Dr. Ivan Oresnik
Department of Microbiology, University of Manitoba
Relationship between central carbon metabolism and nitrogen fixation in Sinorhizobium meliloti
Carbon metabolism is generally well understood in Sinorhizobium meliloti. The literature is consistent with the role of dicarboxylic acid metabolism while the bacteroid is actively fixing nitrogen. However, the literature contains many nitrogen fixation phenotypes ascribed to mutants that encode enzymes in central carbon metabolism that make little sense, or are even paradoxical. For example, a mutation in pckA, which is necessary for gluconeogenesis and encodes phosphoenolpyruvate carboxy kinase, consistently gives nitrogen fixation rates that are approximately 50% of wild-type, yet no measurable enzyme activity can be detected in bacteroids. Similarly, our work has shown strains that do not have triose phosphate isomerase activity also yield plants with 50% dry matter accumulation when grown under nitrogen deficient conditions. To date there is no clear explanation why these lesions affect nitrogen fixation based on our current knowledge. Based on our observations, we are hypothesizing that carbon metabolism may be correlated with endoreplication during bacteroid development and that rates of nitrogen fixation may be linked to the copy number of genes directly involved in nitrogen fixation. Although this may explain what occurs in indeterminate nodules, it probably does not apply to determinate nodules, suggesting that what limits nitrogen fixation between these nodule types may be different.
MSc, Yakimowski Lab
Estimating the stability and heritability of resistance fueling copy number variation in glyphosate-resistant Amaranthus palmeri
Copy number variation (CNV), especially when present in extrachromosomal fashion, provides unparalleled opportunity for speciation and adaptation. As observed in agricultural weed species, Amaranthus palmeri, CNV of the herbicide glyphosate’s target gene, EPSPS, has resulted in emergence of glyphosate-tolerant and resistant populations across the globe. The amplification of EPSPS copies in forms of extrachromosomal circular DNA (eccDNA) poses unique challenges when assessing the heritability of EPSPS CNV as its origin and the tethering mechanisms are still mostly unknown. I used 30 F0 pairs and 900 F1 individuals from glyphosate-resistant populations to examine the heritability of EPSPS CNV in relation to parental EPSPS CNV. The results display a shifting pattern in progeny CNV with increasing parental mean EPSPS copy number. Over 70% of progeny resulting from parental crosses of low-med CNV displayed an increase in EPSPS CNV in a single generation while the opposite pattern was observed in progeny resulting from high EPSPS CNV mean parental crosses. This result indicates a substantial decline in heritability after a threshold point of 48.8 mean parental EPSPS CNV. The weaker heritability of eccDNA gene copy number variation at high CNV suggests weak evolutionary potential of highly glyphosate resistant CNV individuals and may constrain the evolution of population EPSPS CNV mean.
Dr. Megan Bontrager
Department of Ecology & Evolutionary Biology at University of Toronto
Local adaptation at range edges and under anomalous climates
Species’ geographic ranges are limited on the landscape. A major focus of work in the Bontrager lab is identifying which evolutionary and ecological forces interact to shape species’ geographic distributions and limit adaptation. In addition, populations are frequently adapted to their local environments, and my lab works to identify which components of the environment are the most important factors driving local adaptation. I will talk about how gene flow affects range edge populations and how these effects may be especially important under climate change. I will also present results from two quantitative syntheses of transplant experiments to 1) examine how climate change is altering patterns of local adaptation, 2) evaluate the relative importance of temperature and precipitation to local adaptation and 3) examine how the magnitude of local adaptation changes from range centres to range edges. This work explores critical drivers of plant population performance and characterizes patterns of adaptation across species' ranges.
PhD, Eckert Lab
Long-term experimental analysis of ecological and evolutionary processes at a species’ range limit
Why do species have stable range limits – and what happens if they break free? Many species’ geographic ranges have historically been stable in space, but they may shift as climate change alters habitats. My thesis first looks at why species have stable range limits; what prevents them from dispersing beyond their ranges and adapting to the new habitat? I briefly review the current state of the field of range limits and provide a novel long-term test of whether a species’ range is limited by its niche. Next, I examine a few things that might happen if species shift their ranges using a beyond-range transplant experiment with the best coastal dune plant, Camissoniopsis cheiranthifolia. First, I ask: are populations from the range center or edge better suited to establish in beyond-range habitat? And second: did populations adapt to beyond-range conditions over ten generations? Finally, I test whether local or genetically mixed populations perform best within the range, to inform conservation efforts to re-establish populations and restore habitats. Come to my talk to learn about the mechanisms stopping species from expanding their ranges, some of the ecological and evolutionary processes going on during range shifts, and which populations are best used for conservation efforts like assisted migration and habitat restoration! (The photo is me with my first flowering transplant in 2018.)
