In many plant species, FLOWERING LOCUS T and related proteins are the mobile signal that communicates information on photoperiod from the leaves to the shoots, where the transition to flowering is realized. FT expression is tightly controlled at the transcriptional level so that it is restricted to leaves, occurs only in appropriate photoperiods, and integrates ambient temperature and developmental cues, as well as information on biotic and abiotic stress. We previously established that FT transcription in the model plant Arabidopsis thaliana requires proximal promoter cis-elements and a distal enhancer, both evolutionary conserved among Brassicacea species. In addition, FT transcription is blocked prior vernalization in biannual accessions and vernalization-dependency of FT is controlled through a CArG-box located in the first intron that binds the transcriptional repressor FLOWERING LOCUS C (FLC). Chromatin-mediated repression by the Polycomb Group (PcG) pathway is required for photoperiod-dependent FT regulation and participates in FT expression level modulation in response to other cues.In this project, I propose to explore the available sequence data from the 1001 genome project in Arabidopsis to evaluate how often changes in regulatory cis-elements at FT have occurred and how these translate into an adaptive value. Allele-specific FT expression pattern will be measured in F1 hybrids of different accessions in response to varying environmental conditions. FT alleles that show cis-regulatory variation will be further analyzed to pinpoint the causal regulatory changes and study their effect in more detail. The allotetrapolyploid species Brassica napus is a hybrid of two Brassiceae species belonging to the A- and C-type genome, which are in turn mesopolyploid due to a genome triplication that occurred ca. 10x106 years ago. We will determine allele-specific expression of FT paralogs from both genomes of a collection of B. napus accessions. The plants will be grown in the field in changing environmental conditions to maximize the chance to detect expression variation of the paralogs. We will compare the contribution of the founder genomes to the regulation of flowering time and asses variation in this contribution. A particular focus will be to study the impact of chromatin-mediated repression on allele selection in B. napus.
In my project I aim at a better understanding of the evolution of malacostracan crustaceans, which includes very different groups such as mantis shrimps, krill and lobsters. Previous studies on Malacostraca, on extant as well as on fossil representatives, focussed on adult morphology.In contrast to such approaches, I will apply a Palaeo-Evo-Devo approach to shed new light on the evolution of Malacostraca. Palaeo-Evo-Devo uses data of different developmental stages of fossil malacostracan crustaceans, such as larval and juvenile stages. With this approach I aim at bridging morphological gaps between the different diverse lineages of modern malacostracans by providing new insights into the character evolution in these lineages.An extensive number of larval and juvenile malacostracans is present in the fossil record, but which have only scarcely been studied. The backbone of this project will be on malacostracans from the Solnhofen Lithographic Limestones (ca. 150 million years old), which are especially well preserved and exhibit minute details. During previous studies, I developed new documentation methods for tiny fossils from these deposits, e.g., fluorescence composite microscopy, and also discovered the first fossil mantis shrimp larvae. For malcostracan groups that do not occur in Solnhofen, I will investigate fossils from other lagerstätten, e.g., Mazon Creek and Bear Gulch (USA), or Montceaules- Mines and La-Voulte-sur-Rhône (France). The main groups in focus are mantis shrimps and certain other shrimps (e.g., mysids, caridoids), as well as the bottom-living ten-footed crustaceans (reptantians). Examples for studied structures are leg details, including the feeding apparatus, but also eyes. The results will contribute to the reconstruction of 3D computer models.The data collected in this project will be used for evaluating the relationships within Malacostraca, but mainly for providing plausible evolutionary scenarios, how the modern malacostracan diversity evolved. With the Palaeo-Evo-Devo approach, I am also able to detect shifts in developmental timing, called heterochrony, which is interpreted as one of the major driving forces of evolution. Finally, the reconstructed evolutionary patterns can be compared between the different lineages for convergencies. These comparisons might help to explain the convergent adaptation to similar ecological niches in different malacostracan groups, e.g., life in the deep sea, life on the sea bottom, evolution of metamorphosis or of predatory larvae.As the project requires the investigation of a large number of specimens in different groups, I will assign distinct sub-projects to three doctoral researchers. The results of this project will not only be published in peer-reviewed journals, but will also be presented to the non-scientific public, e.g., during fossil fairs or museum exhibitions with 3D models engraved in glass blocks.
