Thermophilic Dehalococcoidia with unusual traits shed light on an unexpected past.
Marike PalmerJonathan K CovingtonEn-Min ZhouScott C ThomasNeeli HabibCale O SeymourDengxun LaiJuliet JohnstonAmeena HashimiJian-Yu JiaoAlise R MuokLan LiuWen-Dong XianXiao-Yang ZhiMeng-Meng LiLeslie P SilvaBenjamin P BowenKatherine LouieAriane BriegelJennifer Pett-RidgePeter K WeberElitza I TochevaTanja WoykeTrent R NorthenXavier MayaliWen-Jun LiBrian P HedlundPublished in: The ISME journal (2023)
Although the phylum Chloroflexota is ubiquitous, its biology and evolution are poorly understood due to limited cultivability. Here, we isolated two motile, thermophilic bacteria from hot spring sediments belonging to the genus Tepidiforma and class Dehalococcoidia within the phylum Chloroflexota. A combination of cryo-electron tomography, exometabolomics, and cultivation experiments using stable isotopes of carbon revealed three unusual traits: flagellar motility, a peptidoglycan-containing cell envelope, and heterotrophic activity on aromatics and plant-associated compounds. Outside of this genus, flagellar motility has not been observed in Chloroflexota, and peptidoglycan-containing cell envelopes have not been described in Dehalococcoidia. Although these traits are unusual among cultivated Chloroflexota and Dehalococcoidia, ancestral character state reconstructions showed flagellar motility and peptidoglycan-containing cell envelopes were ancestral within the Dehalococcoidia, and subsequently lost prior to a major adaptive radiation of Dehalococcoidia into marine environments. However, despite the predominantly vertical evolutionary histories of flagellar motility and peptidoglycan biosynthesis, the evolution of enzymes for degradation of aromatics and plant-associated compounds was predominantly horizontal and complex. Together, the presence of these unusual traits in Dehalococcoidia and their evolutionary histories raise new questions about the timing and selective forces driving their successful niche expansion into global oceans.
Keyphrases
- cell wall
- genome wide
- single cell
- biofilm formation
- cell therapy
- dna methylation
- bacillus subtilis
- staphylococcus aureus
- magnetic resonance imaging
- mesenchymal stem cells
- high resolution
- type iii
- gene expression
- pseudomonas aeruginosa
- cystic fibrosis
- magnetic resonance
- mass spectrometry
- electron microscopy
- candida albicans