MSc, Snedden Lab
Investigating the interaction of Arabidopsis calmodulin-like (CML) proteins with calmodulin-binding transcription activators (CAMTAs)
Understanding the how organisms detect and interpret information from their environment is an ongoing goal in cell biology. A common theme among eukaryotic cells is the use of calcium ions (Ca2+) as second messengers during information processing. In plants, Ca2+ signals are evoked during responses to abiotic and biotic stresses and during development. These signals are detected by Ca2+-binding proteins (sensors), such as the evolutionarily-conserved protein calmodulin (CaM), which regulates various downstream target proteins to organize signal transduction pathways. In addition to CaM, plants have evolved a remarkable array of CaM-like proteins (CMLs) that are not found in animals. The genetic model, Arabidopsis, has seven CaMs and 50 CMLs, most of which remain unstudied. Why do plants need so many of these Ca2+ sensors? What are their downstream targets? How do they contribute to Ca2+ signaling during stimulus response? Research on CML structure/function is needed to develop a broader understanding of how plants respond to environmental cues. Recently, our lab has been exploring the roles of two paralogs, CML13,14, which possess unique biochemical properties among CaMs and CMLs. To help uncover CML13,14 function, we screened a yeast 2-hybrid library for putative target proteins and discovered 3 families of functionally unrelated proteins that share a common structural feature; tandem IQ domains. IQs are unique CaM binding domains that have been mainly studied in the myosin motor proteins of animals. In addition to myosins, we identified several CaM-binding transcription activators (CAMTAs) as putative CML13,14 targets. CAMTAs possess multiple IQ domains and are important transcription factors in plants that regulate gene expression during abiotic and biotic stresses such as cold, drought, salt stress, pathogen attack, and herbivory. I will present data from my MSc project where I explored the question; are Arabidopsis CAMTAs targets of CML13,14? My project focused mainly on assessing the properties of CML13/14-CAMTA binding, using both in planta and in vitro methods. Using a genetic approach, I also discovered a key role in salinity stress response for CML13. Collectively, my data supports the hypothesis that CAMTAs and CMLs interact in plants and suggests a novel mechanism through which Ca2+ signals regulate gene expression during stress response.
Dr. Anusha Shankar
Lab of Ornithology at Cornell University
Hot and cold hummingbirds: The ecology, physiology and genes of cold endotherms
Information about Dr. Anusha Shankar here
Hummingbirds live fast. They have among the highest metabolic rates of all vertebrates, and must eat constantly to stay alive. I will talk about some of what I have learned about how they manage their energy budgets during the day, and how they allocate time and energy to different activities based on changes in their environment. At night, they save energy by entering the fascinating hibernation-like state of torpor. How do they manage to get so cold (~50°F/10°C) and slow their metabolism down as much as they do, and stay alive? This is what I am currently working on finding out. My work integrates methods and approaches from ecology, physiology and transcriptomics to understand how these tiny endotherms manage to survive in a variety of environmental conditions.
MSc, Smol Lab
Assessing the impacts of emerging anthropogenic stressors on lakes within the Rideau Canal system: A paleolimnological re-assessment
Earlier diatom-based paleolimnological studies were conducted on a suite of diverse lakes (i.e., Lower Rideau L., Big Rideau L., Otter L., Upper Rideau L., Indian L., L. Opinicon) within the Rideau Canal system ~25-30 years ago and provided important information regarding the ecological impacts of canal construction (1827-1832). Following these early paleolimnological studies, the same lakes are now facing the potential impacts of newly emerging environmental stressors, particularly accelerated climate warming. Here, I revisited the same suite of lakes by conducting a series of paleolimnological analyses, focusing on recent changes in diatom assemblage composition, to assess the potential ecological impacts of newly emerging environmental stressors. Despite the substantial environmental impacts associated with canal construction, the highest rate of diatom compositional change across the suite of lakes only took place in the past ~25-30 years, which coincided mainly with an increase in planktonic diatom taxa. This recent shift in assemblage composition could not be explained by nutrient enrichment, as total phosphorus (TP) concentrations, measured since the 1980s, have significantly declined across the study lakes. The continued increase of planktonic taxa across the study lakes suggests the impact invasive zebra (ca. 1990) mussels in the Rideau Canal region appeared to have only been modest. Rather, these recent changes in diatom assemblage composition were strongly related to increasing regional air temperatures, as the conditions associated with warmer temperatures (i.e., longer, and stronger periods of thermal stratification, alterations to water-column mixing regimes, reduced ice cover duration) provide favorable conditions for extensive planktonic diatom growth. Lakes within the Rideau Canal system are changing rapidly in ecologically significant ways and will likely continue to do so as temperatures continue to rise.
MSc Candidate, Regan Lab
Exploring the cellular basis of environmental stress and plant development: Bioremediation potential of Senna and gene function in Populus
As of 2021, the earth holds about 3.04 trillion trees. Plants account for 80% of the world’s total biomass. Trees, and plants in general, inherently play very important roles in our daily lives. My thesis examines the potential of a plant, Senna occidentalis, to phytoremediate arsenic- and cadmium-contaminated soils. Additionally, my thesis advances our understanding of leaf and stem development though the analysis of a mutant line of Populus tremula x Populus alba called shriveled leaf.