Lichen conservation biology is often faced with widely distributed, but strongly fragmented taxa. If in a global Red List assessment such a taxon is treated as one single unit, one large and stable population may result in a low conservation status of the global population, despite the fact that most populations face a strong decline. In case the global population of a taxon is subdivided into evolutionary significant units (ESU), an individual Red List status might be assigned to each ESU. However, the complex life cycles and long generation times make it very difficult to identify ESU for lichens if ecological differentiation is the crucial criterion for their distinction. As an alternative approach to delimit ESU, genetic differentiation of regional populations has been suggested. Recent developments of molecular markers demonstrated considerable levels of regional genetic differentiation among populations within species and during our first Scopes project we found high levels of genetic differentiation within L. pulmonaria between biogeographic regions in Russia. We identified a broad suture zone of two different evolutionary lineages in the Ural Mountains. The western lineage, as identified by ITS sequences is widely distributed in Africa and Western, Northern and Central Europe. The eastern lineage was found so far in Russia East of the Urals and in North America. Concerning the differentiation within the two ITS types it is likely that these genetically differentiated populations of L. pulmonaria developed independently over considerable evolutionary periods rather than became demographically autonomous through recent isolation, e.g. during anthropogenic deforestation. In this project we will sample additional populations along this suture zone, as well as east and west of it to study possible gene flow between the two distinct evolutionary lineages. In order to test if the genetic differentiation found in regional populations parallel ecological adaptation, we had established a provenance clone test during our first Scopes project. We expect that during the coming three years the growth of the transplants will have reached an optimal level, which will then allow to test if survival and growth rate, diaspore production and degree of parasite attack differ between the provenances from the Carpathians, the Ural Mountains, The Komi Republic and Sakhalin. A differentiation between the studied L. pulmonaria population into regional ecotypes would have a significant impact on the conservation status of this species, because its global population could be subdivided into regional ESU.
Background The species environmental niche consists of the biotic and abiotic conditions necessary for long-term persistence. This concept occupies a central place in the ecological theories of competition, limiting ecological similarity, and species distribution. The niche is also important in determining how species respond to ongoing climate change. Species with narrow niches occur in the few geographic locations that offer acceptable conditions. When these species have limited capacity for dispersal, and/or have been isolated by human activity, climate change may force upon species the alternatives of rapid adaptation (via response to natural selection) or extinction. We focus on the niches of species in the Restionaceae, largely endemic to South Africa. The Goals We seek to understand how the species niche has evolved and how the capacity for niche change might impact future patterns of species diversity in the face of ongoing climate change. Gaining an understanding of these niche dynamics entails understanding how species niches differ currently and how these differences evolved. We need to understand how rates of evolution in groups of related species change in time. To understand how niche evolution translates into changes in biodiversity, we need to understand how ecological similarities among species, represented by species evolutionary relationships, influence the composition of ecological communities. The Approach We combine the approaches of evolutionary theory, molecular systematics, and ecology. The approach is interdisciplinary in that activities in these areas produce results that are used to support subsequent activities in other disciplines. Notably, DNA sequence data provide the raw material for developing hypotheses of evolutionary relationships. Data on species occurrences and climate allow us to model the species niche. We combine information on evolutionary relationships, ecological characteristics, and species composition in communities to determine how evolutionary relationships influence the assembly of communities. The Significance of the Project This project develops a framework for evaluating how rapid evolution might contribute to species responses to climate change. With this framework it will be possible to evaluate the potential for evolutionary response to climate change in large groups, potentially hundreds, of related species. We will develop more informed projections of the impacts of ongoing climate change by combining ecological data, understanding of evolutionary relationships and rates, and projections of future climates.
The project will use analysis of long-term data, resurrection ecology and modeling to investigate the ecological and evolutionary response of an aquatic key herbivore, Daphnia, to environmental change. In addition, the results obtained will enable to estimate the consequences of the evolutionary response of Daphnia for its population dynamics, persistence and consequently, overall ecosystem dynamics. The project will analyze in detail the response of Daphnia, its food, competitors and predators to oligo-trophication in a model ecosystem, i.e., Lake Constance and additionally variability in Daphnia population dynamics in several of the best studied lakes of the world. Historical field samples from Lake Constance will be re-analyzed to study the phenotypic life history and morphological responses of Daphnia to oligo-trophication. Using resurrection ecology we will analyze the evolutionary response of Daphnia galeata life history parameters to oligo-trophication - with special emphasis on its investment into sexual reproduction/production of resting eggs as well as life history plasticity in response to invertebrate predators and declining food levels. These analyses (in combination with model simulations) will provide key data for understanding the role of Daphnia life cycle strategy (overwintering in the plankton or in resting eggs) for Daphnia persistence in permanent lakes, for the interpretation of Daphnia resting egg banks, and the evolution of the genetic variances and co-variances of life history parameters.
