Systematics, Biodiversity and Evolution of Plants
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Botany Seminars

A joint seminar of the section Systematics, Biodiversity & Evolution of Plants, the Botanische Staatssammlung München and the Botanical Garden München-Nymphenburg

When?  

  • Wednesdays at 4:15pm (during the semester)

Where?

  • Small lecture hall (Room 109) Botanical Institute, Menzinger Str. 67, 80638 München.

Program

10 April 2024 at 3:15pm: Prof. Dr. Susanne S. Renner, Washington University in St. Louis, U.S.A.

Spores before sporophytes and sporophytes before archegonia? The evolution of the land plant life cycle

Host: Prof. Dr. Gudrun Kadereit

 

24 April 2024: Laura Ávila Robledillo, Max Planck Institute of Plant Breeding Research, Department of Chromosome Biology, Cologne, Germany.

Initial insights about mono- and holocentromeres in carnivorous Drosera species

Sundews are carnivorous plants that grow in nutrient-poor habitats. They are distributed globally, with more than 200 species described. In addition to carnivory, sundews are reported to have great diversity of genomic and chromosomal features. The chromosomes of sundews have been studied for over a century revealing extraordinary variability in chromosome number and ploidy across species. But perhaps, one of the most fascinating features of sundews chromosomes is the fact that several species analyzed within the genus Drosera lack a visible primary constriction, leading to the assumption that holocentricity is common in the genus. This is very exciting as it points to the occurrence of both monocentric and holocentric species in a single genus.
Combining genomics and cytogenetics we are analyzing the genomes of Drosera species differing in centromere organization. The development of specific centromere markers allows us to verify the centromere type of our set of species. Our preliminary data reveals for the first time, the different genome architecture of mono- and holocentric Drosera and suggest that satellite repeats are associated with centromeres in both types. Synteny analyses among the selected Drosera species and its sister clade Nepenthes gives insights into the karyotype evolution of the group showing that events of fission and fusions are common in the group.
This work could provide the bases for the understanding of the genomic changes associated with holocentricity as well as the drivers of this transition.

d-capensis
Photo: Drosera capensis

Host: PD Dr. Andreas Fleischmann

 

22 May 2024: Dr. Ekaterina Pushkareva, Botanical Institute, University of Cologne, Germany.

Biocrusts from the High Arctic: microbial community composition and their potential functions

Biological soil crusts (biocrusts) are essential components of polar ecosystems and play an important role in shaping the fragile environments of the Arctic and Antarctic regions. Biocrust are composed of a diverse array of bacteria, fungi, algae, lichens, and bryophytes that interact with the soil particles, creating a fragile layer on the soil's surface. They serve as pioneers in barren landscapes, contributing significantly to soil stability, nutrient cycling, and moisture retention. Understanding their composition, distribution, and ecological functions is crucial for comprehending the complex dynamics of polar ecosystems. Investigating these crusts offers insights into their resilience against extreme conditions and their pivotal role in maintaining the overall biodiversity and ecological balance in these harsh, yet vulnerable, polar environments.

pushkareva

Host: PD Dr. Andreas Beck

 

29 May 2024: Dr. Alistair Leverett, University of Cambridge, England.

Crassulacean Acid Metabolism and Succulence in the Genus Clusia

Within the neotropical genus, Clusia, there is remarkable interspecific diversity in photosynthetic and hydraulic physiology. This genus contains species spanning the entire C3-CAM continuum: some are obligate C3; others constitutive CAM; whilst many more exhibit some form of C3-CAM intermediate phenotype. Furthermore, there is substantial variation in the water relation traits of Clusia leaves, particularly variation in the turgor loss point (i.e. the wilting point) and hydraulic capacitance. As a result of this phenotypic diversity, Clusia can be used as a model to conduct comparative analyses that address a range of research objectives. To this end, I will answer three questions I addressed during my PhD research: 1) How do CAM and the turgor loss point contribute to the distributions of species across a precipitation gradient, and what can this tell us more generally about drought adaptations? 2) What anatomical adaptations are associated with CAM, and can we move beyond correlative analyses in non-transformable taxa? 3) Does CAM require elevated nocturnal respiratory rates? Overall, these questions highlight the power of using non-model, phenotypically diverse taxa to understand the ecophysiology of CAM and succulence.

leverett

 Host: Dr. Thibaud Messerschmid

 

andrew-rozefelds05 June 2024: Dr. Andrew Rozefelds, Principal Scientist and Curator of Palaeobotany at Queensland Museum, Australia.