MSc Candidate, Colautti Lab
Genetic exploration of two invasive species to study rapid evolution and invasion genetics
Classical genetics entails the study of spontaneous or introduced genomic mutations, analyzing the corresponding phenotypes, and then identifying the affected genes. Today's research is based on reverse genetics, which starts with the gene sequence and then explores its functions by analyzing the phenotype of an induced mutation. But how do we move from that specific phenotype to analyze fitness in a population?
Ecological genetics approach goes the other direction, observing the impact of a phenomenon in an ecosystem and analyzing community interactions, population dynamics, fitness, and observing a particular phenotype that may be of interest. There are not many studies that analyze the genes associated with a phenotype in the context of a natural community. In other words, how do we go from studying ecosystem diversity to genetic diversity?
Invasive species provide the opportunity to study the expression of genes in populations subject to a changing environment. Since invasive species are known to adapt quickly and spread rapidly thus posing a threat to native ecosystems, more information on the genetic mechanisms of invasion can give us clues to how natural species can adapt to rapid changes, including under future climate change scenarios.
My research provides evidence for the functional annotation of the draft genomes of Alliaria petiolata (garlic mustard) and Lythrum salicaria (purple loosestrife). These two plant species of Eurasian origin have successfully invaded and spread across North America. Each species has characteristics that make them valuable as a model for invasion. Alliaria petiolata belongs to the family Brassicaceae and dominates forest understories in absence of disturbance and produces glucosinolates and flavonoids as defensive chemicals that affect the growth of competitors. In contrast, L. salicaria belongs to the family Lythraceae, invades wetlands and has rapidly evolved differences in flowering time to adapt to differences in season length. Both species are highly prolific with the difference that L. salicaria is an obligate outcrossed, so populations maintain a higher level of genetic variation in comparison with A. petiolata which is known to have a comparatively higher rate of self fertilization.
Using the draft genomes of both species as a reference, my research has focused on the assembly and analysis of the transcriptome (RNA) of samples from different conditions. For A. petiolata, RNA was extracted from leaf and root samples from individual plants subjected to mechanical injury and exposed to jasmonic acid to mimic herbivory. From these data candidate genes could be identified as potentially having a role in defense metabolic pathways. For L. salicaria, RNA was extracted from floral tissue of early and late flowering plants to predict candidate genes associated with flowering time. Using this new information, the draft genome annotations assemblies can be further improved, which will enable future molecular and functional genomic studies to investigate the genetic mechanisms of invasion and rapid adaptation in novel environments.
French National Research Institute of Agronomy and Environment (INRAE)
Peer Community In: A free alternative to evaluate, validate (and publish?) preprint
:The Peer Community in (PCI, https://peercommunityin.org) project offers an alternative to the current system of publication - which is particularly expensive and not transparent. PCI is a non-profit scientific organization that aims to create specific communities of researchers reviewing and recommending, for free, unpublished preprints in their field (i.e. unpublished articles deposited on open online archives like arXiv.org and bioRxiv.org). Each PCI is a group of several hundred recommenders playing the role of editors who recommend such preprints based on peer-reviews to make them complete, reliable and citable articles, without the need for publication in ‘traditional’ journals (although the authors can submit their recommended preprints afterwards). Evaluations and recommendations by a PCI are free of charge. When a recommender decides to recommend a preprint, they write a recommendation text that is published along with all the editorial correspondence (reviews, recommender's decisions, authors’ replies) by PCI. The preprint itself is not published by PCI: it remains in the preprint server where it has been posted by the authors and can therefore be submitted to a journal and publish in Peer Community Journal, an open access diamond journal that PCI will launch, this fall. The first Peer Community in has been launched in 2017: Peer Community in Evolutionary Biology (PCI Evol Biol). PCI genomics was created two years ago. More than 1200 recommenders have already joined PCI Evol Biol, PCI Genomics, PCI Paleontology, PCI Ecology, PCI Animal Science, PCI Zoology, PCI Mathematical and Computational Biology, PCI Archaeology, etc. PCI won the 2020 LIBER award for library innovation of the European League of Research Libraries.
Thomas Guillemaud is a senior scientist at the French National Institute for Research in Agronomy and environment (INRAE). He works in Sophia Antipolis, France, on the evolutionary biology aspects of biological invasions. He obtained his phD a long time ago in the Institute for Evolutionary Biology of the university of Montpellier, France. He co-founded PCI in late 2016 and co-manages PCI since then.
Denis Bourguet is a senior scientist at the French National Institute for Research in Agronomy and environment (INRAE). He works in Montpellier, France, in evolutionary biology on pesticide resistance evolution. He obtained his phD a long time ago in the Institute for Evolutionary Biology of the university of Montpellier, France. He co-founded PCI in late 2016 and co-manages PCI since then.
