Czechia

Plants in the natural environment experience continuous dynamic changes in light intensity. We have limited understanding on how plants adapt to such variable conditions. Here, we exposed Arabidopsis thaliana plants to naturally fluctuating light regimes alongside traditional square light regimes such as those often found in control environment growth chambers. The physiological response was highly consistent across experiments, indicating the involvement of an epigenetic mechanism, leading us to investigated differences in DNA methylation. Our results identified a large number of alterations in DNA methylation patterns between fluctuating light acclimated plants, and square light acclimated plants, demonstrating natural fluctuations in light impacts the plant epigenetic mechanisms. Most importantly, there are more differences in DNA methylation patterns between different light pattern regimes than between different light intensities. These differences in DNA methylation were accompanied by significant changes in gene expression, some of which correlated with altered DNA methylation. Interestingly, several transposable elements which displayed differential methylation were found to be differentially expressed between light regimes. Our data suggests DNA methylation plays a role in acclimation to natural light which may directly regulate gene expression and impact transposable element activation.

SEB Conference Prague 2024

DNA methylation contributes to plant acclimation to naturally fluctuating light

photosynthesis

acclimation

light

dna methylation

technical paper

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SEB’s Annual Conference is celebrated for creating the perfect composition of research, new discoveries and collaborative connections. Be creative and innovative by exchanging ideas and knowledge with masters of biology from all over the world.

Animals on Earth are naturally exposed to environmental fluctuations, including changes in temperature, food availability and food quality. Their capacity to adapt to these environmental variations may be challenged by anthropogenic stressors, including global warming, extreme weather events, and changes in land use. The capacity of individuals to produce and use energy is an essential parameter in determining animals’ ability to cope with these environmental changes. In my talk, I will discuss how environmental stressors affect energy allocation in animals, exemplifying with own work on birds and fish, with the overarching goal to identify broad synergies and divergences in response to environmental change amongst endotherms and ectotherms. I will highlight the value of studying changes in energy metabolism at various stages of life and biological levels of organisation, to understand the mechanisms by which endotherms and ectotherms may maintain fitness in a changing world.

Similar challenges but different consequences: how climate change shapes metabolic strategies in endotherms and ectotherms

Freshwater tolerance has evolved multiple times among stickleback fishes (Gasterosteidae), such that several closely related species differ in freshwater tolerance. The threespine and fourspine sticklebacks (Gasterosteus aculeatus and Apeltes quadracus) inhabit both freshwater and saltwater, while the blackspotted stickleback (Gasterosteus wheatlandi) and white threespine ecotype (Gasterosteus aculeatus) are largely restricted to saltwater habitats, despite being able to survive acute freshwater exposure as adults. We investigated whether the distribution of blackspotted and white threespine sticklebacks might be limited by a) their capacity to tolerate freshwater during vulnerable early life stages and/ or b) the winter-induced combined stressors of freshwater and cold temperature. The blackspotted stickleback’s fertilization success decreased by 75% in freshwater relative to saltwater, while the threespine and white threespine sticklebacks maintained similar fertilization success in both salinities. Once fertilized, all four species had high survivorship rates (~100%), similar development rates, and comparable metabolic rates (150-250umolO2/um) in freshwater. Overall, our results suggest that reproduction may limit freshwater colonization in this clade, but early life freshwater tolerance does not. In addition, overwintering of adults in freshwater environments may necessitate energetic expenditure that is unsustainable for non-freshwater-colonizing species. Indeed, a cold-induced decrease to their aerobic scope has been shown to occur in the threespine stickleback. To test whether such energetic limitation might restrict non-freshwater-colonizing species’ distributions, we are currently measuring aerobic scopes of threespine and blackspotted sticklebacks who experienced freshwater and saltwater, under winter (4°C) and summer (18°C) temperatures.

Does early life freshwater tolerance or adult tolerance of combined stressors limit freshwater colonization in stickleback fishes?

Nankeen kestrels (Falco cenchroides) have been trained to windhover in a wind tunnel. The presence of an updraft allows the kestrel to maintain a stationary hover without flapping. The kestrels were subjected to known and controlled vertical gusts, and their flight kinematics were tracked using motion-capture cameras. A dataset of 468 gust encounters has been recorded across a range of different gust profiles. Consistent trends were present in the movements of birds’ wings and tail in response to upwards and downwards step gusts. The delay times of the gust responses suggest that changes to wing dihedral, wing incidence, and tail incidence are passively initiated by aerodynamic loading rather than active muscle control. The study is ongoing, and it is hoped that insights gained will inspire the development of small unmanned aerial vehicles (UAVs) with greater steadiness and less flight-path divergence when encountering gusts and turbulence.

