of emergence, respectively. Germination and dormancy patterns typically found in alpine habitats may not be found in the arctic. Keywords Seed dormancy and germination Á Central and marginal population Á Climate change Á Reproduction Á Alpine species Á Adaptation
Evolutionary Ecology Research, Mar 1, 2005
Hypothesis: In host-pathogen metapopulations, founder events and restricted gene flow cause diffe... more Hypothesis: In host-pathogen metapopulations, founder events and restricted gene flow cause differentiation in susceptibility among patches and populations of the host. Patterns of disease spread correspond to levels of susceptibility in host populations. Organism: The host-plant Silene dioica and the sterilizing anther-smut fungus Microbotryum violaceum. Study site: An archipelago in northern Sweden where populations of S. dioica constitute a hierarchically age-structured metapopulation and where M. violaceum is common. Methods: Plants from patches within recently diseased island populations were transplanted into an experimental population where they were naturally exposed to the anther-smut. We also included two populations with a long history of disease. Results: We found that susceptibility varied among recently diseased populations, while no significant differentiation in susceptibility was detected among patches within populations. Populations showing an increase in disease prevalence in the in-situ populations were more susceptible in the experiment than populations where the disease has remained at low levels. The more susceptible populations showed similar levels of susceptibility to the populations with a long history of disease. Conclusion: We propose that the combination of restricted host and pathogen dispersal and high turnover rates of host patches within populations maintain variation for resistance and mediate host-pathogen coexistence at the metapopulation level.
Evolution; international journal of organic evolution, Jan 3, 2015
Theory predicts that hosts and pathogens will evolve higher resistance and aggressiveness in syst... more Theory predicts that hosts and pathogens will evolve higher resistance and aggressiveness in systems where populations are spatially connected than in situations where populations are isolated and dispersal is more local. In a large cross-inoculation experiment we surveyed patterns of host resistance and pathogen infectivity in anther-smut diseased Viscaria alpina populations from three contrasting areas where populations range from continuous, through patchy but spatially connected to highly isolated demes. In agreement with theory, isolated populations of V. alpina were more susceptible on average than either patchily distributed or continuous populations. While increased dispersal in connected systems increases disease spread, it may also increase host gene flow and the potential for greater host resistance to evolve. In the Viscaria-Microbotryum system, pathogen infectivity mirrored patterns of host resistance with strains from the isolated populations being the least infective ...
Neutral gene diversity in the range margins of an obligate fungal pathogen: Microbotryum violaceum on Silene dioica
Neutral gene diversity in the range margins of an obligate fungal pathogen : Microbotryum violace... more Neutral gene diversity in the range margins of an obligate fungal pathogen : Microbotryum violaceum on Silene dioica
Genetic architecture of biochemical resistance to the anther smut Microbotryum violaceum in Silene dioica
Genetic architecture of biochemical resistance to the anther smut Microbotryum violaceum in Silen... more Genetic architecture of biochemical resistance to the anther smut Microbotryum violaceum in Silene dioica
Our knowledge of aquatic fungal communities, their assembly, distributions and ecological roles i... more Our knowledge of aquatic fungal communities, their assembly, distributions and ecological roles in marine ecosystems is scarce. Hence, we aimed to investigate fungal metacommunities of coastal habitats in a subarctic zone (northern Baltic Sea, Sweden). Using a novel joint species distribution model and network approach, we quantified the importance of biotic associations contributing to the assembly of mycoplankton, further, detected potential biotic interactions between fungi–algae pairs, respectively. Our long-read metabarcoding approach identified 504 fungal taxa, of which a dominant fraction (44.8 %) was assigned as early-diverging fungi (i.e., Cryptomycota and Chytridiomycota). Alpha diversity of mycoplankton declined and community compositions changed along inlet–bay– offshore transects. The distributions of most fungi were rather influenced by spatial factors than by environmental drivers, and the influence of biotic associations was pronounced when environmental filtering wa...
