Sessions (Topics)

  • Pathogenic protists
  • Protists as hosts/ endosymbionts
  • Soil protists
  • Taxonomy, systematics, and barcoding
  • Symbiosis and endosymbiosis
  • Mixotrophy
  • Extreme environments and climate change
  • Biodiversity and biogeography
  • Environmental genomics & bioinformatics
  • Molecular evolution genomics & transcriptomics
  • NGTax Next Generation Taxonomy
  • Citizen Science and Science communication
  • Anaerobic protists
  • Bioinformatics tools
  • Protists as model organisms
  • Protists as indicators
  • Cell biology
  • Evolution from unicellular to multicellular
  • Mutualistic symbioses

Session Abstracts

Session Environmental genomics & bioinformatics

Tristan Cordier (Chair)

Since  about a decade, high-throughput sequencing of environmental nucleic  acids, i.e. environmental genomics, has revolutionized our understanding  of the ecology and evolution of protists. From field studies to  controlled experiments, from sediment/soil/water/air metabarcoding to  cell-sorted metatranscriptome, from short to long-reads sequencing, from  broad community profiling to phylogenetic placements, this session aims  to showcase the latest conceptual and technical advancements in  environmental genomics and computational biology to address protists  ecological and evolutionary questions. We especially welcome submissions  from early careers scientists.

Session Molecular Evolution - genomics/transcriptomics

Fabien Burki (Chair)

Genomic-scale  datasets are generated faster than ever, and excitingly are now  available for all supergroups of eukaryotes–including poorly known  protist lineages. This diversity of genomes/transcriptomes available  provides a fantastic opportunity to study the molecular evolution of  protists, from comparative analyses of closely related species to broad  comparison across all eukaryotes. In this session, we would like to  convene researchers that use genome data to address evolutionary  questions of protists including but not limited to: infer relationships  by phylogenomics, evolutionary transitions, or genome-based inferences  of cellular features and behavior. We especially welcome abstract  submission about enigmatic groups of protists that are being studied  thanks to advances in culture-free genomics.

Session Soil Protists

Edward Mitchell (Chair)

Protists are a major component of soil biota both in terms of diversity and functional importance. Yet they remain less studied than other groups of soil organisms. The methodological limitations that explained this have now mostly been overcome and we see a clear increase in number of studies, especially those using high throughput sequencing (HTS) approaches to address biodiversity and function questions. This makes it all the more crucial to discuss, as a community, the current state of the art, knowledge gaps and ways to fill them. In this session I would like to invite colleagues to present talks aiming to cover the many topics directly related to soil protists including:

  • Natural ecosystems and agro-ecosystems
  • Biodiversity (direct observation and HTS)
  • Taxonomy (morphology and molecular)
  • Phylogeny and evolution
  • Biogeography / Macroecology
  • Functional ecology – links to ecosystem function
  • Feeding habits, trophic roles

A mix of case studies and more general overviews/review would be welcome.

Session Taxonomy, systematics, and barcoding

Peter Vďačný (Chair)

Systematics  Agenda 2020 emphasized the description and classification of  biodiversity as a focal activity in the 21st century. Nowadays, the  integrative approach is a preferred way of studying the biodiversity of  both free-living and symbiotic protists. This session aims to showcase  the recent advances in taxonomic and systematic research across various  lineages of protists. We especially welcome submissions based on  state-of-the-art morphological and phylogenetical methods.

Session Citizen science and science communication

Brigitte Gschmeidler and Karin Garber (Chairs)

The collaboration of researchers with amateurs (citizen scientists) in science projects has become quite popular within the last decade. At best it becomes a win-win situation for both sides. However, citizen science projects with focus on microbiology are still a challenge. Low threshold science communication may be one of the first steps for amateurs to get in touch with research. Why not start earlier and involve already children and teenagers in citizen science projects? This session gives an insight in citizen science and science communication activities with regard to microbiology for all age groups.

Session Mixotrophy

Stefanie Moorthi and Matthew Johnson (Chairs)

Mixotrophy is a widespread nutritional mode in aquatic protists combining the processes of phagotrophy and photosynthesis within a single organism. The ubiquity of this phenomenon underscores the ecological and evolutionary flexibility of dual metabolism for acquiring energy and nutrition. The rich diversity of mixotrophs can be loosely organized between constitutive (possessing permanent plastids) and non-constitutive (harboring kleptoplastids or symbionts) organisms, which run the gamut of generalized to specialized prey selection and reliance upon photosynthesis. In this session we hope to showcase diverse researchers using cell-targeted to omics-driven approaches, to illuminate the biology, behavior, and ecology of mixotrophs in diverse ecosystems. We especially welcome submissions from early careers scientists.

Session Anaerobic Protists

Ivan Cepicka (Chair)

Anoxic freshwater and marine sediments as well as the digestive tracts of animals are inhabited by diverse communities of protists, which are notable for having transformed mitochondria variously adapted to anaerobic metabolism. The final metabolic byproducts of these so-called mitochondrion-related organelles usually include molecular hydrogen, and, as means for its disposal, anaerobic protists have repeatedly entered into symbioses with bacteria or archaea that utilize hydrogen. These syntrophic symbioses have been recently attracting the attention of biologists because their intersection with aspects of climate science, including production of the greenhouse gas methane, poisonous hydrogen sulfide, and denitrification of the environment. Despite the obvious importance of anaerobic protists, their diversity is still only poorly documented. This symposium covers all aspects of the biology of anaerobic protists, both free-living and endobiotic, as well as their syntrophic symbioses with prokaryotes.