Green History - The Cenozoic Fossil Record of Northern Australia

Integration of fossils into phylogenetic analyses can provide significant insights into both the origins and history of plant morphological traits and minimum ages of the phylogenetic lineages under study. Underpinning this is the need for well supported stratigraphic information that allows the ages of fossils to be determined with confidence. Intraplate volcanism during the Oligocene and Miocene occurred extensively throughout eastern Australia. Weathering of these volcanic rocks led to mobilisation of silica which resulted in the permineralisation of floras buried by volcanic activity, and the age of these floras can be inferred from radiometric dates from the associated volcanic provinces. While these silcrete floras are little studied their extraordinary preservation makes it possible to critically compare them with modern plants. Plants preserved in these silcretes are usually permineralised and preserve internal anatomy and cellular structures. Silicification not only preserves plants but also leaf litter on the forest floor and even the underlying soil containing roots and root nodules. Current research on fossil floras from northern Australia will be highlighted and is providing new insights into evolution and history of the modern Australian flora. Terrestrial (ground-dwelling) ferns are often conspicuous elements in these silcretes because they have been preserved in situ. Some of the challenges in interpreting the phylogenetic signal from these fossil plants will also be discussed.

Host: Dr. Elizabeth Joyce


12 June 2024: Dr. Petr Sklenář, Charles University in Prague, Czech Republic.

Plants from the tropical high Andes – evolution and ecology 

The Tropical Andes, a hotspot of biodiversity, harbour several textbook examples of adaptive radiations in plants. Lupins, gentians, valerians, espeletias, what do they have in common? Why are they so diverse? The „summer every day, winter every night“ of the tropical high mountains provides unique environmental settings. But how can this be linked to plant diversification? The talk offers colorful plants, many questions, and maybe some answers.

espeletia-paramo-angel
Photo: Espeletia in Páramo Angel

Host: Dr. Simon Pfanzelt

 

19 June 2024: Dr. Juan Carlos Villareal, Université Laval, Québec, Canada.

Eco-evolutionary dynamics in cryptogams: Bryophytes, fires and reindeer lichens

Host: Prof. Dr. Julia Bechteler

 

26 June 2024: Prof. Dr. Marc Gottschling, Systematics, Biodiversity and Evolution of Plants, LMU Munich, Germany.

Metabarcoding project 'eintauchen'

zinssmeistercoverFreshwater plankton in temperate habitats shows a strong seasonality to effectively use ecological resources and to survive unfavourable environmental conditions. Changing water temperature has been recognised as the key ecological variable driving the rise and fall of species and communities. In the metabarcoding project 'eintauchen', samples were collected weekly over the course of a year from six ponds in our botanical garden that are characterised by minimal fertilisation and the absence of pesticides. Despite their geographical proximity and the common water supply from the River Würm, the six ponds exhibited great diversity in their taxonomic composition and considerable seasonal variation. Using the 200 most abundant ASVs, the Decision Tree Regressor machine learning tool was used to test the extent to which temperature has an influence on their seasonal variation. The K-Means Clustering machine learning tool identified only a quarter of the 200 most abundant ASVs as organisms, whose course is altered by water temperature. Instead, another quarter of the ASVs studied are more likely to be driven by changing day length, with inflection points (and mathematical extremes of their derivatives) two weeks ahead of the temperature curve in spring and seven weeks ahead of the temperature curve in autumn, respectively. Length of daytime is a more reliable ecological variable over the course of the seasons than temperature, which appears used by more protists at middle latitudes than previously assumed. These findings are consistent with the responses of many flowering plants to daytime length variations in temperate habitats.

