Winter semester 2022-2023
02.11.2022 in person: Dr. Sebastian Höhna. Palaeontology and Geobiology, Ludwig-Maximilians University of Munich, Germany.
Estimating diversification rates from phylogenies
Host: Dr. Elizabeth Joyce
09.11.2022 in person: Dr. Mona Schreiber. Philipps-Universität Marburg, Germany.
The greening ashore, how plants changed climate before we did
Land plants make up most of today's biomass, they produce oxygen, fix carbon and it was their evolution that made life on land as we know it possible. The history of their development takes us back to the emergence of eukaryotes, followed by the photosynthesising plastid and the subsequent changes in the atmosphere as well as constantly rising molecular and morphological complexity.
Coming from salt water, algae began to adapt to life in fresh water and along the lineage of the Streptophyta further to drought. 500 million years ago, land was mostly bare rock and provided a largely hostile environment for life. Adapted to drought and irradiation, however, a group of algae managed to colonise the land, paving the way for bryophytes, lycophytes, ferns and eventually seed plants to green up the Earth by their rapid diversification. With the greening ashore all other life also came to land, diversified and even gave rise to the evolution of our own species. The evolution of plants unfolded over hundreds of millions of years, thereby terraforming the terrestrial habitat and the Earth’s atmosphere. In our own short history, it is us humans who are now irrevocably changing the climate and the planet in the present Anthropocene.
Host: Prof. Dr. Gudrun Kadereit
16.11.2022 in person: Prof. Dr. Michael Lenhard. Universität Potsdam, Germany.
The genetic and molecular basis of stylar polymorphisms – supergenes that promote outbreeding
Plants have evolved several floral adaptations to promote outbreeding. One class of these are stylar polymorphisms. Individuals of species with such polymorphisms belong to one of two morphs that form flowers with male and female reproductive organs in separate, but reciprocal positions. As a result, self-pollination within the flowers of one morph is limited, while pollen transfer between flowers of the two morphs is promoted by the reciprocal organ placement. Male and female organs can be displaced along the proximo-distal axis (heterostyly), along the dorso-ventral axis (inversostyly) or the left-right axis (enantiostyly). We are studying the genetic and molecular basis of these polymorphisms in several model species and have identified the underlying supergenes, non-recombining chromosomal regions that contain individual genes responsible for the differences in male and female organ placement, as well as associated polymorphisms. I will present recent work on understanding the function of these genes and their evolution.
Host: Prof. Dr. Gudrun Kadereit
23.11.2022 online only : Dr. Olwen M. Grace. Royal Botanic Gardens, Kew, UK.
Water storage in succulent plants
The remarkable features for which xeric succulent plants are loved – curious shapes, textures and colours – are ecologically functional adaptations to drought-prone habitats. Succulents evolved a reservoir of water millions of years ago to sustain photosynthesis in desert-like conditions. In this presentation, I will share new research into the water storage features of xeric succulents in a phylogenomic context. These data provide insights into mechanisms for water storage as well as systematic relationships that have troubled taxonomists. Beyond their decorative beauty, the adaptations in succulent plants could become increasingly valuable to deal with climate change in hot, dry conditions – providing the rare and threatened species have been adequately conserved.
Host: Dr. Thibaud Messerschmid
30.11.2022 in person: Dr. Kenji Fukushima. University of Wuerzburg, Germany.
Linking genotypes and phenotypes in the light of convergent evolution
While some evolutionary innovations may be unique, convergent evolution produced many innovative traits, such as plant carnivory. To detect genotype-phenotype associations underlying convergent evolution, we developed a novel framework to measure the rate of genetic convergence. In this talk, I will show how our approach allows bidirectional searches for genotype-phenotype associations, even in lineages that diverged for hundreds of millions of years.
Host: PD Dr. Andreas Fleischmann
07.12.2022 online only: Dr. Agnes Dellinger. Universität Wien, Austria.
