Christian Kost

@kostchristian.bsky.social

Experimental ecology and evolution | microbes | evolution of metabolic interactions | cooperation | bacterial multicellularity.

Happy to share our latest work digging a bit more into what makes the the core microbiota of photosynthetic organisms convergent (or not!). Work performed @lipme-toulouse.bsky.social @cnrs.fr, in collaboration with @guan06rui.bsky.social @quadraminstitute.bsky.social tinyurl.com/3e958dt6 (1/10)

Environmental factors and microbe-microbe interactions drive the structure of the core microbiota of terrestrial microalgae

Plants and other photosynthetic organisms interact with their environment and surrounding microbiota through specialized associations. A global core microbiota has been proposed at high taxonomic levels, such as the order level. However, it remains unclear which environmental factors and how microbe-microbe interactions drive variation of this core microbiota at lower taxonomic resolution. Here, we leveraged the environmental diversity of 141 sites across the southwest of France to characterize algal populations, and their associated bacterial and fungal microbiota. We then performed a meta-analysis, combining these data with published datasets to formally identify the global core microbiota of terrestrial photosynthetic organisms, which comprises seven bacterial and five fungal orders. We next investigated diversity within this core microbiota and the environmental drivers shaping site-specific community composition. While environmental factors have a low impact on the total relative abundance of core orders, the core microbiota at the ASV-level is impacted by climatic factors, edaphic factors, and plant community descriptors. Using interaction network analysis, we finally explored how microbe-microbe interactions contribute to the assembly of stable core communities. Our results show that core ASVs occupy central positions in algal-associated microbial networks and that distinct core orders drive site-specific variation in core microbiota structure. Together, these findings highlight the importance of both environmental context and microbial interactions in shaping the composition and stability of the core microbiota associated with photosynthetic organisms. ### Competing Interest Statement The authors have declared no competing interest. European Research Council, 951444 – PATHOCOM, erc-stg-948219, EPYC Agence Nationale de la Recherche, ANR-10-LABX-41 Biotechnology and Biological Sciences Research Council, https://ror.org/00cwqg982, BB/ X011054/1, BBS/E/F/000PR13631

tinyurl.com

really enjoyed this, finally some really solid data on the question of whether cross-feeding actually matters in soil. A great mix of wet-lab experiments and genomics that feed into each other beautifully.

Christian Kost@kostchristian.bsky.social · 3w ago

Very happy that our paper Obligate cross-feeding of metabolites is common in soil microbial communities just came out in Nature Microbiology. See here 👇 Paywalled version: www.nature.com/articles/s41... Free read-only version: rdcu.be/fBHAb

🧵 New paper out in Nature Communications! 🐜🦠 How can an ancient nutritional symbiosis persist for millions of years, yet still be lost without killing its host? In Cardiocondyla ants, the answer appears to be remarkable metabolic flexibility. Paper: doi.org/10.1038/s414... 1/6

Metabolic plasticity supports a flexible nutritional symbiosis in Cardiocondyla ants - Nature Communications

Ancient symbioses may enable ants to thrive in diverse niches, but how these relationships are regulated remains unclear. This study reveals that some ants can dynamically regulate symbiont-derived be...

doi.org

Nice preprint from @lizscurious.bsky.social & lab on improvements to recovering bacterial isolates from urine, including fastidious taxa - also solves that thorny problem of when you can’t culture straightaway and need to ship/store samples #UTISky #UTI

bioRxiv Microbiology@biorxiv-microbiol.bsky.social · 3w ago

An expanded urine culturing workflow to cultivate and characterize diverse urobiome isolates https://www.biorxiv.org/content/10.64898/2026.08.24.746228v1