The Ubiquitous Soil Terpene Geosmin Acts as a Warning Chemical

Abstract

One of the key chemicals that give soil its earthy aroma, geosmin is a frequent water contaminant produced by a range of unrelated microbes. Many animals, including humans, are able to detect geosmin at minute concentrations, but the benefit that this compound provides to its producing organisms is poorly understood.

Comparative genomics of Myxococcus and Pyxidicoccus, including the description of four novel species: Myxococcus guangdongensis sp. nov., Myxococcus qinghaiensis sp. nov., Myxococcus dinghuensis sp. nov., and Pyxidicoccus xibeiensis sp. nov.

“…Geosmin has been found in various strains of cyanobacteria, streptomyces, and myxobacteria, which is considered a major cause of most taste and odor episodes in drinking water ( Wang Z. J. et al, 2019 ). Recently, geosmin has been found to appear to act as a warning signal indicating the unpalatability of its producers and reducing predation in a manner that benefits predator and prey ( Zaroubi et al, 2022 ). Different CAZymes and secondary metabolites produced by the genera Myxococcus and Pyxidicoccus may to a certain extent reflect their predation efficiencies against various bacteria and fungi.…”

Saccharopolyspora sp. NFXS83 in Marine Biotechnological Applications: From Microalgae Growth Promotion to the Production of Secondary Metabolites

“…Other secondary metabolites gene clusters were also detected, such as those involved in terpene production, including geosmin, which is a known volatile of actinomycetes [54,55], and an unknown carotenoid pigment (isorenieratene-like), as well as a gene cluster containing the ectoine production genes. These secondary metabolites may play key important roles in the ecological adaptations of Saccharopolyspora sp.…”

Concepts and conjectures concerning predatory performance of myxobacteria

“…These observations present an alternative role of specialized metabolites during predator competition for nutrients. Production of the ubiquitous, volatile terpene geosmin by M. xanthus during exponential growth serves as a warning signal to dissuade the bacteriophagous nematode Caenorhabditis elegans ( Zaroubi et al, 2022 ; Figure 1B ). The geosmin BGC is also present in genomes from nearly every sequenced myxobacteria as well as many other natural product-producing bacteria ( Gregory et al, 2019 ).…”

“…(A) Metabolites and metabolic transformations that benefit predation of prey ( Xiao et al, 2011 ; Muller et al, 2016 ; Sutton et al, 2019 ; Akbar et al, 2022 ). (B) Myxobacterial metabolites not directly involved in predation of prey ( Marcos-Torres et al, 2020 ; Zaroubi et al, 2022 ). (C) Prey metabolites and metabolic transformations that inhibit myxobacterial predation ( Bull et al, 2002 ; Muller et al, 2014 ; Sutton et al, 2019 ; Wang et al, 2019 ).…”