Buzz-pollination and pollinator shifts: exploring patterns and processes of flower diversification in the plant family Melastomataceae
Pollination by animals is regarded as a major driver of angiosperm evolution and the diversification of flowers. While the impact of pollinators in shaping floral diversity has been demonstrated extensively at macroevolutionary scales, we know much less about how biotic and abiotic environmental contexts influence plant-pollinator interactions and translate into macroevolutionary patterns. To address this gap in my talk, I will start out by outlining major patterns of flower diversity and flower trait functioning in the tropical plant family Melastomataceae. Melastomataceae have largely radiated in a functionally highly specialized pollination system, buzz pollination by bees, where pollen is only released from flowers when specific vibrations are applied. Approximately 96% of species employ this pollination strategy, and show an astounding diversity of floral phenotypes. Across the globe and across the Melastomataceae phylogeny, ca. 4% of species have shifted from bee pollination to different vertebrate pollination strategies, or generalized pollination. I will discuss the floral functional trait changes necessary for such shifts, and explore patterns of floral trait diversity (disparity) across Melastomataceae clades. Finally, pollinator shifts in Melastomataceae show a strong link to occurrence in high elevation ecosystems where bee pollinators are scarce. In the last part of my talk, I will present empirical experimental data from the plant tribe Merianieae to demonstrate that adverse climatic conditions in tropical mountains acted as major driver of shifts from bee to vertebrate pollination.
Host: Dr. Marie Claire Veranso-Libalah
14.12.2022 online only: Prof. Dr. Alexandra Nora Müllner-Riehl. Leipzig University, Germany.
Mountain biogeography: new insights gained from biodiversity and geodiversity data
Host: Dr. Elizabeth Joyce
18.01.2023 in person: Dr. James Hartwell. University of Liverpool, UK.
From genomes and transcriptomes to functional genomics and whole plant physiology: elucidating the molecular-genetic blueprint for Crassulacean acid metabolism in the genus Kalanchoë
In the face of climate change and the current global food security crisis, there is an urgent and pressing need to develop novel crops that are more water use efficient. Most major food and biomass feedstock crops perform a form of photosynthesis known as C3, which is comparatively poor at conserving water. A diverse range of species from desert and semi-arid environments have evolved a photosynthetic adaptation known as Crassulacean acid metabolism (CAM), which can increase water use efficiency between 10- and 20-fold. We have leveraged next generation sequencing technologies to decode the genomes and transcriptomes of several CAM species in the genus Kalanchoë. This has allowed us access to the genes responsible for the high water use efficiency of these plants. We are functionally characterising candidate genes in a number of ways, including switching them off in Kalanchoë, and switching them on in C3 species. We are also using PROMOTER::LUCIFERASE reporter constructs to understand the temporal control of key CAM genes in Kalanchoë. Our long term goal is to develop molecular tools to underpin the development of existing CAM crops as bioenergy feedstocks, and also the development of re-engineered C3 crops that can use CAM to sustain their growth and yield during prolonged periods of drought. This talk will describe our work to decode CAM genomes and transcriptomes and how we are using the knowledge gained alongside transgenic approaches to understand the minimal set of genes required for optimised CAM. A key focus of our work seeks to understand the circadian clock output pathway that optimises CAM relative to the daily light/ dark cycle, and we are also working to dissect the cell-signalling processes that mediate CAM stomata to open in the dark and close in the light. Furthermore, we studying the physiological diversity of CAM across the genus Kalanchoë, and investigating the genomic basis for the evolution of the CAM trait across this genus. Recent progress in these areas will be highlighted in this presentation.
Host: Prof. Dr. Gudrun Kadereit
25.01.2023 in person: Dr. Markus Sachse. Independent researcher in paleobotany, Munich, Germany.
The Miocene vegetation of Burtenbach near Gunzburg – what to learn from the past?
In several dozen sand pits of the North Alpine Foreland Basin, Middle Miocene fluvial sediments are being excavated, and with them fossil plant assemblages are frequently brought to light. Based on their composition, environmental and vegetation changes could probably be recorded in high spatial and temporal resolution for the pre-Alpine landscape of the Middle Miocene. Its analysis might be of high relevance in respect of the current climate warming. Using the example of the approximately 15.3 million year old clayey pond deposits in the Burtenbach pit, the identification of various vegetation units is demonstrated on the basis of over 100 leaf fossil taxa and palynomorphs.
