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Enhancing rapeseed seedcake quality for feed and food using CRISPR-Cas RNP gene editing
Get PDFRapeseed is primarily grown for oil production, but its seed meal (RSM) is a valuable by-product rich in high-quality protein with potential for high-quality feed and food applications. However, its use in animal feed is limited by antinutritional factors, including glucosinolates (GSLs), sinapine, and phytic acid (PA), which impair nutrient uptake, reduce palatability, and negatively affect animal health. Due to the lack of natural genetic variation in these traits, traditional breeding has reached a plateau, while conventional genetic modification faces regulatory restrictions. To overcome these challenges and accelerate crop improvement, protoplast-based CRISPR RNP gene editing offers a promising transgene-free approach. However, a limitation in implementing this type of CRISPR gene editing in rapeseed is the regeneration of protoplasts into plants.
In this thesis, we developed an efficient regeneration protocol for rapeseed protoplasts, enabling the application of transgene-free CRISPR gene editing to reduce the levels of antinutritional factors. By targeting key genes involved in their biosynthesis and transport, we achieved high mutation efficiency and successfully edited multiple gene copies simultaneously. Knockout of GSL transporter genes (BnGTRs) reduced GSL content by up to 64%. Mutants of sinapine biosynthesis genes (BnSGT, BnSCT, and BnREF1) showed reductions of 45%, 31%, and 73%, respectively, with BnREF1 emerging as the most effective target gene. Additionally, disruption of BnITPK1 and BnITPK4 in the PA biosynthesis pathway led to PA reductions of up to 32% and 62%, respectively. These findings establish a strong foundation for transgene-free gene editing in rapeseed and highlight its potential for enhancing RSM’s nutritional value and agricultural viability
A comprehensive library of lifetime physiological equations for PBK models: Enhancing dietary exposure modeling with mercury as a case study
Get PDFDietary risk assessment of food contaminants requires a well-established understanding of the exposure in a heterogeneous population. There are many methods for estimating human exposure to food contaminants, such as intake calculations and internal biomarkers of exposure measured in individuals. However, those methods are expensive, partly invasive, and often provide a momentary exposure snapshot. Physiologically Based Kinetic (PBK) modelling is increasingly used to overcome those challenges that traditional human exposure methods encounter. Still, PBK models are often restricted to certain life stages (e.g., children, adolescents, adults). This study outlines a strategy for implementing nonlinear organ growths in age-specific PBK models to enhance dietary risk assessment from lifetime exposure. To this end, lifetime physiological equations calculating organ growth for both sexes were inventoried from literature and a library was established for 24 organs. We then assessed total lifelong mercury exposure via foodstuff by combining two existing age-specific PBK models for methylmercury (MeHg) and inorganic mercury (iHg) that simulated internal exposure to total mercury, the speciation typically measured in hair and urine. We implemented a set of physiological equations in the PBK model that fitted best the total mercury measured in individuals' organs, hair, and urine from heterogeneous populations. For refined dietary risk assessment, we ultimately estimated total mercury concentration in hair and urine based on i) maximum limits defined by the regulation for MeHg in seafood, ii) the health-based guidance values for MeHg and iHg, and iii) realistic intakes considering French demographic parameters and food consumption data. These exposure scenarios demonstrated that total mercury concentrations in hair and urine estimated from realistic intakes are below critical effect level measures at all ages. The result of this study is the creation of easily accessible tools in Excel and R that facilitate the implementation of physiological equations in Next Generation PBK models
An Emerging Role for Ticks as Vectors of Tularaemia in Sweden
Get PDFBackgroundThe zoonotic bacterium Francisella tularensis, the causative agent of tularaemia, can be transmitted to humans via multiple routes, including through contact with infected animals, contaminated water or arthropod vectors. Ticks have not previously been described as transmitting the disease in Sweden. Recently, Ixodid tick species have expanded their latitudinal and altitudinal range in Sweden to areas where the disease is endemic. Tularaemia is a cause of growing concern, spreading to new areas in Sweden and infecting hares and humans.ObjectivesTo establish whether ticks could be a potential arthropod vector in the transmission of F. tularensis subsp. holarctica in Sweden.MethodsTicks were collected from northern Sweden and screened for F. tularensis. A follow-up study with ticks collected from F. tularensis-positive hares was performed. Ticks were analysed using real-time PCR and a pathological examination was performed on the hares.ResultsF. tularensis subsp. holarctica was identified in ticks from one cat and three F. tularensis-infected hares. Two hares had skin lesions associated with tick bites with intralesional F. tularensis bacteria.ConclusionsF. tularensis subsp. holarctica was isolated from ticks collected from the hares and cat, the first such reports in ticks in Sweden. Identification of the bacteria at the tick bite site and the more chronic character of the skin lesions compared to those of inner organs suggest that the ticks infected the hares. The cat showed no clinical signs of disease, suggesting that its tick was indeed the vector. These new findings suggest that ticks play a role in the transmission of F. tularensis to human and animal hosts in Sweden
Struggling towards co-existence of the Baltic Sea coastal fisheries and the grey seal
