Assistant professor Dr. Roey Angel
Dr. Roey Angel completed his doctoral work on methane turnover in upland soils at the Max-Planck Institute for Terrestrial Microbiology in Marburg, Germany. After post-doc training at the University of Vienna, Austria, he established the Anaerobic and Molecular Microbiology Lab at the Biology Centre of the Czech Academy of Sciences in České Budějovice, Czechia. In addition, Dr. Angel is an assistant professor at the University of South Bohemia and teaches microbiology at the international bachelor’s programme. Dr Angel’s lab is interested in deciphering how terrestrial communities of microorganisms, on a micro scale, control the cycling of nutrients on landscape scales. In particular, the group focuses on anaerobic processes in soil aggregates, biological soil crusts and arthropod guts. Particular attention is given to processes and effects of interest to society, such as the turnover of greenhouse gases and response to stress originating from climate change.
Redox conditions and trophic preferences shape the millipede gut microbiome
Millipedes (Diplopoda) are keystone macrodetritivores in many terrestrial ecosystems after termites and earthworms, devouring 10-36% of the annual litter. Therefore, they contribute to soil formation and are essential ecosystem engineers. Despite their ecological importance, it remains unclear whether millipedes are cellulolytic and their microbiome’s role in the diet. We elucidated and manipulated the millipede microbiota to study its ecological role and importance to the host. First, using a survey of 11 species, we show that the gut diversity is species-specific but can be clustered into three large groups according to the gut redox conditions. Using metagenomics and metatranscriptomics, we show that despite significant differences in taxonomic composition, two model millipede species shared most of the enzymatic metabolic functions, including CAZymes and nitrogen and sulphur turnover. Surprisingly, the most abundantly transcribed CAZymes involve chitin degradation rather than cellulose. Analysis of the millipede virome also showed that the two species contained different viruses but that chitin-degrading CAZymes were, in both cases, the most common auxiliary metabolic genes (AMGs).
Further experimental work using antibiotics dramatically affected microbial functions and population, but with minimal effect on the millipedes. Despite the presence of fermenting ciliates with associated methanogens, chemical suppression of methanogenesis (and hence also of fermentation) did not affect the millipedes. Lastly, RNA-stable-isotope-probing showed that fungi were labelled faster than the bacteria and that many non-fermenting bacteria were also labelled.
Our results represent the first in-depth analysis of the millipede microbiome and demonstrate that fungivory is more important than fermentation.