MSc Candidate, Bonier Lab
Among-species variation in hormone concentrations is associated with urban occurrence in birds
Urbanization of natural areas is increasing worldwide, contributing to rapid biodiversity loss. While most wildlife disappears as habitat becomes urbanized, some species survive and even thrive in cities, though the traits that allow them to do so remain poorly understood. Endocrine phenotypes, such as circulating hormone concentrations and sensitivity of endocrine responses, could underlie aspects of ecology, life history, and behaviour that influence organisms’ ability to cope with the challenges of urban habitats. However, to date, comparisons of endocrine phenotypes across urban and non-urban populations within species have revealed no consistent patterns, suggesting that individual and population-level responses to urbanization are complex and likely largely driven by plastic shifts. Here, we investigated the degree to which evolved variation in endocrine phenotypes among species predicts, and potentially contributes to, among-species variation in urban tolerance using a broad analysis of the association between circulating concentrations of baseline corticosterone, stress-induced corticosterone, and testosterone and estimates of urban occurrence for bird species from across the globe. Our results reveal context-dependent links between circulating glucocorticoids and urban tolerance, and lower testosterone concentrations in females from urban-tolerant species, relative to urban-avoidant species. These findings suggest there are multiple strategies for tolerating urban habitats, and indicate that other aspects of the endocrine phenotype, such as the ability to appropriately attenuate responses to urban challenges, might be more important for success in cities. This study provides the first ever among-species comparison of endocrine phenotypes across bird species that differ in their tolerance of urban habitat, offering novel insight into how evolved differences in endocrine traits may impact species’ ability to cope with ongoing urbanization. As the human population expands and many of the world’s natural habitats continue to be developed into urban environments, this knowledge will be crucial in understanding how wildlife will cope with our changing world.
MSc Candidate, diCenzo Lab
Electrifying the Green Economy: Microbial Manufacture of PHB Bioplastic from CO2-derived Formate
Reducing global carbon expenditure requires a dedication to innovation and problem-solving at every level, including a rapid divestment from fossil-based fuels and materials. Fossil carbon-based chemical feedstocks, whose production accounts for 14% of all oil and 8% of all gas demand worldwide, can thus be replaced by carbon-sequestering alternatives that are microbially converted into value-added products. In this work, we aimed to develop such an electro-biohybrid system for the conversion of CO2 to the fully compostable bioplastic, polyhydroxybutyrate (PHB). This system involves the electrochemical reduction of CO2 to formate, which would serve as a feedstock for a PHB-producing microbe. For the microbe, we chose Sinorhizobium meliloti due to its natural ability to grow on a wide range of carbon substrates including formate, its genetic tractability, and its ability to naturally synthesize valuable bioproducts such as PHB. Initial tests revealed that although S. meliloti can use formate as a carbon source, formate concentrations above 20 mM are toxic and inhibit the growth of S. meliloti. There was no significant difference in the growth of S. meliloti when provided 20 mM of commercially available formate compared to electrochemically generated formate, confirming that the electrochemical process did not generate toxic byproducts that would inhibit growth. In ongoing work, we are testing whether S. meliloti accumulates PHB during growth with formate as the sole carbon source. In an effort to increase PHB yield, we are using a S. meliloti mutant lacking the PHB depolymerase gene, which was observed to accumulate more PHB than the wild type in both nitrogen-limiting and nitrogen-excess conditions. Overall, this work contributes to the development of a CO2-to-bioproduct pipeline that might one day displace fossil carbon and transform the petrochemical industry from a carbon-intensive to a carbon neutral operation.
Dr. Richard Feldman, Wildlife Landscape Ecologist
Ontario Ministry of Northern Development, Mines, Natural Resources, and Forestry
My pandemic year birding an urban tropical forest and reflections on seven years in the Yucatan Peninsula
During the pandemic years of 2020 and 2021, I had the good fortune to be able to conduct weekly bird surveys in a local tropical forest fragment in Merida, Yucatan, Mexico. While most of the urban bird assemblage changed little through the year, every visit still brought surprises as non-urban birds still sometimes wandered into the middle of the city. While birding, I could reflect on the research my students and I have conducted in the Yucatan, attempting to understand how communities change across the Peninsula and across seasons. For example, we have found that, during migration, migratory bird species richness is decoupled from local habitat productivity and individual habitat use is unrelated to local resource availability. However, during winter, species redistribute themselves to match productivity gradients. For the talk, I hope you can explore with me how ecological patterns in a region shaped by spatial and temporal variation in precipitation differ from regions shaped by temperature and get to know a place where some Ontario birds spend the winter.
Bio: Richard is currently a Wildlife Landscape Ecologist with the Ontario Ministry of Northern Development, Mines, Natural Resources, and Forestry in Peterborough, Ontario. He has only just started the position after having spent seven years as a research scientist in the Yucatan Center for Scientific Research in Merida, Yucatan, Mexico. He is an alumnus of Queen’s, having graduated in Biology in 1999. He then went on to complete a Master’s in Forest Science at the University of British Columbia, a PhD at McGill, and post-docs at Trent and the University of Massachusetts Amherst. His main research interest is understanding how the response of species to fine-scale environmental variation depends on broader spatial and temporal gradients, such as latitude and seasons. He uses concepts and tools from landscape genetics, behavioural ecology, community ecology, and macroecology.