Plants grow in complex ecological networks, and show finely tuned adaptations to attact mutualists such as pollinators, and deter enemies such as herbivores. To do so, plants use volatile signals (BVOCs biogenic volatile organic compounds) that are emitted from vegetative (e.g. leaves) or flowers. Leaf volatiles are often thought to be involved in defense, whereas floral volatiles are traditionally interpreted as attractants for pollinators. However, recent studies have shown that floral scent may as well be involved in defending reproductive structures against antagonists. This can be achieved by emitting repellent compounds from flowers. The obvious need of plants to attract pollinators to flowers on the one hand, and to defend flowers on the other hand, puts them into a dilemma. Such signaling dilemma or trade-offs suggest optimal fitness outcomes may be a compromise between attraction (pollinators, parasitoids) and deterrence (herbivores); a key factor selecting for differential signaling may thus be the abundance and species identity of these interacting organisms in a given habitat. Signaling conflicts may also differ among pollination systems, e.g. when pollinators are also herbivores (moth pollination), attracting an herbivore is unavoidable for pollination. Under strong herbivore attack, however, plants may even switch pollination system by changing BVOC signaling to escape the herbivore pressure. This particular project will focus on ecological and evolutionary aspects of flower signaling to pollinators and the impact of novel herbivores on this mutualism. Up till now, we know surprisingly little about how herbivore induced changes in floral volatiles (HICFV) and the resulting change in flower attractiveness to pollinators. This IP will investigate HICFV after attack of established and novel herbivores (both on shoots and roots) and its molecular basis and variability. Lastly, natural selection on HICFV will be studied in populations with and without invasive herbivores, to asses their impact on the evolution of this key plant signaling trait and model future evolutionary change.
Niche-based models (NBMs) are increasingly used to predict the geographical extent of invasion of alien species using empirical statistical correlations describing the presence of a species as a function of environmental variables. The classic approach is to calibrate the model in the native species range and to project the model in the new invaded range to predict suitable areas for the establishment of the species, assuming that ecological requirement of the species is conserved. However, recent studies demonstrated that climatic niche shifts can occur in the invaded range enabling some species to invade new and unpredictable habitats. While NBMs are useful tools to predict areas of introduction, they may fail to predict the full extent of species invasions. NBM approaches usually treats invasive species as homogeneous and immutable entities. However, recent studies in evolutionary biology have shown that invasive species in the new range could experience hybridization, evolution of increased competitive ability or new phenotypic adaptations as a result of the absence of natural enemies. It is thus imperative to move beyond treating invasive species as genetic black boxes in mitigation and management strategies. During this post doc, I will analyze the distribution of Spotted Knapweed (Centaurea maculosa) at the genetic lineage level using jointly niche-based models and population phylogeny approaches. 75 native and 37 introduced populations sequenced for 2 cpDNA markers will be investigated to identify sources of introduction and cryptic boundaries, such as breaks in the gene flow across populations, or secondary contact among previously isolated populations. The relationship between genetic architecture and ecological factors which determine the success of invasion processes will ultimately be used to trace back invasion routes of Spotted Knapweed in North America.
For effective crop improvement, breeders must be able to select on relevant phenotypic traits without compromising yield. This project proposes to investigate the evolutionary consequences of flowering time modifications on a second trait of major importance for plant breeding: immunity. This will have implications both for understanding cross-talks between flowering time and defense network and for developing efficient breeding strategies. There is clear evidence that plant maturity influences levels and effectiveness of defense. Theoretical models actually predict that changes in life-history can modulate the balance between costs and benefits of immunity. Simultaneously, actors of the immune system have often been observed to alter flowering time. Two alternative and possibly complementary hypotheses can explain this link: genetic constraints due to the pleiotropic action of players in either systems, or co-evolution, if flowering-time changes modulate the cost-benefit balance of immunity. We will conduct field assays in Arabidopsis thaliana, using constructed lines as well as recombinant inbred lines and natural accessions, to differentiate the action of the two explanatory hypotheses. Using transcriptome analyses, we will identify defense genes associating with flowering time modification (f-t-a defense genes). We will quantify their expression along the assay and test whether it varies with both flowering time and fitness. We will further test whether flowering time and immunity interact to determine yield in tomato and potato.
