Botanik Seminar
Ein gemeinsames Seminar des Lehrstuhls für Systematik, Biodiversität & Evolution der Pflanzen, der Botanischen Staatssammlung München und des Botanischen Gartens München-Nymphenburg
Wann? Mittwochs
- Botanik Seminars um 16:15 Uhr (während des Semesters)
- Mendel/Hybridisierung Seminars um 18:30 Uhr
Wo?
- Präsenz und Streaming: Großer Hörsaal im Botanischen Institut, Menzinger Str. 67, 80638 München.
- Nur Online und Streaming Link: Zoom meeting* Hier klicken Meeting-ID: 931 8542 4499, Passcode: Botany
(*Wenn kein Dialogfeld angezeigt wird, klicken Sie unten auf: Launch Meeting)
Programm
20.04.2022 um 18:30 Uhr und Präsenz: Die Mischung macht’s - Hybride in Natur und Kultur
Prof. Dr. Joachim W. Kadereit, Johannes Gutenberg-Universität Mainz
Der Triumph der Unangepassten: Die Bedeutung von Hybridisierung in der Evolution der Pflanzen
Als Kreuzungsprodukt zwischen an ihre Lebensumstände gut angepassten Arten sind Hybridindividuen nicht gut angepasst. Dennoch sind sie auf unterschiedliche Weise Ausgangspunkt für weitere Evolution. Durch Rückkreuzung mit einer der Elternarten oder Kreuzung untereinander ohne oder mit Verdoppelung der Chromosomenzahl, sind zahlreiche neue Entwicklungslinien mit neuen Merkmalen entstanden. Die dem zugrundeliegenden Prozesse werden im Vortrag von Herrn Prof. Dr. Joachim Kadereit (Johannes Gutenberg-Universität Mainz) dargestellt.
27.04.2022 um 4:15 Uhr und Online: Prof. Dr. Micah Dunthorn. Natural History Museum, University of Oslo, Norway.
Equating OTUs with Species Diversity
Species are fundamental biological units used in ecological and evolutionary analyses. Because protistan diversity is so large and their morphological characters are so small, molecular methodologies are the only way that we can attempt to uncover most protistan species in complex environmental samples. One step in the sequencing-bioinformatics pipeline of molecular methodologies is clustering sequencing reads into operational taxonomic units (OTUs). These OTUs are used in the place of species in downstream analyses. Here I will discuss the underlying assumptions that different clustering methods make in how they handle metabarcoding data. I will then discuss how these differently constructed OTUs may or may not equate with our concepts of species and with the operational criteria that we use to delimitate species in nature.
Host: Prof. Dr. Marc Gottschling
04.05.2022 um 4:15 Uhr und Präsenz: Prof. Dr. Jouko Rikkinen. Finnish Museum of Natural History Luomos, Finland.
Diversity and evolutionary ecology of fungus-growing termites and their fungal symbionts
Many insects establish obligate symbioses with prokaryotic and/or eukaryotic microorganisms. The gut symbionts of termites including both bacteria and protists which allow these insects to feed on dead wood and plant litter. Higher termites (Macrotermitinae, Blattodea) have evolved an additional symbiosis with filamentous fungi. Their fungal symbionts belong to the genus Termitomyces (Lyophyllaceae, Basidiomycota), which only includes obligately termite-symbiotic species. The fungal mycelia are cultivated in sponge-like combs built from termite-digested plant matter in the underground galleries of termite nests. Fungus-growing actively regulate the microclimate of the fungal galleries in order to maintain favorable conditions for fungal growth. The insects collect plant matter from around the nest and deposit it into fungus combs in the form of partly indigested fecal material. Fungal symbionts degrade lignocellulose of harvested plant material and the gained energy is utilized by the whole symbiotic consortium. In addition, fungus combs allocate nitrogen to fungal nodules which are then specifically supplied to support egg production and larval growth. While recent studies on termite symbioses have shed light to some aspects of these complex biological systems, many fascinating topics remain poorly understood and await further research.