Get PDFCommercial small-scale fisheries along the Baltic Sea coasts have declined over the years although these fisheries are viewed as important for coastal development and food security at the local, national, and EU levels. The viability and future of small-scale fisheries are severely challenged by problems caused by grey seals. The conflict, occurring between Baltic Sea coastal fisheries and conservation of the grey seals, has been severe since the mid-1990s and continues despite attempts to find a more balanced situation. Resting on reviews of multiple material, this paper explores the state-of-the-art opportunities for mitigating the seal-fisheries conflict and asks how these are related to social struggles and social justice. Our paper concludes that co-existence of coastal fisheries and the grey seal is possible but necessitates political will and co-designed seal management plans that help implement context-specific measures. Seal deterrents, for instance, give hope as a supplementary conflict mitigation measure - along with seal-proof fishing gear - but provide only partial relief. From the fisheries sector's position, influencing the size of the seal population is a logical solution. The lifting of the EU trade ban of seal products as a regional derogation would allow sustainable management of seal populations so that they be used as renewable natural resource. Monitoring changes in the seal population is crucial for maintaining a balanced population. Reaching co-existence is timely, because - unlike the seal - the diverse Baltic coastal fishing culture is increasingly endangered
A reinvestigation of cognitive styles in sticklebacks: decision success varies with behavioral type
Get PDFThe "cognitive styles" hypothesis suggests that individual differences in behavior are associated with variation in cognitive performance via underlying speed-accuracy trade-offs. While this is supported, in part, by a growing body of evidence, some studies did not find the expected relationships between behavioral type and cognitive performance. In some cases, this may reflect methodological limitations rather than the absence of a true relationship. The physical design of the testing arena and the number of choices offered in an assay can hinder our ability to detect inter-individual differences in cognitive performance. Here, we re-investigated the cognitive styles hypothesis in threespine stickleback (Gasterosteus aculeatus), adapting the maze design of a previous study which found no cost to decision success by faster (bolder) individuals. We used a similar design but increased the size of the maze and incorporated an additional choice in the form of a third maze arm. We found, in accordance with cognitive style expectations, that individuals who were consistently slower to emerge from the start chamber made fewer errors than fish that emerged faster. Activity in an open field test, however, did not show evidence of a relationship with decision success, possibly due to the low number of repeated observations per fish in this separate assay. Our results provide further empirical support for the cognitive styles hypothesis and highlight important methodological aspects to consider in studies of inter-individual differences in cognition.Inter-individual variation in cognitive ability is hypothesized to be associated with behavioral traits through trade-offs between speed and performance. Previous research testing a common model species-the stickleback-did not find evidence to support the expected relationship between decision success and behavioral type. Using a more challenging test, with an additional choice and larger maze, we found that individuals that emerge faster (i.e. "bolder") were also more error-prone, as predicted by the cognitive style hypothesis
Winter wheat-soybean relay intercropping in conjunction with a shift in sowing dates as a climate change adaptation and mitigation strategy for crop production in Germany
Get PDFContext: Given the negative impacts of climate change on crop production, it is vital to implement efficient adaptation and mitigation strategies. The diversification of cropping systems, particularly through intercropping combined with shifts in sowing times, could have the potential to offset such negative impacts. Yet, both experimental data and simulation studies are scarce to elucidate the intercropping performance under future climate change conditions, particularly for evaluating its potential to offset climate impacts on crop and protein yields in German wheat-based systems. Objective: This study aimed to simulate the grain yield and grain protein performance of winter wheat-soybean relay-row intercropping across Germany under future climate conditions, comparing it to sole cropping systems. Methods: We employed the MONICA agroecosystem model and its intercropping module to simulate the performance of an innovative winter wheat-soybean relay intercropping system. This was in combination with a wide range of shifts in sowing dates, and we compared it against standard sole cropping under low and high emission scenarios across Germany. Results: The model projected a 15% higher sole wheat yield under the future (2031-2060) high emission scenario than that of the historical period (1981-2020), while sole soybean yield increased by 8% in the same case. Although the simulation of winter wheat-soybean relay intercropping across Germany indicated a 9 % yield penalty compared to sole cropping in the future, with a transgressive overyielding index of 0.91, intercropping emerged as particularly advantageous in terms of land-use efficiency and protein production. It saved 17 % of land compared to sole cropping, thus produced equal amounts of grain yield, and produced 16% more protein than sole cropping in the high emission scenario. On top of that, shifting the sowing dates of the component crops to earlier times was found to substantially enhance the advantages of intercropping, resulting in a maximum of 44 % higher total yield production, and 47 % higher protein production than sole wheat without shifting sowing date in the future projection window. Conclusion: Our findings highlight the grain yield and protein production potential of intercropping versus sole cropping under futuristic high emission scenarios (RCP 8.5), and underscoring its potential to create a win-win situation of increased crop diversity and productivity. The results affirm the crucial importance of selecting optimal sowing dates for the component crops in intercropping, to maximize production and ensure resilience in the face of a changing climate