Race-specific and spatially variable resistance to Microbotryum violaceum, a systemic anther smut disease in Silene dioica metapopulations
Race-specific and spatially variable resistance to Microbotryum violaceum, a systemic anther smut... more Race-specific and spatially variable resistance to Microbotryum violaceum, a systemic anther smut disease in Silene dioica metapopulations
Plant disease and islands
Questions: How do disease transmission rates, host longevity, and spatial structure interact to d... more Questions: How do disease transmission rates, host longevity, and spatial structure interact to determine disease dynamics and evolution of host resistance in systems where host sterility is the major consequence of infection? Features of model: A spatially explicit two-dimensional simulation model with deterministic within-population birth and death processes, but stochastic among-population dispersal. The model assumes frequency-dependent disease transmission, and is loosely based on the pollinator-transmitted anther-smut fungus Microbotryum violaceum, which infects and sterilizes host plants in the Caryophyllaceae. Resistance varies among host individuals and is associated with a fitness cost. Ranges of key variables: Simulations were run over ranges of host death rates, disease transmission rates, and spatial structures observed in natural host species. Conclusions: The simulation model predicts that: (i) increasing host longevity and connectivity of host patches is likely to select for pathogen strains with lower transmission rates; (ii) when hosts are short-lived or populations are isolated, susceptible genotypes with higher reproductive output may have a selective advantage even when disease is widespread; (iii) when hosts are longer-lived or populations are more connected, resistance costs are lower and resistance can evolve to higher levels. Existing data from natural host-pathogen systems support these conclusions, although predictions about resistance patterns need to be tested in future studies.
Ecological Research, 2014
We hypothesized a geographical pattern of the plant performance (seedling development, biomass pr... more We hypothesized a geographical pattern of the plant performance (seedling development, biomass production, relative water content and chlorophyll content) as a result of response to the interaction between photoperiod and water availability in populations of the arctic-alpine Silene suecica from different latitudes, thus experiencing different photoperiods during the growing season. Particularly, we expected a lower drought sensitivity in northern compared to southern populations as a consequence of harsher conditions experienced by the northern populations in terms of water availability. The experiment was carried out under common garden conditions, manipulating the water availability (wet and dry) and the photoperiod (21 and 16 h). We found an interaction between photoperiod and water availability on plant height, leaves, growth, biomass and total chlorophyll. However, the photoperiod neither counteracted nor intensified the effect of drought. Plants exposed to drought compensated for decreasing water availability by reducing their shoot growth. Changes in the chlorophyll content and chlorophyll a/b ratio were observed. Northern populations showed a higher basal growth performance and a greater response to the changed water regime (from wet to dry) than the southern populations. Southern populations showed a reduced ability to respond to drought, but their low basal performance may be advantageous under low water availability, avoiding water loss. In contrast, northern populations showed a stronger plastic response that limited the negative effects of reduced water availability. This study highlights the possibility that the plant response to environmental constraints (specifically water availability) may follow a geographical pattern.
Disease dynamics, host specificity and pathogen persistence in isolated host populations
Oikos, 2006
In situations where populations of related host species grow sympatrically but isolated from othe... more In situations where populations of related host species grow sympatrically but isolated from other populations of either host, cross-species disease transmission can have large influences on disease dynamic and patterns of pathogen persistence. This study examined host–pathogen dynamics and the degree of host-specificity in the anther-smut fungus Microbotryum violaceum at a site where two of its host species, Lychnis alpina and Silene rupestris, grew in adjacent patches which were located at large distances from the nearest intra-specific host and pathogen populations. In a field-study carried out over a four-year period in the sympatric populations, the two host species exhibited broadly parallel patterns of mortality and recruitment across years, although higher rates of mortality and infection, and larger fluctuations in numbers of plants, were seen in the S. rupestris population. However, when the frequency of disease in the populations was taken into account, disease transmission rates were relatively similar in the two hosts. In a reciprocal cross-inoculation experiment, there were no differences in infectivity between the two fungal populations on progeny of the two hosts from the sympatric populations indicating that cross-species disease transmission is possible. Patterns of infectivity on plants from the sympatric populations and allopatric populations of each host indicated the occurrence of a host shift in M. violaceum from L. alpina onto S. rupestris at the sympatric site. Results from a population model, parameterised with the demographic data from the two hosts, demonstrated that some cross-species disease transmission could increase the frequency of disease and lower the threshold level of pathogen persistence in populations. The population model also suggests that high levels of juvenile infection, as observed in both hosts, may increase the probability of pathogen persistence in local populations, especially in the more short-lived S. rupestris.
Anther-Smut Infection in Silene dioica: Variation in Floral Morphology and Patterns of Spore Deposition
Oikos, 1993
... Study sites We studied plants from the Skeppsvik archipelago at the river Savaran on the Gulf... more ... Study sites We studied plants from the Skeppsvik archipelago at the river Savaran on the Gulf of Bothnia (in Savar parish, Vasterbotten province, Sweden 63?44-48'N, 20?31-33'E (see description in Carlsson et al. 1990, Carlsson and Elmqvist 1992). ...
Uploads
Papers by Ulla Carlsson-Granér