Fibrobacteres

Fibrobacterota is a small bacterial phylum which includes many of the major rumen bacteria, allowing for the degradation of plant-based cellulose in ruminant animals. Members of this phylum were categorized in other phyla. The genus '' Fibrobacter'' (the only genus of Fibrobacterota) was removed from the genus ''Bacteroides'' in 1988.

Phylogeny and comparative genomic studies

Although ''Fibrobacterota'' is currently recognized as a distinct phylum, phylogenetic studies based RpoC and Gyrase B protein sequences, indicate that ''Fibrobacter succinogenes'' is closely related to the species from the phyla ''Bacteroidetes'' and ''Chlorobi''. The species from these three phyla also branch in the same position based upon conserved signature indels in a number of important proteins. Lastly and most importantly, comparative genomic studies have identified two conserved signature indels (a 5-7 amino acid insert in the RpoC protein and a 13-16 amino acid insertion in serine hydroxymethyltransferase) and one signature protein (PG00081) that are uniquely shared by all of the species from these three phyla. All of these results provide compelling evidence that the species from these three phyla shared a common ancestor exclusive of all other bacteria and it has been proposed that they should all recognized as part of a single “FCB”superphylum.

Phylogeny

Phylogeny of Fibrobacterota.

Taxonomy

The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LSPN) and the National Center for Biotechnology Information (NCBI).

* Class Chitinispirillia Sorokin et al. 2016
** Order Chitinispirillales Sorokin et al. 2016]
*** Family Chitinispirillaceae Sorokin et al. 2016
**** Genus '' Chitinispirillum'' Sorokin et al. 2016
***** Species '' C. alkaliphilum'' Sorokin et al. 2016
* Class Chitinivibrionia Sorokin et al. 2014
** Order Chitinivibrionales Sorokin et al. 2014
*** Family Chitinivibrionaceae Sorokin et al. 2014
**** Genus '' Chitinivibrio'' Sorokin et al. 2014
***** Species '' C. alkaliphilus'' Sorokin et al. 2014
* Class Fibrobacteria Spain et al. 2012
** Order Fibrobacterales Spain et al. 2012 Abdul Rahman et al. 2016">Fibromonadales" Abdul Rahman et al. 2016*** Family Fibrobacteraceae Spain et al. 2012 Abdul Rahman et al. 2016">ibromonadaceae" Abdul Rahman et al. 2016**** Genus '' Fibrobacter'' Montgomery et al. 1988
***** Species '' F. intestinalis'' Montgomery et al. 1988
***** Species '' F. succinogenes'' (Hungate 1950) Montgomery et al. 1988
****** Subspecies '' F. s. elongatus'' Montgomery et al. 1988
****** Subspecies '' F. s. succinogenes'' (Hungate 1950) Montgomery et al. 1988
**** Genus "''Candidatus'' Fibromonas" Abdul Rahman et al. 2016
***** Species "''Ca.'' F. termitidis" Abdul Rahman et al. 2016
**** Genus "'' Hallerella''" Wylensek et al. 2020
***** Species "'' H. porci''" Wylensek et al. 2021
***** Species "'' H. succinigenes''" Wylensek et al. 2020

Distribution

The phylum Fibrobacterota is considered to be closely related to the CFB ytophaga-Flavibacterium-Bacteroidota It contains the genus ''Fibrobacter'', which has strains present in the guts of many mammals including cattle and pigs. The two described species in this genus namely, '' Fibrobacter succinogenes'' and '' Fibrobacter intestinalis'' are important members of fibrolytic communities in mammalian guts and have received a lot of attention in recent decades due to the long-standing interest microbes capable of degrading plant fiber.

Molecular evidence based on the amplification of 16rRNA genes from various environments suggest that the phylum is much more widespread than previously thought.

Most of the clones from mammalian environments group along with the known isolates in what has been called subphylum 1. Members of subphylum 2 however, have so far been found only in the gut of termites. and in some litter-feeding cockroaches. The predominance of subphylum 2 in cellulolytic fibre-associated bacterial communities in hindguts of wood-feeding Nasutitermes corniger suggests that they play an important role in the breakdown of plant material in higher termites.

See also

* '' Fibrobacter succinogenes''
* Candidate phylum TG3
* List of bacterial orders
* List of bacteria genera

References

*

External links

* ''List of Prokaryotic Names with Standing in Nomenclature''
Genus ''Fibrobacter''
* Systema Naturae 2000 Classification: Phylu

{{Taxonbar, from=Q1200941
Bacteria phyla