Rebalancing River Lateral Connectivity: An Interdisciplinary Focus for Research and Management
Get PDFLateral connectivity between rivers and terrestrial landscapes is critical for both river and landscape health. Due to widespread anthropogenic degradation of riverscapes, river management is aiming to connect rivers to floodplains, riparian zones, and wetlands, putting a spotlight on lateral connectivity. However, there is currently no consensus on how to conceptualize and study lateral connectivity in rivers across disciplines. Here, we review lateral connectivity between riverscapes and terrestrial landscapes. We focus on the natural sciences, considering hydrology, geomorphology, ecology and biogeochemistry, but also consider social connectivity and the management and restoration of lateral connectivity. We emphasize the importance of considering the bidirectional nature of lateral connectivity, operating both into and out of river channels and the balance between these directions. The resulting "lateral connectivity balance" provides a framework to understand natural spatial and temporal variability in connectivity. Anthropogenic impacts have swung the balance of lateral connectivity, enhancing the transport of materials into and through river networks while suppressing fluxes from rivers to adjacent landscapes. We conclude that further research at the interfaces between the aquatic and terrestrial components of riverscapes is critical to advance our conceptual understanding of river and catchment systems. We propose that such research should be framed within the paradigm of "rebalancing" lateral connectivity, explicitly recognizing the natural bidirectionality of laterally connecting processes, the significance of the hydrologic, geomorphic, and biologic functions they support, and the value to society of the ecosystem services and climate change resilience they provide
Effects of fire intensity on carbon dioxide exchange in an arctic dry heath tundra
Get PDFThe frequency and intensity of wildfires in the Arctic has been increasing due to climate change. However, little is known about the effects of fire intensity on carbon dioxide (CO2) exchange in arctic tundra ecosystems. To investigate this, we conducted an experimental fire with different burn intensities (low intensity, high intensity, and unburned control) and measured surface daytime CO2 fluxes over four growing seasons in a dry heath tundra in West Greenland. We found that post-fire soil temperatures and moisture increased with increasing fire intensity, by up to 2.2 degrees C and 18 vol%, respectively. Fire had no effects on soil microbial biomass independent of intensity. The high-intensity fire increased soil nitrate concentrations only immediately after the fire. The ecosystem shifted from a net CO2 sink to a net CO2 source immediately after the fire, due to the reduced gross ecosystem production. One year after the fire, the low-intensity burned plots became a net CO2 sink, while the high-intensity burned plots remained a net CO2 source throughout the study period. This suggests that the time needed for the ecosystem to become a net CO2 sink increases with fire intensity. Fire intensity had no effect on soil respiration, but the high-intensity fire significantly reduced ecosystem respiration (ER) rates one and three years after the fire. This suggests that decreased ER was mainly driven by the reduced aboveground plant respiration. Over four growing seasons after the high-intensity fire, cumulated post-fire C losses exceeded the C losses during the fire. Thus, it is essential to consider the long-term C losses following fire to improve understanding of wildfire impacts on arctic tundra C dynamics. Overall, this study highlights that high-intensity fires prolong the duration of burned areas as a net CO2 source, leading to increased post-fire CO2 emissions, when compared to low-intensity fires
Electrical Phenomena in Trees and Wood: A Review
Get PDFPurpose of review This review covers electrical phenomena originating from the physical properties of wood, relevant to tree biology and timber industry applications. Membrane-associated cellular phenomena like action potentials are excluded. Trees exhibit diverse bioelectric processes of physical origin. The electrical properties of wood hold promise for advancing timber processing, and developing smart materials, while enhancing our understanding of tree-environment interactions.Recent findings Streaming and piezoelectric potentials have long histories but are now reinterpreted based on our better understanding of plants. Streaming potentials from sap flow, discounted in the 2000s, have been reinstated through recent publications addressing past inconsistencies with current data on xylem structure. Electro-osmotic flow is gaining new applications in timber drying. Wood, previously considered weakly piezoelectric, shows much stronger activity after fungal degradation, spurring interest in practical applications and the underlying mechanism - now better understood through new findings on the structure, deposition and deformation of wood cellulose. Internal variation in the electric (conductive and dielectric) properties of green logs facilitates innovative timber quality mapping methods. Emerging research on perturbation of the atmospheric and soil electric fields by trees offers insights into inter-organism interactions.SummaryThis review encompasses electrical measurement methods; electrokinetic phenomena, including streaming potentials and electro-osmotic timber drying; electric heating; mapping and technologies based on dielectric properties; wood-based electronics; electromechanical phenomena, including the piezoelectric effect and triboelectrification; atmospheric electricity around trees; and electrotaxis. Future research should explore electro-osmosis in wood and its applications. Electric potentials in green wood and living trees, generated through ion-transport mechanisms, need further exploration to elucidate charge separation processes