MSc Candidate, Bendena Lab
Investigating the role of neuropeptide receptor 14 (NPR-14) in Caenorhabditis elegans sleep
Narcolepsy is a sleep disorder characterized by chronic fatigue and episodes of cataplexy. Through studies in human and animal models, a causative link has been revealed between narcolepsy and decreased orexin signaling. In the model organism Caenorhabditis elegans,a G-protein coupled receptor called neuropeptide receptor 14 (NPR-14) has been identified as a potential ortholog to the human orexin receptor-2 (OX2R). Previous phenotypic analyses of npr-14 knockout strains revealed a marked reduction in adult locomotion and mechanosensory stimulation compared to wildtype strains. This narcoleptic-like phenotype observed in npr-14 knockouts, along with the proposed orthologous relationship to OX2R, suggests that npr-14 is involved in the regulation of sleep in C. elegans. C. elegans displays two distinct sleep pathways: the developmentally timed sleep (DTS) pathway, and the stress induced sleep (SIS) pathway. The objective of my thesis research is to elucidate the role of npr-14 in the DTS and/or SIS pathways. This will be achieved by observing DTS and SIS behaviour in npr-14 knockout worms alone and in combination with known regulators of either pathway. Results of this research may uncover epistatic interactions between NPR-14 and components of DTS/SIS, therefore suggesting its potential position within either pathway. Successful characterization of npr-14’s role in C. elegans sleep may provide a model system in which the pathology of narcolepsy and other fatigue-presenting conditions may be explored.
MSc Candidate, Monaghan Lab
E3Ks: Conserved multi-taskers
Investigating the role of a family of multi-functional enzymes in Arabidopsis thaliana
Phosphorylation and ubiquitination are two of the most ubiquitous protein modifications in cells. While phosphorylation is catalyzed by protein kinases, ubiquitination is catalyzed by three subsequent enzymes. In plant cells, there is a proven interplay between protein kinases and E3 ubiquitin ligases, the final enzyme of the ubiquitination series. Generally, protein kinases and E3 ligases are two separate proteins coded by two separate genes. I am interested in a group of unique proteins that contain both kinase and E3 ligase domains in a single protein, hence named ‘E3Ks’. In my study, I focused on understanding the molecular evolution, biochemical and biological functions of this fascinating group of proteins in the model plant Arabidopsis thaliana.
Dr. Steven Kembel
Université du Québec a Montréal
Life on leaves : what are the drivers of phyllosphere bacterial diversity?
The aerial surfaces of plants including leaves (the “phyllosphere”) are an important habitat for bacteria. Leaf-associated bacteria are extremely diverse and perform important ecological functions with implications for host plant health and ecology as well as for ecosystem function, but our understanding of the ecological and evolutionary drivers of plant-microbe associations on leaves has been relatively limited. Here I present two case studies of the factors that drive plant-bacteria associations across spatial and phylogenetic scales. In the first case study, we studied populations of the plant-associated genus Methylobacterium living on tree leaves in Quebec forests. Phylogenetically-informed ecological analyses of Methylobacterium diversity demonstrated the importance of environmental factors including temperature for driving dynamics of these populations in space and time. We observed consistent successional patterns of Methylobacterium on leaves throughout the growing season, which were explained by the evolution of ecological strategies within the genus. In the second case study at broader spatial and phylogenetic scales, we studied how the drivers of plant-bacterial associations on leaves varied along a latitidunal gradient from temperate to tropical forests in China. We found that factors including host plant attributes, the abiotic environment, space, and plant neighborhood effects jointly explained most of the variation in phyllosphere bacterial diversity and biogeography, but the importance of plant host attributes increased strongly with increasing latitude. Most phyllosphere bacteria were host-specialized, and the degree of specificity varied with latitude and host plant rarity. Taken together these results suggest avenues for predicting and managing plant microbiomes under global change.
Dr. Steven Kembel is Professor of Biological Sciences and Canada Research Chair in Plant Microbiomes at the Université du Quebec à Montréal (UQAM). Dr. Kembel completed his B.Sc. in Botany at the University of Manitoba, a M.Sc. and Ph.D. in Biology at the University of Alberta, followed by postdoctoral fellowships at the University of California, Berkeley and the University of Oregon. His research program focuses on understanding the ecological and evolutionary processes that govern patterns of microbial diversity, and on the effects of microbes on host ecology and function in plant and animal microbiomes.