Kestrel kinematics during discrete gust encounters while windhovering in a wind tunnel

A paradox of avian long-distance migrations is that birds must greatly increase their body mass prior to departure, yet this is presumed to substantially increase their energy cost of flight, particularly given their tendency to fly relatively fast. However, our understanding of the interactive effects of speed and weight is limited on flight energy costs are based on a few constrained wind tunnel studies. The literature is missing experiments on free-ranging birds flying at similar speeds but with different body masses to test whether the additional energy costs of flying when heavier are very small as indicated by laboratory experiments, or are hyper-allometric as might be traditionally expected. We addressed this by undertaking a novel design of loading experiment on free-flying homing pigeons which utilised thin ventrally located weight and a heart rate data recorder. Our data show that when homing pigeons flying in a flock are loaded with ventral weight, both their heart rate and estimated energy expenditure barely rise. The net effect is that energy costs per unit time increase only slightly and per unit mass they decrease. We suggest that this is because homing pigeon flights are relatively fast, and consequently flight costs associated with increases in body parasite drag dominate over those of weight support, leading to an improvement in mass-specific flight economy. We propose that the small absolute aerodynamic penalty for carrying enlarged fuel stores and flight muscles during fast flight has helped to select for the evolution of long-distance migration.

Fat homing pigeons don't use more energy: an excellent animal model for investigating flight physiology in the wild

Global climate change is one of the most significant threats to biological diversity and survival. Coupled with increasing anthropogenic outflows and environmental devastation, temperate species must adapt or move north to maintain temperature homeostasis. Polar areas are the most critically impacted, with the Arctic warming several-fold faster than other areas. This alter ice coverage and permafrost depth, revealing deposits of critical minerals, including those used in battery technologies, such as zinc, cobalt, and nickel (Ni). In response to the growing demand for green energy technologies, significant extraction efforts have led to increased aquatic metal concentrations in the Arctic. Exploitation of these mineral resources allow for increased transport of these metals into Arctic waters, yet insufficient data exists regarding the impacts they may have on Arctic biota. This study aimed to address some of these knowledge gaps, with a particular interest in the impacts of Ni on Arctic char (Salvelinus alpinus). Arctic char are an important salmonid species in Arctic ecosystems, but the physiological responses of these fish to chronic Ni exposure remains unstudied. To address this, we exposed juvenile Arctic char to environmentally relevant Ni concentrations for sixty days to investigate the physiologic consequences of exposure and the mechanisms of toxic action. This work evaluated impacts on growth, survival, the respiratory system, and ionoregulation, finding significant impacts on both survival and growth, among other effects. These results provide insight into the physiological consequences of Ni exposure on Arctic char and the risk posed to these fish in their native environments.

Understanding the North: The physiologic repercussions of chronic nickel exposure to the Arctic Char (Salvelinus alpinus)

Artificial light at night (ALAN) is a globally pervasive sensory pollutant that disrupts biological processes across taxa and at all levels of organisation, but its impact on colour-guided processes remains largely unexplored. This is especially concerning given the rapid and ongoing transition away from narrow-spectrum lighting and towards broad-spectrum technologies like white LEDs, which are rich in the short wavelengths of light to which many taxa are especially sensitive. Camouflage is particularly likely to be disrupted by broader ALAN spectra, due to changes in the conspicuousness of background matching prey altering prey recognition in visually guided predators. We simulated natural intensities of moonlight with and without ALAN, using both broad-spectrum ALAN and ALAN filtered to remove the characteristic short wavelength peak of white LEDs to test how exposure to these light treatments impacted predator-prey interactions between the intertidal crab Carcinus maenas and contrasting morphs of the colour-polymorphic snail Littorina obtusata. Exposure to broad-spectrum ALAN reduced overall predation by more than half and reversed the pattern of colour-based prey selection observed under control conditions. Exposure to filtered ALAN removed any significant difference in attack likelihood between colour morphs. Our results demonstrate that spectral composition is a crucial aspect of ALAN as a sensory pollutant, capable of instigating profound changes in predator-prey interactions that could drive changes in population demography and increase morphological homogeneity in species that depend on colour polymorphism for camouflage.

Now you see me, now you don't: artificial light at night alters predation on colour-polymorphic camouflaged prey

Coral-dwelling fish experience large daily fluctuations in oxygen, with hyperoxia occurring during the day and hypoxia building up at night. Nighttime hypoxia can be particularly severe between the branches of corals and intensifies in warmer temperatures due to the high respiring biomass of many shelter-seeking organisms. The damselfish, Dascyllus aruanus, is one of the species that seeks shelter within corals and must tolerate hypoxia on a nightly basis. Here we use a combination of field dissolved oxygen measurements, in situ underwater video recordings on the coral reef, and lab experiments to ask whether Dascyllus aruanus has evolved specific behavioural (e.g., changes in activity and sheltering) and physiological (e.g. changes in vision) adaptations to enhance performance under hypoxia. We compare these results to the nocturnal cardinalfish Ostorhinchus angustatus, which rarely experiences hypoxia, and predict it lacks hypoxia-related adaptations. Given the anticipated rise in severe hypoxia occurrences, understanding these adaptations is crucial for assessing the resilience of these species to a changing climate. By using a variety of methods, we aim to gain a new perspective on how oxygen shapes the behaviour and physiology of coral reef fish.

