PT Unknown
AU Schalk, F
TI Functional and genomic analysis of bacterial and fungal natural products derived from the fungus-growing termite
PY 2023
WP https://www.db-thueringen.de/receive/dbt_mods_00057489
LA en
DE Termitomyces •	Pseudoxylaria •	Termite •	Natural Products •	Biomass Degradation •	Symbiosis •	Fungus Comb •	Pseudoxylaramide •	Xylasporin •	Xylacremolide •	Co-Cultivation •	Mass Spectrometry •	Structure Elucidation •	Bacteria •	Fungi •	Bioactivity
AB In frame of this thesis, the function and role of natural products produced by microorganisms found within the fungus-farming termite system was investigated. The focus was set on three key aspects: Oxidative plant matter degradation by the fungal mutualist Termitomyces, exploration of natural products produced by the fungal antagonist Pseudoxylaria and its ecological role, as well as investigations into the defensive role of co-occurring bacteria against invaders. The findings presented within this thesis demonstrate, how well the plant matter degradation pathways utilized by Termitomyces are optimized for the unique conditions of the fungus comb and how its surprising lack of major white-rot enzymes is likely compensated for by the insect host, highlighting a successful integration of fungal biomass degradation into the symbiotic co-existence within the termite system. The herein presented studies also support previous findings, that antagonistic fungi of the subgenus Pseudoxylaria clearly form a genetically distinct group from their free-living Xylaria counterparts. In the context of this thesis, several novel natural products produced by Pseudoxylaria were successfully isolated and structurally characterized. In total, structure elucidation efforts resulted in the discovery of four new linear tetrapeptides (pseudoxylaramides), four novel depsipeptides (xylacremolides) and two novel cytosporin derivatives (xylasporins). Investigations into two Actinobacteria previously isolated from fungus-farming termites confirmed how natural products produced by termite-associated microbes may represent a major line of defense in the termite microverse against invaders. Both Streptomyces sp. RB13 and Actinomadura sp. RB99 were found to display elevated antifungal activity against the antagonist while only moderately affecting growth of the fungal mutualist. Targeted investigations resulted in the isolation of four new madurastatin-like siderophores with antifungal properties.
PI Jena
ER