MSc Candidate, SMOL LAB
Assessing lake ecosystem recovery from acidification and responses to emerging environmental stressors in a suite of lakes from Sudbury, Ontario, Canada
Mining and smelting activities have strongly influenced the Sudbury (Ontario, Canada) region since the late 19th century, leading to acidification and metal contamination in many local ecosystems. Regulations on restricting acidic emissions were enacted in the 1970s, after which a considerable volume of paleolimnological work was completed to study the impacts of acidification and metal deposition on Sudbury-region lakes and their subsequent biological recovery. Twenty years after the last regional diatom-based assessment, many lakes have undergone large changes in limnological variables, including increases in pH and dissolved organic carbon concentrations, as well as decreases in metal concentrations. Additionally, these lakes are under the potential impacts of newly emerging environmental stressors such as climate warming and road salt contamination. Here, I revisited a suite of Sudbury-region lakes (n=80) by examining their current water chemistry and diatom assemblages preserved in surface sediments. A canonical correspondence analysis was used to assess the relationships between diatom assemblage composition and environmental variables. Although the pH gradient in my study lakes is shorter than earlier calibration studies conducted in this region by more than one pH unit, lakewater pH was still identified as the strongest environmental variable shaping diatom distributions and so was used to construct a robust inference model (R2boot=0.73; RMSEP=0.32). By assessing ecological changes experienced by Sudbury-region lakes over the past few decades, I identified two major trends: an overall increase in diatom-inferred pH, and a rise in the relative abundance of planktonic taxa. Lastly, several down-core analyses were conducted to assess detailed ecological changes of Sudbury-region lakes over the past ~150 years. Although some lakes are tracking recovery in diatom assemblages, other lakes have less clear ecosystem trajectories.
MSc Candidate, Snedden Lab
Investigating the interaction of Arabidopsis calmodulin-like (CML) proteins with calmodulin-binding transcription activators (CAMTAs)
Understanding the myriad ways that organisms detect and interpret information from their environment is an ongoing goal of cell biology. A common theme among eukaryotic cells is the use of calcium ions (Ca2+) as second messengers to coordinate responses during information processing. In plants, Ca2+ signals are evoked during responses to abiotic and biotic stresses and during development. These signals are detected by Ca2+-binding proteins (sensors), such as the evolutionarily-conserved protein calmodulin (CaM), which regulates various downstream target proteins to organize signal transduction pathways. In addition to CaM, plants have evolved a remarkable array of CaM-like proteins (CMLs) that are not found in animals. The genetic model, Arabidopsis, has seven CaMs and 50 CMLs, most of which remain unstudied. Why do plants need so many of these Ca2+ sensors? What are their downstream targets? How do they contribute to Ca2+ signaling during stimulus response? Research on CML structure/function is needed to develop a broader understanding of how plants respond to environmental cues. Recently, our lab has been exploring the roles of two paralogs, CML13,14, which possess unique biochemical properties among CaMs and CMLs. To help uncover CML13,14 function, we screened a yeast 2-hybrid library for putative target proteins and discovered 3 families of functionally unrelated proteins that share a common structural feature; tandem IQ domains. IQs are unique CaM binding domains that have been mostly studied in the myosin motor proteins of animals. In addition to myosins, we identified several CaM-binding transcription activators (CAMTAs) as putative CML13,14 targets. CAMTAs possess multiple IQ domains and are important transcription factors in plants that regulate gene expression during abiotic and biotic stresses such as cold, drought, salt stress, pathogen attack, and herbivory. I will present data from my MSc project where I explored the question; are Arabidopsis CAMTAs targets of CML13,14? My project focused mainly on assessing the properties of CML13/14-CAMTA binding, using both in planta and in vitro methods to assess whether the interaction may be physiologically relevant. Collectively, my data supports the hypothesis that CAMTAs and CMLs interact in plants and suggests a novel mechanism through which Ca2+ signals regulate gene expression during stress response.
Dr. Emilie Snell-Rood
University of Minnesota
Responses to novel and changing environments: predicting how plasticity may interact with evolutionary change
Why do some organisms thrive in novel and changing environments while others do not? While both plastic and evolutionary changes may allow populations to survive and diversify in new conditions, it is not always clear how these processes interact. In this talk, I walk through how a deeper understanding of the underlying mechanism of plasticity has implications for thinking about costs, life history tradeoffs, and the precision of a trait match to a new environment. Using examples from behavioral and physiological plasticity in butterflies, and resource variation across butterfly species, I will discuss how a more developmental perspective can help us to move forward in thinking about how plasticity affects evolution in novel environments.
Bio: Emilie Snell-Rood is an Associate Professor of Ecology, Evolution and Behavior at the University of Minnesota. She received her bachelors in biology at the College of William and Mary in Virginia and a PhD in Ecology and Evolutionary Biology from University of Arizona. She did a postdoc at Indiana University before starting her position at Minnesota in 2011. As she will discuss today, Emilie is interested in why organisms vary in developmental flexibility and what this means for survival in new environments. She has worked on a range of systems including butterflies, dung beetles, birds, and mammals. In the educational space, she is also developing materials for collaborative interactions between biology and bio-inspired design.