After the talk: Depending on the weather, the speaker suggests reviving an old tradition of our institute and meeting in the Hirschgarten beer garden for further discussion after the talk. Soccer will be playing at that time, but not broadcasted at the site - so that there should be enough space available for us.

 

Tuesday 09 July 2024: Prof. Dr. Richard Merrill, Evolutionary Biology, LMU Munich, Germany.

Evolutionary Genetics of Visual Preferences: Beauty, Brains and Butterfly Diversity

Visual signals are an important driver of mate choice and sexual selection in both plants and animals. Although we increasingly understand the genetic basis of the signals themselves, we still know little about the genes underlying the corresponding preferences, or how they evolve. I will talk about a long-term project focused on the genetics and sensory ecology of visual preferences that are known to contribute to speciation in tropical Heliconius butterflies. By combining population genomic and gene expression analyses, data from hundreds of behavioural experiments, and genome editing using CRISPR/Cas9, we have been able to link a specific gene to the evolution of visual preference behaviours. I will discuss how these results i) implicate a role for interspecific hybridization, and adaptive introgression, during the evolution of behaviour; and ii) also show how visually-guided behaviours contributing to adaptation and speciation can be encoded within the genome. Finally, I hope to introduce some emerging work in which we are attempting to place these results within the broader context of visual evolution, including the specific cues involved and shifts in visual acuity associated with changes in habitat.

Host: Prof. Dr. Gudrun Kadereit

 

bradshaw10 July 2024 via Zoom: Dr. Alexander Bradshaw, Postdoctoral researcher at the Natural History Museum of Utah, USA.

Natural History, Evolution, and ongoing studies in the "magic mushroom" genus Psilocybe

Despite the medicinal promise that psychoactive compounds such as Psilocybin and Psilocin have shown, the mushroom-producing organisms that create these compounds, Psilocybe, have largely gone unstudied. This seminar will discuss the history of Psilocybe mushrooms, why they are difficult to work with, systematic studies on their psychoactive properties, and ongoing projects related to their diversity and evolution.

Join the Zoom meeting

 


Photo: Dr. Bradshaw holding a Psilocybe zapotecorum specimen collected in Mexico

Host: Dr. Anže Žerdoner Čalasan

 

17 July 2024 at 11:15am: Prof. Dr. Eva H. Stukenbrock, Environmental Genomics, Botanical Institute, CAU Kiel and MPI for Evolutionary Biology, Plön, Germany.

Microbial interactions and co-evolution in the plant phyllosphere

Plants are associated with a variety of microorganisms. Some microbial species are highly specialized to a plant-associated lifestyle and play a detrimental role in plant health either by promoting growth or conferring disease. In spite of their fundamental importance, we know surprisingly little about the ecology of these microbial species. We use the fungal grass pathogen Zymoseptoria spp as a model system to study fungal evolution in the context of molecular interactions with the plant host and the plant-associated microbiota. The species Z. tritici has co-evolved with wheat during domestication and provides an excellent model system to study fungal adaptation to plant invasion and colonization. Genome and transcriptome analyses have elucidated how host specialization of this pathogen has involved the acquisition of adaptive substitutions in genes encoding secreted proteins as well as changes in gene expression. To understand the underlying molecular basis of successful invasion of wheat leaves by Z. tritici, we have used a metabolomics approach. Hereby, we demonstrate that Z. tritici, in susceptible hosts, is able to suppress and manipulate multiple biosynthetic pathways of wheat and notably pathways involved in immune responses during infection. Interestingly, suppression of the plant immune responses conferred by Z. tritici is so efficient that it impacts the ability of other microbial species to colonize the plant tissue, even in distal areas of the leaf not colonized by the fungus. Consistent with this observation we find that Z. tritici produces a large diversity of anti-microbial compounds, which may be important for the pathogen to co-exist with the wheat-associated microbiota. Our findings suggest that host specialization of pathogens not only entail specialization to a given host, but also to the host microbiota.

Host: Prof. Dr. Gudrun Kadereit

 

 


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