Behavioural and physiological responses of coral reef fish to progressive hypoxia

In cereals, such as wheat and barley, crossing overs (CO) are distributed mainly at the end of chromosomes so that centromeric and pericentromeric regions that include up to 30% of the genes rarely, if ever, recombine. Thus, substantial proportions of the chromosomes are inherited together as large linkage blocks, preventing the generation of novel gene combinations and useful variation that could be exploited in breeding programmes. Therefore, an ability to modify the pattern of recombination in these species would have a profound impact on the breeding of these crops. In order to investigate means of altering the patterns of CO in barley, we have utilised SNP genotyping and cytological procedures, to investigate a collection of non-allelic desynaptic barley mutants. All the desynaptic mutants exhibited perturbed meiosis and semi-sterility compared to wild type with some exhibiting unexpected phenotypes during synapsis (Colas et al, 2016). Overall, studies have suggested a tighter control of meiotic progression of chromatin/meiotic axes compared to the model Arabidopsis.

Although the down-regulation of most meiotic genes leads to abnormal meiosis and loss of recombination, we have found a few variants that increase the number (and sometimes change the distribution) of recombination in barley. This is the case in HvST1 (Orr, Mittmann et al, 2023) HvRECQL4 (Arrieta et al, 2021) and a few TILLING mutants that are currently under investigation. Finally, we have characterised the barley meiosis transcriptome and proteome from cytologically staged anthers (Barakate et a, 2021; Lewandoska et al, 2022), which represent novel resources for cereal studies. The talk will discuss these findings and their potential use for plant breeding and future directions.


The control of Meiosis in large genome crop

With the emergence of increasingly complex learning models – discovery-based, hybrid and lifelong learning – we are invited to recognise the learning environment as more dynamic and broadly encompassing than the traditional classroom alone. Nonetheless, the examination of discovery-based learning has remained generally confined to formal timetabled contexts (Freeman et al., 2014). Student interactions in the times and spaces between timetabled classroom learning, including with members of the wider academic community, are increasingly acknowledged as pivotal for learning and sense of belonging. 

Given this growing complexity, our presentation introduces an ecological framework which offers a more holistic and dynamic view of the context of learning (Barnett & Jackson, 2019). The approach has helped a UK-based, science, technology, engineering, and mathematics (STEM), research-intensive university to understand its own challenges in the context of a strategic shift toward more student-centred discovery-based learning. The ecological thinking supported a research-informed transformation of various formal, transitional and informal learning spaces, whilst aiding the management of tensions between passive and active pedagogic practices. 

By conceptualising the learning environment and academic community as an interconnected ecosystem with a biodiversity of people and ideas, we might better harness the collective agency and research of universities to educate the future generation of students more effectively and sustainably.

Bridging the gap: an ecological approach to integrating research and practice

Environmental context is important for plant growth. In the field, plants are exposed to weather, seasons and also challenges due to climate change, while much of the high-throughput phenotyping of plants takes place in greenhouses and climate chambers, which limits knowledge transfer. To close this gap, the PhenoSphere was developed to enable researchers to assess plant phenotypes reproducibly under simulated field-like environments. In a benchmark experiment, the PhenoSphere was challenged to reproduce a single season and to simulate the mean of three consecutive seasons. Plant growth under these conditions was compared to that established during four years of field trials and an experiment in a greenhouse. This revealed that the single season simulation was closest to the template environment and field trials in general. It was found to be superior to the conditions in the greenhouse and the averaged season. Recently, the PhenoSphere was upgraded with the PhenoCrane, an automated multi-device imaging panel on a crane system, which allows high-throughput phenotyping by RGB-, hyperspectral-, and chlorophyll fluorescence imaging. Adopting the FAIR data principles enables the integration of the PhenoSphere into already established research infrastructures. By combining field-like growth conditions and large-volume soil containers with the PhenoCrane, we are now able to evaluate the performance of genetic variants in current and future climate scenarios.

DNA methylation contributes to plant acclimation to naturally fluctuating light

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Similar challenges but different consequences: how climate change shapes metabolic strategies in endotherms and ectotherms

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DNA methylation contributes to plant acclimation to naturally fluctuating light

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Next from SEB Conference Prague 2024

Similar challenges but different consequences: how climate change shapes metabolic strategies in endotherms and ectotherms

Stay up to date with the latest Underline news!

PRESENTATIONS

CONFERENCES

COMPANY

RESOURCES

Downloads