Unveiling the prokaryotic diversity and multipartite symbiotic relationships in the termite gut microbiota
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Date
2025-10-21
Publisher
Philipps-Universität Marburg
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Abstract
The gut of termites is a complex ecosystem that hosts diverse prokaryotic communities.
Many Bacteria and Archaea within this ecosystem engage in ancient symbiotic relationships
with cellulolytic flagellates, which are essential for lignocellulose digestion and take part in
intricate metabolic interactions. Due to difficulties cultivating these microbes, my doctoral
research focused on culture-independent approaches, including deep sequencing of gut
sections and flagellate suspensions, as well as metagenomic studies and fluorescence in situ
hybridization (FISH).
I developed the latest version of the Dictyopteran gut microbiota reference Database
(DictDb), which serves as an updated 16S rRNA gene reference for automated classification
of 16S amplicons. Key findings from this research include a taxonomic revision of
methanogenic Archaea colonizing arthropod guts, the analysis of the diversity and host
colonization patterns of filamentous Lachnospiraceae (Arthromitus), and improved
classification of termite-specific lineages. Notable taxa identified and expanded upon include
the primarily flagellate-associated Azobacteroidaceae (Bacteroidota), the highly diverse
homoacetogenic Breznakiellaceae (Spirochaetota), the cellulolytic Fibromonas
(Fibrobacterota), the rare Elusimicrobium (Elusimicrobiota), the termite-specific
Bifidobacteriaceae (Actinomycetota), and the putative energy parasites of the Opitutales
(Verrucomicrobiota).
Among the termite gut metagenome-assembled genomes (MAGs) recovered in a recent
study, I identified four new genera within the family Bifidobacteriaceae: Ancillula,
Opitulatrix, Servula, and Nutricula, expanding on the first report of protist-associated
Actinomycetota. The new species exhibit diverse biosynthetic capabilities. Members of
Opitulatrix have largely lost the ability to produce amino acids and cofactors, relying on
nutrients from their flagellate hosts, while Ancillula retains significant biosynthetic capacity.
Most termite-specific Bifidobacteriaceae retain an export system for threonine and serine
(ThrE), providing evidence of nutrient exchange with their flagellate hosts. Furthermore, the
observed genome erosion in this clade is balanced by horizontal gene transfer events within
the termite gut microbiota, supporting the hypothesis of convergent evolution among termite
gut flagellate symbionts.
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Metadata
Contributors
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Dates
Created: 2024Issued: 2025-10-21Updated: 2025-10-21
Faculty
Fachbereich Biologie
Language
eng
Data types
DoctoralThesis
DDC-Numbers
570
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Kästle Silva, Joana Maria (0009-0009-4070-5551): Unveiling the prokaryotic diversity and multipartite symbiotic relationships in the termite gut microbiota. : Philipps-Universität Marburg 2025-10-21. DOI: https://doi.org/10.17192/z2025.0057.