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bioRxiv · 10.1101/2025.10.11.681818

An extremophilic Nocardiopsis strain from Great Salt Lake expands the taxonomic range of mycolic acid biosynthesis

Scott, A. F.·Jin, T.·Bring Horvath, E. R.·Krull, N. K.·Iizumi, R.·Bender, A.·Murphy, B. T.·Fenical, W.·Winter, J.
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Abstract

Mycolic acids, long-chain fatty acids that form the characteristic and relatively impermeable mycomembrane, have long been considered a defining chemotaxonomic feature of the order Mycobacteriales. Here, we report that Nocardiopsis bonnevillensis, a new type strain isolated from the hypersaline environment of Great Salt Lake, is the first organism outside of this order known to produce mycolic acids. Lipid profiling, acid-fast staining, isoniazid sensitivity, and genome mining confirmed hallmark features of mycolic acid biosynthesis. Evaluation of the strains metabolic capabilities led to the isolation of bonnevanoside, a thiophenyl nonulopyranoside reported here for the first time from a natural source. Moreover, additional Great Salt Lake-derived Nocardiopsis isolates exhibited acid-fast staining, suggesting that this trait may be more widespread than previously recognized. Altogether, these findings expand the taxonomic distribution of mycolic acid biosynthesis, challenge long-standing chemotaxonomic boundaries, and highlight the potential ecological significance of mycolate-containing envelopes in supporting bacterial survival in extreme environments.

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Scott, A. F., Jin, T., Bring Horvath, E. R., Krull, N. K., Iizumi, R., Bender, A., Murphy, B. T., Fenical, W., Winter, J.. 2025-10-12. An extremophilic Nocardiopsis strain from Great Salt Lake expands the taxonomic range of mycolic acid biosynthesis. https://doi.org/10.1101/2025.10.11.681818

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