Host: Prof. Dr. Silke Werth
11.05.2022 um 4:15 Uhr und Präsenz: Prof. Dr. Regine Claßen-Bockhoff, Johannes Gutenberg-Universität Mainz, Germany.
Black spots, galls and open questions: The evolution of dark-centred umbels in Apiaceae
The wild carrot (Daucus carota) is famous for its black flowers usually interpreted as structures mimicking flies or galls. Such dark centers are, however, not unique in the wild carrot, but evolved several times in parallel in at least seven genera from six different clades of the Apiaceae. Interestingly, all of these species occur in an area ranging from the (Eastern) Mediterranean to SW Asia. Is there anything specific in this area stimulating the formation of black-centred umbels? Using Daucus carota and the Turkish species Artedia squamata and Echinophora trichophylla as examples, the talk informs about the morphology of the dark structures, the plants’ architecture and breeding systems, the broad range of floral visitors, their behavior and response to manipulative experiments in the field. The black structures most likely evolved as inherited abnormalities and were stabilized by selection. Given promiscuous pollination, they are not addressed to a single pollinator guild. Instead, they offer shelter or mimic conspecifics, prey, enemies or galls dependent on the visitor species. The main pollinators in Turkey are beetles and the appearance of black spots reminds on beetle marks known from the area. It is, thus, possible that the dark centers evolved in adaptation to beetles without closely specializing on them.
Host: Prof. Dr. Marc Gottschling
18.05.2022 um 18:30 Uhr und Präsenz: Die Mischung macht’s - Hybride in Natur und Kultur
Dr. Thassilo Franke, BIOTOPIA – Naturkundemuseum Bayern
Forscher, Freigeist und Exzentriker - zum 200. Geburtstag des Evolutionspioniers Fritz Müller
Am 21. März jährt sich zum 200. Mal der Geburtstag von Johann Friedrich Theodor (Fritz) Müller, eines bedeutenden Mitstreiters Charles Darwins und unermüdlichen Sammlers von Fakten und Argumenten für dessen Evolutionstheorie. Nachdem Müller 1852 durch den von protestantischem Dogmatismus und weltanschaulicher Intoleranz beherrschten Zeitgeist Preußens ins brasilianische Exil getrieben wurde, lebte er dort abwechselnd als Farmer und Lehrer und nutzte jede freie Minute für Naturbeobachtungen und Experimente. Auf seiner Farm in Blumenau beschäftigte sich Fritz Müller mit ähnlichen Kreuzungsexperimenten wie Gregor Mendel in Brünn, allerdings wählte er statt Erbsen Mais. Hätten die beiden Forscher von den Experimenten des jeweils anderen gewusst, wären gewiss keine 34 Jahre vergangen, bis Mendels bahnbrechende Entdeckungen die ihnen gebührende Beachtung erfahren hätten.
Der Vortrag von Herrn Dr. Thassilo Franke (BIOTOPIA – Naturkundemuseum Bayern) gewährt Einblick in das Leben eines genialen Forschers, liebevollen Pädagogen und barfußlaufenden Exzentrikers – des „Prince of Observers“, wie sein Freund Darwin ihn zu nennen pflegte.
25.05.2022 um 4:15 Uhr und Präsenz: Dr. Sebastian Hess, Biocenter, University of Cologne, Germany.
Exploring microalgae and their parasites: from species to molecules
Microscopic eukaryotes inhabit virtually every ecosystem on earth and show a stunning variety of cellular organisation, life styles and interactions with other organisms. In my lab at the University of Cologne, we study poorly known algae and protozoa with molecular and classical techniques to further explore their diversity and to understand how they interact and function on a cellular level. Of special interest are the conjugating green algae (Zygnematophyceae), which are the closest relatives of the land plants and display interesting ecological and cellular adaptations. For example, some terrestrial lineages of these algae face increased solar radiation and produce colourful sunscreen compounds of yet-unknown chemical structure. In addition, the zygnematophytes are targeted by parasitoid protozoa of different eukaryotic supergroups (e.g. vampyrellid amoebae and highly-specialised flagellates). We combine a broad organismic understanding with ‘omics-informed cell biology’ to uncover how these heterotrophs recognise and perforate the algal cell walls, and how their feeding strategies evolved. It turns out that the interactions with the algal cells depend on diverse carbohydrate-active enzymes, some of which belong to vastly understudied enzyme families and represent a nearly untapped resource for biotechnology.
