Fibrobacterota

{{Short description|Phylum of bacteria}} {{Automatic taxobox | taxon = Fibrobacterota | authority = Garrity & Holt 2021<ref>{{cite journal | vauthors = Oren A, Garrity GM | title = Valid publication of the names of forty-two phyla of prokaryotes | journal = Int J Syst Evol Microbiol | year = 2021 | volume = 71 | issue = 10 | pages = 5056 | doi = 10.1099/ijsem.0.005056 | pmid = 34694987 | s2cid = 239887308 | doi-access = free }}</ref> | subdivision_ranks = Classes | subdivision = * Chitinispirillia * Chitinivibrionia * Fibrobacteria | synonyms = * "Fibrobacteraeota" Oren et al. 2015 * "Fibrobacteres" Garrity and Holt 2001 * "Fibrobacterota" Whitman et al. 2018 * "Raymondbacteria" Anantharaman et al. 2016 }}

'''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'' was removed from the genus ''Bacteroides'' in 1988.<ref>{{cite journal |vauthors=Montgomery L, Flesher B, Stahl D | title = Transfer of ''Bacteroides succinogenes'' (Hungate) to ''Fibrobacter'' gen. nov. as ''Fibrobacter succinogenes'' comb. nov. and description of ''Fibrobacter intestinalis'' sp. nov | journal = Int. J. Syst. Bacteriol. | year = 1988 | volume = 38 | issue = 4| pages = 430–435 | doi = 10.1099/00207713-38-4-430 | doi-access = free }}</ref>

== 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''.<ref name="Gupta">{{cite journal | last1 = Gupta | first1 = R. S. | year = 2004 | title = The phylogeny and signature sequences characteristics of Fibrobacteres, Chlorobi, and Bacteroidetes | journal = Critical Reviews in Microbiology | volume = 30 | issue = 2| pages = 123–140 | doi = 10.1080/10408410490435133 | pmid=15239383| s2cid = 24565648 }}</ref> The species from these three phyla also branch in the same position based upon conserved signature indels in a number of important proteins.<ref>{{cite journal | last1 = Griffiths | first1 = E | last2 = Gupta | first2 = RS | year = 2001 | title = The use of signature sequences in different proteins to determine the relative branching order of bacterial divisions: evidence that Fibrobacter diverged at a similar time to Chlamydia and the Cytophaga- Flavobacterium-Bacteroides division | journal = Microbiology | volume = 147 | issue = 9| pages = 2611–22 | doi=10.1099/00221287-147-9-2611 | pmid=11535801| doi-access = free }}</ref> 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.<ref name="GuptaB">{{cite journal | last1 = Gupta | first1 = R. S. | last2 = Lorenzini | first2 = E. | year = 2007 | title = Phylogeny and molecular signatures (conserved proteins and indels) that are specific for the Bacteroidetes and Chlorobi species | journal = BMC Evolutionary Biology | volume = 7 | page = 71 | doi = 10.1186/1471-2148-7-71 | pmid=17488508 | pmc=1887533 | doi-access = free }}</ref> 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.<ref name="Gupta"/><ref name="GuptaB" />

