Sixty-One Volatiles Have Phylogenetic Signals Across Bacterial Domain and Fungal Kingdom

Abstract

Microorganisms are diverse in their genome sequences and subsequently in their encoded metabolic pathways, which enabled them to adapt to numerous environmental conditions. They produce thousands of small molecules, many of which are volatiles in nature and play important roles in signaling in intra-and inter-species to kingdom and domain interactions, survival, or virulence. Many of these compounds have been studied, characterized, and organized in the mVOC 2.0 database. However, such dataset has not been investigated comprehensively in terms of its phylogeny to determine key volatile markers for certain taxa. It was hypothesized that some of the volatiles described in the mVOC 2.0 database could function as a phylogenetic signal since their production is conserved among certain taxa within the microbial evolutionary tree. Our meta-analysis revealed that some volatiles were produced by a large number of bacteria but not in fungal genera such as dimethyl disulfide, acetic acid, 2-nonanone, dimethyl trisulfide, 2-undecanone, isovaleric acid, 2-tridecanone, propanoic acid, and indole (common bacterial compounds). In contrast, 1-octen-3-ol, 3-octanone, and 2-pentylfuran (common fungal compounds) were produced primarily by fungal genera. Such chemical information was further confirmed by investigating genomic data of publicly available databases revealing that bacteria or fungi harbor gene families involved in these volatiles' biosynthesis. Our phylogenetic signal testing identified 61 volatiles with a significant phylogenetic signal as demonstrated by phylogenetic D statistic P-value < 0.05. Thirty-three volatiles were phylogenetically conserved in the bacterial domain (e.g., cyclocitral) compared to 17 volatiles phylogenetically conserved in the fungal kingdom (e.g., aristolochene), whereas 11 volatiles were phylogenetically conserved in genera from both bacteria and fungi (e.g., geosmin). These volatiles belong to different chemical classes such as heterocyclic compounds, long-chain fatty acids, sesquiterpenoids, and aromatics. The performed approaches serve as a starting point to investigate less explored volatiles with potential roles in signaling, antimicrobial therapy, or diagnostics.

Physicochemical property, bacterial diversity, and volatile profile during ripening of naturally fermented dry mutton sausage produced from Jianzhou big-eared goat

“…1-octen-3ol is a characteristic fragrance compound produced by Aspergillus, such as Aspergillus luchuensis (Kataoka et al, 2020), Aspergillus flavus (Miyamoto et al, 2014), and so on. Moreover, 2-pentylfuran was commonly known and definitely confirmed to be produced primarily by fungal genera in the report of Elmassry et al (2020). Therefore, it could be inferred that certain amounts of fungi might be existing in our mutton sausage.…”

Antibiotic Effects of Volatiles Produced by Bacillus tequilensis XK29 against the Black Spot Disease Caused by Ceratocystis fimbriata in Postharvest Sweet Potato

“…Isovaleric acid, isobutyric acid, and 2-methylbutanoic acid are short-chain fatty acids. Isovaleric acid is usually produced by a large number of bacteria rather than fungi . Researchers found that isovaleric acid not only inhibited the mycelial growth of Fusarium oxysporum and Moniliophthora perniciosa but also inhibited the biofilm formation of Staphylococcus epidermidis by reducing polysaccharide synthesis. , Isobutyric acid, the main volatile component of the first commercial microbial fumigant, Muscodor albus, is usually monitored as an indicator of antifungal activity .…”

Acetic Acid Acting as a Signal Molecule in Quorum Sensing System Enhances Production of 2,3-Butanediol in Saccharomyces Cerevisiae

“…In other words, it is beneficial to the production of 2,3-BD under acidic conditions, consequently indicating that acetic acid exerts an indispensable role in the entire production process of 2,3-BD. At the same time, studies have been shown that acetic acid can be used as a signal molecule to affect cell membranes, bacteriocins and QS (Elmassry et al 2020;Ge et al 2019). Therefore, it can also be believed that in the S. cerevisiae quorum sensing system, acetic acid has the potential as a signal molecule.…”