Illustration: Middle Miocene landscape in the North Alpine Foreland Basin (Mauricio Antón)
Host: Dr. Andreas Gröger
01.02.2023 in person: Dr. Peter Grobe. Head of Biodiversity Informatics Leibniz Institute for the Analysis of Biodiversity Change. Museum Koenig, Bonn, Germany.
The Diversity Workbench framework at the Leibniz Institute for the Analysis of Biodiversity Change: From the collection object to FAIR data
The Leibniz Institute for the Analysis of Biodiversity Change is one of eight data centers in GFBio and NFDI4Biodiversity, which provides services in collection and research data management. At LIB, we explore the causal relationships of biodiversity loss. The information we deal with is from natural and cultural history collections, morphological and genetic analyses, surveys, environmental samples, and data flows from monitoring stations. This research is a holistic process in which all information is made available at all times to all relevant user groups, like project partners or the general public.
The diversity and volume of data continuously confronts us with new challenges, as the requirements for the information infrastructure are also constantly changing: from initial static web pages in the 1980s to database-supported dynamic web portals, highly linked and universally accessible computer actionable services are now necessary to make the information usable across disciplines for any questions and applications.
On the one hand, a well-structured and dynamically adaptable data infrastructure is important to meet this need; on the other hand, good networking with other stakeholders and data centers is a necessity for the successful provision of information according to the FAIR-Data principles, in order to keep the information accessible, comparable and understandable in the long term (more)
Download pdf with the presentation: The Diversity Workbench framework at the LIB: From the collection object to FAIR data
Host: Dr. Dagmar Triebel
08.02.2023 in person: Prof. Dr. Boas Pucker. Technische Universität Braunschweig, Germany.
Understanding the evolution of plant biosynthesis pathways through genomics
Technological progress in plant genomics enables the generation of high quality genome sequences for numerous plant species. While the generation of genome sequences is turning into a routine task, production of a high quality annotation remains a challenge. Especially the assignment of functional descriptions to predicted gene models is necessary to understand plant genomes. We developed several tools to support the identification of candidate genes involved in biosynthesis pathways and their regulation. This automatic annotation facilitates comparative studies across many plant species and in-depth investigations of specific traits. Of particular interest are specialized metabolite biosynthesis pathways due to the enormous biochemical diversity of natural plant products and the wide range of applications. It is possible to compare the presence and locations of genes across many plant species to gain insights into the evolution of biosynthesis pathways. The anthocyanin biosynthesis is one such pathway with products that are well known for their contribution to flower coloration. Anthocyanins are of interest in biotechnological application, have nutritional benefits, and serve as a model system for pigment evolution in the Caryophyllales. A combination of comparative transcriptomics and genomics revealed insights into the molecular mechanisms behind the phylogenetic distribution of anthocyanins in the Caryophyllales. Similar approaches are deployed to characterize the diversity of intracellular anthocyanin transport which is a largely unexplored aspect of anthocyanin biology.
Host: Dr. Christian Siadjeu
15.02.2023 in person: Dr. Filip Vandelook. Meise Botanic Garden, Belgium.
Ecology and evolution of embryo size in angiosperms
Seeds of angiosperms with a small embryo embedded in copious endosperm were first described in the 19th century. Later on, it became clear that such seeds commonly occurred in temperate forest herbs. However, it was not until the seminal work of Martin in 1946 that insight was gained on the distribution of seeds with small embryos and copious endosperm or perisperm in seed plants and its prevalence in early branching angiosperm orders, such as Nymphaeales and Magnoliales. Nowadays, fossil and phylogenetic evidence corroborates that early angiosperms dispersed endospermic seeds with small embryos. In angiosperms, a general evolutionary trend is observed towards seeds containing large embryos and little or no endo- or perispermic nutritive tissue, although this trend may just be a passive one, away from a lower boundary for relative embryo size. The adaptive significance of the embryo size relative to the size of the seed still offers plenty of food for debate. Newly compiled large data-sets and more advanced techniques for modelling and statistical analyses provide interesting opportunities to explore the questions on the evolution of embryo size, ecological correlates and its potential adaptive nature.
Host: Dr. Anze Zerdoner Calasan