==Phylogeny== Phylogeny of Fibrobacterota. {| class="wikitable" |- ! colspan=1 | 16S rRNA based LTP_10_2024<ref>{{cite web|title=The LTP |url=https://imedea.uib-csic.es/mmg/ltp/#LTP| access-date=10 December 2024}}</ref><ref>{{cite web|title=LTP_all tree in newick format| url=https://imedea.uib-csic.es/mmg/ltp/wp-content/uploads/ltp/LTP_all_10_2024.ntree |access-date=10 December 2024}}</ref><ref>{{cite web|title=LTP_10_2024 Release Notes| url=https://imedea.uib-csic.es/mmg/ltp/wp-content/uploads/ltp/LTP_10_2024_release_notes.pdf |access-date=10 December 2024}}</ref> ! colspan=1 | 120 marker proteins based GTDB 09-RS220<ref name="about">{{cite web |title=GTDB release 09-RS220 |url=https://gtdb.ecogenomic.org/about#4%7C |website=Genome Taxonomy Database|access-date=10 May 2024}}</ref><ref name="tree">{{cite web |title=bac120_r220.sp_labels |url=https://data.gtdb.ecogenomic.org/releases/release220/220.0/auxillary_files/bac120_r220.sp_labels.tree |website=Genome Taxonomy Database|access-date=10 May 2024}}</ref><ref name="taxon_history">{{cite web |title=Taxon History |url=https://gtdb.ecogenomic.org/taxon_history/ |website=Genome Taxonomy Database|access-date=10 May 2024}}</ref> |- | style="vertical-align:top| {{Clade | style=font-size:90%;line-height:90% |1={{clade |1={{clade |label1=Chitinivibrionia |1={{clade |label1=Chitinivibrionales |1={{clade |label1=Chitinivibrionaceae |1=''Chitinivibrio alkaliphilus'' }} }} |label2=Chitinispirillia |2={{clade |label1=Chitinispirillales |1={{clade |label1=Chitinispirillaceae |1=''Chitinispirillum alkaliphilum'' }} }} }} |2={{clade |label1=Fibrobacteria |1={{clade |label1=Fibrobacterales |sublabel1=Fibrobacteraceae |1={{clade |label1=''Fibrobacter succinogenes'' |1={{clade |1=''F. s. elongatus'' |2=''F. s. succinogenes'' }} |label2=''Hallerella'' |2={{clade |1=''H. porci'' |2={{clade |1=''H. succinigenes'' |2=''Fibrobacter intestinalis'' }} }} }} }} }} }} }} | {{Clade | style=font-size:90%;line-height:90% |1={{clade |1={{clade |label1=Chitinivibrionia |1={{clade |label1=Chitinivibrionales |1={{clade |label1=Chitinispirillaceae |1=''Chitinispirillum alkaliphilum'' |label2=Chitinivibrionaceae |2=''Chitinivibrio alkaliphilus'' }} }} }} |2={{clade |1="Raymondbacteria" (RIF7) |2={{clade |label1=Fibrobacteria |1={{clade |label1=Fibrobacterales |sublabel1=Fibrobacteraceae |1={{clade |1="''Ca.'' Fibromonas termitidis" |2={{clade |label1=''Fibrobacter'' |1={{clade |1=''F. succinogenes elongatus'' |2=''F. succinogenes'' }} |label2=''Hallerella'' |2={{clade |1=''H. succinigenes'' |2={{clade |1=''H. porci'' |2=''Fibrobacter intestinalis'' }} }} }} }} }} }} }} }} }} |}

==Taxonomy== The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LSPN)<ref name=LPSN>{{lpsn3|phylum/fibrobacterota|Fibrobacterota}}</ref> and National Center for Biotechnology Information (NCBI).<ref name=NCBI>{{cite web |author=Schoch CL |display-authors=et al. |url=https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?command=show&mode=tree&id=65842&lvl=3 |title=Fibrobacterota |accessdate=2025-06-05 |publisher=National Center for Biotechnology Information (NCBI) taxonomy database}}</ref> right|thumb|phylum ''Fibrobacterota'' and some of its phylogenetic neighbours