Dr. Landon Getz, Dalhousie University
Editing Nature: Genetically Modified Mosquitoes and a Case for Slow Science
Mosquito-borne diseases - malaria, dengue fever, zika, and others - are a significant burden on global health and economies. As such, a variety of interventions that target and reduce mosquito populations have been developed and used to manage disease transmission and its consequences. The advent of new genetic technologies, like CRISPR/Cas9, provide innovative solutions to mosquito control and have shown significant promise in reducing mosquito populations. However, these interventions require the release of genetically-modified mosquitoes into shared spaces and carry significant uncertainty and risk. The promise and peril of these interventions make them an excellent case study for how we do science, and how we ought to do science. Taking a "Slow Science" approach to editing nature can help ensure that it is done safely, ethically, and with the support of the communities involved.
Landon J. Getz, Vanier Scholar and Killam Laureate
Landon Getz is a PhD Candidate at Dalhousie University in the Department of Microbiology and Immunology. His research investigates the environmental survival mechanisms of the marine prokaryote Vibrio parahaemolyticus and how these mechanisms to can lead to virulence in human hosts. Landon is a member of the Chief Science Advisor's Youth Council and has a keen interest in science's interconnectedness with politics, policy, and ethics. As such, Landon has explored ethical and justice issues related to gene-editing in humans, as well as the social, environmental, and ethical issues associated with gene-editing in insects (primarily mosquitoes).
MSc Candidate, Eckert lab
A shift from sexual to asexual reproduction in a wetland plant: implications for range edge dynamics
All species have limits to their geographic distributions, and these limits are thought to reflect a failure of adaptation to conditions beyond the range. The adaptive capacity of populations at range limits could be strongly influenced by the amount and distribution of genetic variation, which in turn is strongly affected by variability in reproductive system, particularly in plants which exhibit diverse reproductive modes. Plants can reproduce sexually, either through outcrossing (exchanging pollen with other individuals) or self-fertilization. Many plants have the capacity for some form of asexual reproduction as well, by producing parthenogenic seeds or clonal reproduction via vegetative propagation. Sexual and asexual reproduction have different ecological requirements, meaning that a species with both methods of reproduction can have separate sexual and asexual niches. In some species, the sexual niche is narrower than the asexual niche, thus shifts to asexuality might allow these species to thrive in environments where sexual reproduction is inhibited. Decodon verticillatus is a wetland plant that reproduces sexually through most of its range and exhibits a shift to asexual clonal reproduction at the northern range margin. For my master’s research I am investigating the evolutionary causes and consequences of this shift to asexuality, and the implications for range edge dynamics in Decodon verticillatus using a transcriptomic analysis of RNA-seq data. I found that the range-edge populations show genetic signatures of long-term asexuality, such as increased heterozygosity and a breakdown of isolation by distance. This suggests that the asexual populations are long-lived and well-established, and that shifting to asexuality may have allowed range expansion beyond the sexual niche of D. verticillatus. Understanding the factors that influence range limits and range expansion is becoming increasingly important to better anticipate the capacity of species to adapt, and potentially shift their ranges in response to anthropogenic environmental changes.
Lee Marie Raytek
MSc Candidate, Snedden Lab & Plaxton Lab
In vivo hyperphosphorylation of the Ca2+/calmodulin-dependent glutamate decarboxylase isozyme AtGAD1 in phosphate-resupplied Arabidopsis thaliana
Inorganic phosphate (Pi) has a crucial role in plant development, yet it is often the most limiting macronutrient of many soils. Pi starved (-Pi) plants elicit a Pi starvation response that alters gene expression and metabolism to enhance their efficiency of Pi acquisition and use. This research field is enabling the development of innovative strategies for engineering Pi-efficient crops, urgently needed to reduce inputs of unsustainable and non-renewable Pi fertilizers for long-term global food security and ecosystem preservation. Our recent phosphoproteomic study revealed that the glutamate decarboxylase AtGAD1 became in vivo phosphorylated at multiple serine residues (located near its N-terminus) 48 h following resupply of 2 mM Pi to -Pi cell cultures of the model plant Arabidopsis thaliana. AtGAD1 is a root-specific, cytosolic GAD isozyme. GADs catalyze the first committed step of the 4-aminobutyrate (GABA) shunt by decarboxylating glutamate into GABA, an important yet enigmatic ‘stress’ metabolite and apparent signal molecule. GAD is the only enzyme of central plant metabolism known to be activated by Ca2+/calmodulin-binding; however the functions or mechanisms of plant GAD phosphorylation have not been studied, although similar N-terminal hyperphosphorylation of AtGAD1 and its orthologs has been described in numerous studies of the phosphoproteome of Arabidopsis and other plants. My thesis research seeks to test two hypotheses: (i) phosphorylation inhibits AtGAD1 activity, and/or (ii) phosphorylation affects AtGAD1’s subcellular localization. This involves comparing the physical and kinetic properties of FPLC-purified, native phospho- versus dephospho-AtGAD1, and molecular cloning of mCherry-AtGAD1 fusion constructs needed to visualize the enzyme’s location in –Pi versus Pi-resupplied cells. Assessing the interplay between Pi nutrition and AtGAD1 phosphorylation will contribute to elucidating the physiological roles of GABA and the GABA shunt under Pi stress and potentially other stresses.