Enzyme der Peroxidase-Cyclooxygenase Superfamilie katalysieren biochemische Reaktionen, die in unzähligen biologischen Prozessen eine wichtige Rolle spielen, z.B. bei der unspezifischen Immunabwehr, der Synthese der Schilddrüsenhormone oder der Bildung und Modifizierung der extrazellulären Matrix. Sie sind zudem auch bei der Pathogenese von chronischen entzündlichen Erkrankungen beteiligt. In der Subfamilie 2 dieser Superfamilie findet man Multidomänen-Oxidoreduktasen, sog. Peroxidasine (Pxds). Hierbei handelt es sich um glykosylierte und sekretierte Häm-Peroxidasen, die zusätzlich zur katalytischen Domäne sog. Leucin-reiche Wiederholungssequenzen, Immunoglobulin C-ähnliche Domänen sowie von Willebrandfaktor C enthalten. Diese Strukturmotive finden sich in vielen extrazellulären Molekülen, die mit anderen Proteinen in Wechselwirkung treten. Ursprünglich wurde Peroxidasin in Basalmembranen von Drosophila entdeckt. Spätere Arbeiten zeigten, dass diese Enzyme auch in Wirbeltieren vorkommen und eine Rolle bei der unspezifischen Immunabwehr, der Gewebsbildung, Ausbreitung von Tumoren und oxidativen Prozessen eine Rolle spielen. Kürzlich wurde gezeigt, dass dieses Metallprotein mit Hilfe von Hypohalogeniten im Kollegen IV für die Bildung von kovalenten Kohlenstoff-Stickstoffbindungen verantwortlich ist, ein Prozess, der sowohl bei der Gewebsbildung als auch bei zahlreichen Kranksheitsbildern eine wichtige Rolle spielt. Trotz der physiologischen Bedeutung dieser neuen Proteinfamilie ist das biochemische Wissen sehr bescheiden. In diesem Projekt sollen daher, basierend auf umfangreichen phylogenetischen Voranalysen und der bereits erfolgreich durchgeführten rekombinanten Produktion von humanem Peroxidasin 1 in tierischen Zellkulturen, die Struktur-Funktionsbeziehungen von vier Peroxidasinen unterschiedlicher Entwicklungsstufe und Sequenz analysiert werden: Peroxidasin 1 von Caenorhabditis elegans, Pxd von Drosophila melanogaster als auch die beiden humanen Peroxidasine 1 & 2. Basierend auf der rekombinanten Produktion der vier Modell-Proteine in voller Kettenlänge bzw. von verkürzten Varianten unterschiedlicher Domänenzusammensetzung werden umfangreiche bio-chemische/biophysikalische Analysen durchgeführt: (i) UV-vis-, Fluoreszenz- CD-, Lichtstreuung-, RR- und ESR-Spektroskopie, (ii) Stopped-flow-Spektroskopie und Polarographie, (iii) MS und Röntgenkristallographie, (v) Spektroelektrochemie und (vi) Kalorimetrie. Mit Hilfe dieser Methoden sollen Struktur und Aktivität der Peroxidasine aufgeklärt werden wie z.B. (i) oligomere Struktur und Architektur des aktiven Zentrums, (ii) Interaktion der Domänen und Mechanismen der Proteinentfaltung, (iii) Chemie der prosthetischen Gruppe inklusive Oxidations- und Spinzustände, Häm-Liganden und posttranslationale Modifizierungen, (iv) Spezifität, Zugänglichkeit, und Bindungorte von Substraten als auch chemische Natur der Reaktionsprodukte (v) Chemie, Reaktivität und Relevanz von Redox-Intermediaten und (vi) die Ro
The world is currently experiencing a major biodiversity crisis due to human activities. A primary concern is the on-going and rapid biological consequences of global climate change. Climate change is impacting alpine landscapes at unprecedented rates, with severe impacts on landscape structure and catchment hydrodynamics, as well as temperature regimes of glacial-fed rivers. Most glaciers are expected to be dramatically reduced and many even gone by the year 2100, concomitantly with changes (timing and magnitude) in temperature and precipitation. These environmental changes are predicted to have strong impacts on the persistence and distribution of alpine organisms, their population structure and community assembly, and, ultimately, ecosystem functioning. However, how alpine biodiversity (aquatic macroinvertebrates in our case) will respond to these changes is poorly understood. Most previous studies predict the presence of species based on the distribution of putatively suitable habitats but ignore biotic traits, such as dispersal, and potential eco-evolutionary responses to such changes. Clearly, accurate predictions on species responses require integrative studies incorporating landscape dynamics with eco-evolutionary processes. The primary goal of the proposed research is to empirically test determinants of alpine macroinvertebrate responses to rapid environmental change mediated by glacial recession. Climate-induced glacial retreat is occurring rapidly and in a replicated fashion (i.e. over multiple catchments and continents), which provides a natural experiment for testing determinants of organismal and species diversity responses to climate change in alpine waters. The responses of alpine aquatic macroinvertebrates are highly important because of their known sensitivity (i.e. response rates) to environmental change and their fundamental role in ecosystem functioning. Using an integrative comparative and experimental approach, we will target the following main question: What are the roles of ecological and evolutionary processes in population level responses of macroinvertebrates to environmental change? The study will take advantage of rapid glacial recession (environmental change) to empirically examine spatio-temporal patterns in species distribution in nature, combined with experimental and population genetics approaches. The data generated will be used to explicitly address the role of eco-evolutionary processes (determinants) on population level responses for selected key species. Spatial and temporal variation in species distribution, phenotypic and genetic variation will be quantified for two stream macroinvertebrates (hemimetabolous mayfly Baetis alpinus, holometabolous caddisfly Allogamus uncatus), and measuring landscape features and physico-chemical parameters along longitudinal transects downstream of glaciers and selected side-slope tributaries (as potential stepping stones for dispersal and colonization).
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