* '''Class Chitinispirillia''' Sorokin et al. 2016 ** '''Order Chitinispirillales''' Sorokin et al. 2016] *** '''Family Chitinispirillaceae''' Sorokin et al. 2016 **** Genus "''Cellulosispirillum''" Sorokin, Merkel & Khizhniak 2025 ***** Species "''C. alkaliphilum''" Sorokin, Merkel & Khizhniak 2025 **** 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 ["Fibromonadales" Abdul Rahman et al. 2016] *** '''Family Fibrobacteraceae''' Spain et al. 2012 [Fibromonadaceae" 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 [Cytophaga-Flavibacterium-Bacteroidota].<ref name="GuptaB"/> It contains the genus ''Fibrobacter'', which has strains present in the guts of many mammals including cattle and pigs.<ref>{{cite journal | title = Novel molecular features of the fibrolytic intestinal bacterium ''Fibrobacter intestinalis'' not shared with ''Fibrobacter succinogenes'' as determined by suppressive subtractive hybridization |author1=Qi, M. |author2=Nelson, K.E. |author3=Daugherty, S.C. |author4=Nelson, W.C. |author5=Hance, I.R. |author6=Morrison, M. |author7=Forsberg, C.W. | journal = Journal of Bacteriology | volume = 187 | issue = 11 | pages = 3739–3751 | year = 2005 |doi=10.1128/jb.187.11.3739-3751.2005 |pmid=15901698 |pmc=1112041}} </ref> 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.<ref>{{cite journal | title = Detection of novel ''Fibrobacter populations'' in landfill sites and determination of their relative abundance via quantitative PCR | journal = Environmental Microbiology | volume = 10 | issue = 5 | pages= 1310–1319 | year= 2008 |doi=10.1111/j.1462-2920.2007.01544.x |pmid=18266756 | last1 = McDonald | first1 = JE | last2 = Lockhart | first2 = RJ | last3 = Cox | first3 = MJ | last4 = Allison | first4 = HE | last5 = McCarthy | first5 = AJ}} </ref><ref name=Hongoh2006> {{cite journal | title= Phylogenetic diversity, localization, and cell morphologies of members of the candidate phylum TG3 and a subphylum in the phylum ''Fibrobacteres'', recently discovered bacterial groups dominant in termite guts |author1=Hongoh, Y. |author2=Deevong, P. |author3=Hattori, S. |author4=Inoue, T. |author5=Noda, S. |author6=Noparatnaraporn, N. |author7=Kudo, T. |author8=Ohkuma, M. | journal= Applied and Environmental Microbiology | volume= 72 | issue= 10 | pages= 6780–6788 | year= 2006 |doi=10.1128/aem.00891-06 |pmid=17021231 |pmc=1610327 | bibcode= 2006ApEnM..72.6780H}} </ref> Most of the clones from mammalian environments group along with the known isolates in what has been called subphylum 1.<ref name = Hongoh2006 /> Members of subphylum 2 however, have so far been found only in the gut of termites.<ref name = Hongoh2006 /><ref>{{cite journal | last1 = Mikaelyan | first1 = A. | last2 = Dietrich | first2 = C. | last3 = Köhler | first3 = T. | last4 = Poulsen | first4 = M. | last5 = Sillam-Dussès | first5 = D. | last6 = Brune | first6 = A.| year = 2015 | title = Diet is the primary determinant of bacterial community structure in the guts of higher termites | journal = Molecular Ecology | volume = 24 | issue = 20| pages = 5824–5895 | doi = 10.1111/mec.13376 | pmid=26348261| s2cid = 206182668 }}</ref> and in some litter-feeding cockroaches.<ref>{{cite journal | last1 = Mikaelyan | first1 = A. | last2 = Köhler | first2 = T. | last3 = Lampert| first3 = N. | last4 = Rohland| first4 = J.| last5 = Boga| first5 = H.| last6 = Meuser| first6 = K.| last7 = Brune| first7 = A.| year = 2015 | title = Classifying the bacterial gut microbiota of termites and cockroaches: A curated phylogenetic reference database (DictDb) | journal = Systematic and Applied Microbiology | volume = 38 | issue = 7 | pages = 472–482 | doi = 10.1016/j.syapm.2015.07.004 | pmid=26283320}}</ref> 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.<ref>{{cite journal | last1 = Mikaelyan | first1 = A. | last2 = Strassert | first2 = J. | last3 = Tokuda | first3 = G. | last4 = Brune | first4 = A.| year = 2014 | title = The fibre-associated cellulolytic bacterial community in the hindgut of wood-feeding higher termites (Nasutitermes spp.) | journal = Environmental Microbiology | volume = 16 | issue = 9| pages = 2711–2722 | doi = 10.1111/1462-2920.12425 }}</ref>

==References== <references/>

* {{cite book | editor = Holt JG | title = Bergey's Manual of Determinative Bacteriology | edition = 9th | publisher = Williams & Wilkins | year = 1994 | isbn = 978-0-683-00603-2 }}

==External links== * ''List of Prokaryotic Names with Standing in Nomenclature'' - [https://lpsn.dsmz.de/genus/fibrobacter Genus ''Fibrobacter''] * Systema Naturae 2000 Classification: Phylum [http://sn2000.taxonomy.nl/Main/Classification/109014.htm Fibrobacteres] {{Webarchive|url=https://web.archive.org/web/20060314013828/http://sn2000.taxonomy.nl/Main/Classification/109014.htm |date=2006-03-14 }}

{{Bacteria classification|state=collapsed}} {{Life on Earth}} {{Taxonbar|from=Q1200941}} Category:Bacteria phyla Category:Fibrobacterota