Host: Prof. Dr. Gudrun Kadereit
01.06.2022 um 4:15 Uhr und Online: Prof. Dr. Pavel Škaloud, Charles University, Prague, Czech Republic.
How to find the best partner: Insights into the mysterious world of symbiotic algae
Lichens and corals are symbiotic associations that have some striking similarities. Though these symbioses represent unique partnerships of different groups of organisms, they share many biological characteristics, including symbiont transmission, species richness differences, symbiont specialization and switching, and habitat adapted symbioses. Although the formation of symbiotic interaction represents a crucial step of lichen symbiosis development, the knowledge on how lichen-forming fungi acquire compatible partners is quite limited. Our investigations of symbiotic associations in rock-dwelling lichen communities of Central Europe uncovered the existence of a huge interconnected system of relationships among mycobionts and their photobionts. Interestingly, we found several photobionts that never associated with sorediate or isidiate lichens, meaning that these photobionts are most likely to have entered the community from outside. This finding emphasizes the role of free-dispersing photobionts in the establishment and maintenance of lichen guilds.
Host: Prof. Dr. Silke Werth
08.06.2022 um 4:15 Uhr und Online: Prof. Dr. Susana Coelho, Max Planck Institute for Developmental Biology, Tübingen, Germany.
Evolution of the sexes: insights from the brown algae
Sexual reproduction is an ancient and conserved feature of life on earth. However, the mechanisms that determine the sex of an individual are not evolutionary conserved, but are mesmerizingly diverse and have had rapid turnover rates during eukaryotic evolution. What drives the surprising evolutionary dynamics of such a fundamental process? What are the mechanisms underlying switches between sex determination systems? Are all sex chromosomes equal in terms of origin and evolutionary trajectories? The answers are complex but the ongoing genomic revolution and the use of alternative model organisms is already shedding light on sex chromosome diversity and evolution. I will describe how recent work in our group using brown algal models is contributing to this dynamic field of research.
Host: Prof. Dr. Dierk Wanke
22.06.2022 um 4:15 Uhr und Online: Dr. Holger Thüs, Staatliches Museum für Naturkunde Stuttgart (SMNS), Germany.
Explorations on the margins of the lichen lifestyle – aquatic and subaquatic lichens
The lichen symbioses is a common lifestyle in fungi, algae and cyanobacteria from habitat types where frequent and radical changes of water availability occur, or with extensive periods of drought. Typical aquatic and sub-aquatic environments instead are usually dominated by more vigorously growing microbial films, bryophytes or vascular plants. Freshwater lichens were long regarded as a generally rare, declining and species poor ecological group. This perception is challenged by new results based on randomized sampling strategies in Baden-Württemberg, targeted re-collecting at historic sites across Germany and worldwide studies into the underestimated diversity of aquatic and subaquatic lichens. In a combination of morphological, molecular and culture based assessments of the diversity of the components of aquatic and subaquatic lichens, much more structured diversity patterns start to emerge from the local to the global scale.
Host: PD Dr. Andreas Beck
29.06.2022 um 4:15 Uhr und Online: Prof. Dr. Peter C. van Welzen, Naturalis Biodiversity Center, Research group Tropical Botany, Leiden, The Netherlands.
Morphological flower adaptation to obligate moth pollination mutualism in Leafflower plants (Phyllanthaceae)
Many leafflower plants (Phyllanthaceae tribe Phyllantheae) are pollinated by leafflower moths (genus Epicephala, Gracillariidae). This is a similar system as with Figs and Yuccas. The flowers get pollinated and the moths receive shelter and can consume part of the developing seeds. Female moths actively visit staminate (male) flowers to collect pollen and then move to the pistillate (female) flowers to pollinate them, after which they deposit an egg either between the sepals and ovary or in the ovary. This obligate pollination mechanism originated five times in the Phyllantheae and the flowers seem to adapt to the pollination to increase the efficiency. Examples will be given which show that the staminate flowers become more erect and rigid and the stamens become generally united, while in the pistillate flowers the stigma surface reduces, either by a reduced length of the stigmas or by folding the stigmas together into a pyramidal cone with the receptional part on the inside.
