{{Short description|Genus of bacteria}} {{Automatic taxobox | taxon = Heyndrickxia | authority = Gupta et al. 2020<ref name=LPSN/> | type_species = ''Heyndrickxia oleronia'' | type_species_authority = (Kuhnigk et al. 1996) Gupta et al. 2020 | subdivision_ranks = Species | subdivision_ref = <ref name=NCBI/> | subdivision = * ''H. acidicola'' * ''H. oleronia'' * ''H. sporothermodurans'' * ''H. vini'' }}
'''''Heyndrickxia''''' is a genus of gram-positive rod-shaped bacteria (except for ''Heyndrickxia'' ''sporothermodurans'', which stains gram-negative) in the family ''Bacillaceae'' within the order ''Bacillales''.<ref name=":13">{{Cite journal|last1=Gupta|first1=Radhey S.|last2=Patel|first2=Sudip|last3=Saini|first3=Navneet|last4=Chen|first4=Shu|date=2020-11-01|title=Robust demarcation of 17 distinct Bacillus species clades, proposed as novel Bacillaceae genera, by phylogenomics and comparative genomic analyses: description of Robertmurraya kyonggiensis sp. nov. and proposal for an emended genus Bacillus limiting it only to the members of the Subtilis and Cereus clades of species|journal=International Journal of Systematic and Evolutionary Microbiology|language=en|volume=70|issue=11|pages=5753–5798|doi=10.1099/ijsem.0.004475|issn=1466-5026|pmid=33112222|doi-access=free}}</ref><ref>{{Cite book|date=2005|editor-last=Brenner|editor-first=Don J.|editor2-last=Krieg|editor2-first=Noel R.|editor3-last=Staley|editor3-first=James T.|editor4-last=Garrity|editor4-first=George M.|editor5-last=Boone|editor5-first=David R.|editor6-last=De Vos|editor6-first=Paul|editor7-last=Goodfellow|editor7-first=Michael|editor8-last=Rainey|editor8-first=Fred A.|editor9-last=Schleifer|editor9-first=Karl-Heinz|title=Bergey's Manual® of Systematic Bacteriology|url=http://dx.doi.org/10.1007/0-387-28022-7|doi=10.1007/0-387-28022-7|isbn=978-0-387-24144-9}}</ref> The type species for this genus is ''Heyndrickxia oleronia.''<ref name=LPSN/>
Members of ''Heyndrickxia'' were originally assigned to the genus ''Bacillus.'' The polyphyletic nature and unclear evolutionary relationships of the genus ''Bacillus'' has long been a topic in the scientific community.<ref>{{Cite journal|last=Logan|first=N.A.|date=2011-12-20|title=Bacillus and relatives in foodborne illness|journal=Journal of Applied Microbiology|volume=112|issue=3|pages=417–429|doi=10.1111/j.1365-2672.2011.05204.x|issn=1364-5072|pmid=22121830|doi-access=free}}</ref><ref>{{Cite journal|last1=La Duc|first1=Myron T|last2=Satomi|first2=Masataka|last3=Agata|first3=Norio|last4=Venkateswaran|first4=Kasthuri|date=March 2004|title=gyrB as a phylogenetic discriminator for members of the Bacillus anthracis–cereus–thuringiensis group|url=http://dx.doi.org/10.1016/j.mimet.2003.11.004|journal=Journal of Microbiological Methods|volume=56|issue=3|pages=383–394|doi=10.1016/j.mimet.2003.11.004|issn=0167-7012|pmid=14967230|url-access=subscription}}</ref> It was composed of many unrelated species with a diverse range of biochemical characteristics due to the vague criteria (such as the ability to form endospores under aerobic conditions) used to assign species to this genus.<ref>{{Cite journal|last1=Ash|first1=Carol|last2=Farrow|first2=J.A.E.|last3=Wallbanks|first3=Sally|last4=Collins|first4=M.D.|date=2008-06-28|title=Phylogenetic heterogeneity of the genus Bacillus revealed by comparative analysis of small-subunit-ribosomal RNA sequences|url=http://dx.doi.org/10.1111/j.1472-765x.1991.tb00608.x|journal=Letters in Applied Microbiology|volume=13|issue=4|pages=202–206|doi=10.1111/j.1472-765x.1991.tb00608.x|s2cid=82988953|issn=0266-8254|url-access=subscription}}</ref> Multiple phylogenetic studies and comparative genomic analyses have been conducted to clarify the taxonomy of genus, resulting in the restriction of ''Bacillus'' to only include species closely related to ''Bacillus subtilis'' and ''Bacillus cereus'',<ref name=":03">{{Cite journal|last1=Patel|first1=Sudip|last2=Gupta|first2=Radhey S.|date=2020-01-01|title=A phylogenomic and comparative genomic framework for resolving the polyphyly of the genus Bacillus: Proposal for six new genera of Bacillus species, Peribacillus gen. nov., Cytobacillus gen. nov., Mesobacillus gen. nov., Neobacillus gen. nov., Metabacillus gen. nov. and Alkalihalobacillus gen. nov.