Session Ciliates as model organisms

Alexey Potekhin and Martin Simon (Chairs)

Ciliates serve as model organisms in different biological disciplines. Studies on ciliates have provided highly valuable insights into genetics and epigenetics, nucleus functions, non-coding RNA functions and chromatin structure, cell biology and physiology, cell signalling and cytoskeleton, structural heredity, evolution of eukaryotic cells, and much more. Molecular sequencing and especially genomics of ciliates continue to expand, now including more and more representatives of less known groups or from yet undersampled habitats, thus increasing the choice of the experimental models objects within the Ciliophora. The session will cover a broad spectrum of actual highlights in ciliate biology.

Session Algae and cyanobacteria as endosymbionts

Tatyana Darienko and Thomas Pröschold (Chairs)

Protists such as ciliates, amoebae and foraminifers often live in symbiosis with algae and cyanobacteria. The algal endosymbionts known as zoochlorellae and as zooxanthellae belong to different lineages of green and red algae and stramenopiles (dinoflagellates, and chrysophytes). Cyanobacteria occur as cyanelles in testate amoebae and marine diatoms. This session aims to demonstrate the current status of the biodiversity and evolution of these endosymbionts based on phylogeny and phylogenomics in comparison with their free-living relatives. Studies focusses on interactions between host/symbionts and their biogeographical pattern are also welcome. We especially encourage submissions about non-model organisms.

Session Terrestrial algae and the evolutionary origin of a multicellular land flora

Jan De Vries and Sebastian Hess (Chairs)

Algae from various lineages have successfully established a foothold on land. Their communities dwell in soil and surfaces such as rocks. Yet only once did terrestrial algae rise above their substrate and give rise to the dominant land flora: the streptophyte algae from which the embryophytes emerged. Irrespective of their evolutionary footprint, all terrestrial algae exhibit instructive traits, including tolerance to terrestrial stressors, specialized metabolism, and multicellular growth. In this session, we would like to capture the phylodiversity of terrestrial algae and their traits.

Session Protists associated with crops in land plants and aquaculture

Sigrid Neuhauser (Chair)

Protist parasites associated with land- and aquatic crops include organisms from diverse taxonomic groups such as Oomycetes, Rhizaria (e.g. Phytomyxea, Vampyrellida, Cercozoa) or Excavata (e.g. Phytomonas). Some of them are well known, however, knowledge about the impact and biology of most of these interactions remains scarce. Over the last years new tools allow us to detect, identify, and study those organisms in a more targeted way. This session aims to unite research on all groups of protists that is associated with plants or aquatic crops and aims to understand novel and established biodiversity, or which provide insights into their biology and ecology.

Session: Extreme environments and climate change 

Nicole Aberle-Malzahn and Stephen Wickham (Chairs)

Protists inhabit all types of terrestrial and aquatic environments and show high adaptation potential and trait flexibility in relation to environmental conditions. If Baas Beckling’s hypothesis that “everything is everywhere but the environment selects” is true, then extreme environment can be expected to show maximal selection. These environments are characterized by conditions beyond the optimal range, including extreme pH, temperature, salinity, radiation, and pressure conditions that are found i.e. in polar, desert, high altitude and deep sea habitats. However, despite such harsh conditions, extreme environments harbour a large variety of protists, thus contributing considerably to global biodiversity and ecosystem functions. Extreme environments harbour unique and complex protist communities with a high adaptative potential and flexibility to changes in environmental conditions. This session aims for contributions focussing on auto-, mixo- and heterotroph protist communities from extreme environments and their responses to changes in environmental conditions including climate change impacts. Studies from observational and experimental studies are welcome.

Session NGTax Symposium

Giulio Petroni and Valentina Serra (Chairs)

Next Generation Taxonomy (NGTax) is a multidisciplinary workflow recently proposed, which integrates the holobiont concept into traditional and integrative taxonomy, leveraging the power of high-throughput DNA sequencing. In detail, this approach combines traditional taxonomic techniques (living, observation, staining, morphometry), to ultrastructural (electron microscopy), molecular, phylogenetic, and genomics analyses of the ciliate host and its symbionts, if any. In particular, the ciliate mitogenome and obligate symbionts are proposed as additional taxonomic descriptors, in order to obtain the most comprehensive characterization of the organism(s). Whenever possible, also the complete genome of the symbiont is provided. In this section we present scientific contributions dealing with ciliate’s description and redescription, that move in the direction of NGTax approach, as well as works on host-symbionts interaction, and/or genomics/phylogenomic studies stemming from this research field.

Session Pathogenic protists

Vyacheslav Yurchenko (Chair)

At least 15% of known protists have symbiotic or parasitic life styles with considerably varying host-specificities. In principle, any other eukaryotic organism can function as host, including humans. Pathogenic protists do not only use other organisms as hosts, but also cause disease. Some of these microorganisms are of prime importance for human and animal health and many of the diseases caused by protists are neglected. Moreover, many pathogenic protists are opportunists and cause more severe disease in immunocompromised individuals.

Session Cell Biology

Renate Radek (Chair)

Protists are excellent model systems for studying aspects of cell biology. In this session, different mechanisms and structures of a broad spectrum of organisms are presented. Topics are contractile vacuoles and membrane trafficking in flagellates and ciliates, cytoskeletal elements in preaxostylans, roles of chitin in cercozoans, key enzymes for starch synthesis in chromerids and Apicomplexa, and ethylene signaling in glaucophytes.