Host: Dr. Hans-Joachim Esser
13.07.2022 um 4:15 Uhr und Präsenz: Dr. Elizabeth Joyce, Systematics, Biodiversity and Evolution of Plants, Ludwig-Maximilians University of Munich, Germany.
Untangling the effects of the Sunda-Sahul Floristic Exchange on the Southeast Asian and Australian flora
The convergence of the Sunda continental shelf (Peninsular Malaysia and parts of Indonesia and the Philippines), the Sahul continental shelf (Australia and New Guinea), and Wallacea from c. 25 Mya is one of the most significant events in global biogeography. The collision resulted in widespread geological change in the region, and facilitated the exchange of Sundanian and Sahulian floras that had evolved in isolation (the ‘Sunda–Sahul Floristic Exchange’ (SSFE)). This exchange has fascinated scientists since the time of Alfred R. Wallace, whose observations of disjunct Sundanian and Sahulian biota in the region made significant contributions to the burgeoning field of biogeography. Yet despite the long history of research on the topic, much remains to be understood about the effects and drivers of the SSFE — knowledge that is critical for understanding the modern flora, and how best to conserve it. Recent advancements in technology and data availability present an opportunity to gain a more comprehensive, accurate and nuanced understanding of the SSFE through space and time. In this seminar, I will give an overview of the SSFE, and present new insights into its patterns and drivers gained from floristic, phylogeographic and phylogenetic data.
Host: Prof. Dr. Gudrun Kaderei
20.07.2022 um 18:30 Uhr und Präsenz: Die Mischung macht’s - Hybride in Natur und Kultur
Dr. Ulrich Schliewen, Zoologische Staatssammlung München
Artbildung durch Hybridisierung im Reich der Fische
Mit mehr als 35.000 Arten sind die Fische die artenreichste Wirbeltiergruppe. In manchen afrikanischen Seen schwimmen mehrere hundert endemische Arten, die dort in geologisch kurzen Zeiträumen entstanden sind. Die Genese dieser enormen Artenvielfalt in so kurzer Zeit ist nicht ohne den Beitrag von Hybridisierungen erklärbar. Mit genomischen Methoden ist es seit wenigen Jahren möglich, den Beitrag von Hybridisierung zu dieser manchmal regelrecht "explosiven Artbildung" besser zu verstehen. Allerdings stehen wir erst am Anfang der Forschungsreise.
Ob es um einheimische Renken, um afrikanische oder mittelamerikanische Buntbarsche oder um Saiblinge aus der ostsibirischen Permafrostregion geht - fast immer kann eine Beteiligung von Hybridisierung zur Artbildung genomisch nachgezeichnet werden. Im Vortrag von Herrn Dr. Ulrich Schliewen (Zoologische Staatssammlung München), geht es auf eine Reise zu den Lebensräumen dieser Arten aber auch in die Welt der Fischgenome.
14.09.2022 um 18:30 Uhr und Präsenz: Die Mischung macht’s - Hybride in Natur und Kultur
Dr. Frank Blattner, Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK)
Tragen Hybride und Polyploide nachhaltig zur Biodiversität bei?
Durch Hybridisierung (Kreuzung zwischen Arten) und Polyploidisierung (Vervielfachung der Chromosomensätze) entstehen Organismen mit neuen Genotypen, die sich in ihren Eigenschaften teils deutlich von den Ausgangsformen unterscheiden. Am Beispiel von Krokussen und Wildgersten stellt Herr Dr. Frank Blattner (Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung) Prozesse vor, die zu neuen Genotypen, Ökotypen und Arten führen. Diskutiert wird, wie groß der langfristige Beitrag von Hybridisierung zur Artenvielfalt ist.