Dr. Eric Capo
Institut de Ciencies del Mar, Spanish National Research Council
Merging two worlds: application of molecular ecology tools in paleolimnology to study the long-term changes in aquatic microbial communities
Historical deposits of sedimentary DNA are a promising target for molecular tools with potential to inform about long-term changes in aquatic microbiome (i.e., bacteria, archaea protists, fungi, viruses) and how microorganisms are controlled by viral infection, pathogens, and larger predators (e.g., zooplankton and fish). As sedimentary DNA archives can encompass timescales that span decades to hundreds of thousands of years, they complement and enhance contemporary data derived from water monitoring. The data from such historical monitoring is integrative and enable ad hoc assessment of biological responses to past environmental and more recent anthropogenic perturbations. Over the last decade, studies using sedimentary DNA metabarcoding successfully reconstruct temporal changes in microbial communities, including cyanobacteria and microbial eukaryotes. I present here an overview of this research field, some of my ongoing research projects on lakes Biwa (Japan), Ekoln (Sweden) and the Black Sea, and reveal the potential to answer questions that can only be provided when including sedimentary DNA for the reconstruction of long-term temporal changes in aquatic microbial communities.
Bio: Eric Capo has a PhD in molecular paleoecology with skills in molecular biology, data analysis and aquatic microbial ecology. His interests lie in the ecology of aquatic systems (freshwater and marine systems), the temporal dynamics of microbial communities and their functional responses to environmental perturbations (climate, eutrophication, mercury pollution). He is the founder and coordinator of the sedaDNA scientific society, an international network of sedaDNA research and the co-founder of Mersorcium, a consortium about microbial Hg-cycling in the environment.
MSc Candidate, Tufts lab
Acoustic Telemetry Provides New Insights on the Ecology of Smallmouth Bass in Eastern Lake Ontario
Smallmouth Bass (Micropterus dolomieu) are an integral freshwater predator with a wide
distribution in North America. Our understanding of Smallmouth Bass ecology is extensive but
primarily based on research from smaller inland lakes, rivers, and reservoirs. Smallmouth Bass
are native to the Great Lakes, but much less is known about their ecology in these large
waterbodies. In Lake Ontario, there is an urgent need for additional research on this species due
to suggested changes in their population status by provincial and state agencies. Smallmouth
Bass in the Southern Great Lakes have also recently experienced large increases in angling
pressure due to the region's growing popularity of bass tournaments. The main objective of the
present study was to examine whether a novel acoustic telemetry approach could be used to
obtain new information on the ecology of Smallmouth Bass in the eastern basin of Lake Ontario.
This study showed that it was possible to continuously monitor an experimental group of
Smallmouth Bass using acoustic telemetry from September 2020 to October 2021. These results
provide new evidence that Smallmouth Bass exhibit local residency in large lake ecosystems to a
much greater degree than previously understood. Observations from acoustic transmitters also
showed changes in the seasonal ecology of resident fish. Wintering areas were not far from
summer home ranges, but Smallmouth Bass occupied deeper depths and reduced their activity
during the winter. Some of these results have important implications for assessing and managing
Smallmouth Bass populations in the Great Lakes.
Marco Lee, PhD Student
Nelson and Moyes Lab
Metabolic Phenotype of Daphnia under Hypoxia: Macroevolution, Microevolution, and Phenotypic Plasticity
Hypoxia is a stressor that influences animal function from ecology to molecular biology. Animals cope with hypoxia through strategies that improve oxygen delivery and anaerobic energy metabolism. Daphnia is a freshwater crustacean that can upregulate hemoglobin (Hb) in response to hypoxia, imparting a red color. We combine multiple field surveys across season with a common garden experiment to evaluate changes in the metabolic phenotype of Daphnia in relation to environmental hypoxia. We observed seasonal changes in the metabolic phenotype that differed between red and pale animals. Hb was upregulated early in the season in Daphnia in hypoxic lakes, and a relationship between Hb and lactate dehydrogenase, a key enzyme in anaerobic metabolism, only emerged later in the season in a lake-specific temporal pattern. To evaluate whether these differences were due to specific lake environments or microevolutionary differences, we ran a common garden experiment using six isofemale lines from each of four lakes. We found a strong response to 18 h hypoxia exposure in the expression of both Hb and lactate dehydrogenase. Unexpectedly, other glycolytic enzymes, pyruvate kinase and enolase, were not upregulated under hypoxia. This contrasts observations in vertebrate models, as hypoxia often triggers a suite of responses controlled by the master transcriptional regulator hypoxia-inducible factor. Overall, the combination of lab and field studies suggest that the metabolic phenotype of the animal is dictated by both microevolutionary differences (within and between lakes) as well as the spatial and temporal environmental heterogeneity of the lakes. In addition, hypoxic responses in Daphnia may be regulated by serveral independent pathways, highlighting the importance of studying animal models with distinct ecology to understand the evolution of hypoxia-driven phenotypic remodeling.