|journal=International Journal of Systematic and Evolutionary Microbiology|language=en|volume=70|issue=1|pages=406–438|doi=10.1099/ijsem.0.003775|issn=1466-5026|pmid=31617837|doi-access=free}}</ref><ref name=":13" /> and the establishment of many novel genera such as ''Virgibacillus, Solibacillus, Brevibacillus'' and ''Ectobacillus''.<ref>{{Cite journal|last1=Heyndrickx|first1=M.|last2=Lebbe|first2=L.|last3=Kersters|first3=K.|last4=Hoste|first4=B.|last5=De Wachter|first5=R.|last6=De Vos|first6=P.|last7=Forsyth|first7=G.|last8=Logan|first8=N. A.|date=1999-07-01|title=Proposal of Virgibacillus proomii sp. nov. and emended description of Virgibacillus pantothenticus (Proom and Knight 1950) Heyndrickx et al. 1998|journal=International Journal of Systematic and Evolutionary Microbiology|volume=49|issue=3|pages=1083–1090|doi=10.1099/00207713-49-3-1083|issn=1466-5026|pmid=10425765|doi-access=free}}</ref><ref>{{Cite journal|last1=Shida|first1=O.|last2=Takagi|first2=H.|last3=Kadowaki|first3=K.|last4=Komagata|first4=K.|date=1996-10-01|title=Proposal for Two New Genera, Brevibacillus gen. nov. and Aneurinibacillus gen. nov.|journal=International Journal of Systematic Bacteriology|language=en|volume=46|issue=4|pages=939–946|doi=10.1099/00207713-46-4-939|issn=0020-7713|pmid=8863420|doi-access=free}}</ref><ref>{{Cite journal|last1=Mual|first1=Poonam|last2=Singh|first2=Nitin Kumar|last3=Verma|first3=Ashish|last4=Schumann|first4=Peter|last5=Krishnamurthi|first5=Srinivasan|last6=Dastager|first6=Syed|last7=Mayilraj|first7=Shanmugam|date=2016-05-01|title=Reclassification of Bacillus isronensis Shivaji et al. 2009 as Solibacillus isronensis comb. nov. and emended description of genus Solibacillus Krishnamurthi et al. 2009|journal=International Journal of Systematic and Evolutionary Microbiology|language=en|volume=66|issue=5|pages=2113–2120|doi=10.1099/ijsem.0.000982|issn=1466-5026|pmid=26907585|doi-access=free}}</ref><ref name=":13" />
The name ''Heyndrickxia'' was chosen to celebrate Professor Marc Heyndrickx (University of Gent) for his contributions to the field of microbiology and his research on ''Bacillus'' species.<ref name=":13" />
== Biochemical characteristics and molecular signatures == Members of the genus ''Heyndrickxia'' are aerobic, endospore-forming bacteria. Most species are motile and generally catalase- and oxidase-positive. The main isolation source for this genus is in dairy or dairy production facilities, such as in raw milk and feed concentrate for cattle. ''Heyndrickxia'' can survive in temperatures ranging from {{Convert|20 to 55|C|F|abbr=|sp=us}}, but optimal growth occurs in the range of {{Convert|30-45|C|F|abbr=|sp=us}}.<ref name=":13" />
Five conserved signature indels (CSIs) have been identified as exclusive for this genus in the proteins stage V sporulation protein D, N-acetyl-gamma-glutamyl-phosphate reductase, type II/IV secretion system protein, homoserine O-succinyltransferase and septation ring formation regulator EzrA which can be used as reliable distinguishing molecular signatures to demarcate ''Heyndrickxia'' species from other ''Bacillaceae'' genera and bacteria.<ref name=":13" />
== Taxonomy == {{As of|2021|May}}, there are a total of 3 species with validly published names in the genus ''Heyndrickxia''.<ref name=LPSN>{{cite web |author=A.C. Parte |url=https://lpsn.dsmz.de/genus/heyndrickxia |title=Heyndrickxia |access-date=2025-02-28 |publisher=List of Prokaryotic names with Standing in Nomenclature (LPSN) |display-authors=et al.}}</ref><ref name=NCBI>{{cite web |author=C.L. Schoch |url=https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Tree&id=2837504&lvl=3&lin=f&keep=1&srchmode=1&unlock |title=Heyndrickxia |access-date=2025-02-28 |publisher=National Center for Biotechnology Information (NCBI) taxonomy database |display-authors=et al.}}</ref> Members of this genus form a monophyletic branch in various phylogenetic trees created based on concatenated sequences from various datasets of conserved proteins and 16S rRNA genome sequences.<ref name=":13" /> The monophyletic nature of this genus is also found in the Genome Taxonomy Database.<ref>{{Cite web|title=GTDB - Tree|url=https://gtdb.ecogenomic.org/tree?r=d__Bacteria|access-date=2021-05-25|website=gtdb.ecogenomic.org}}</ref>
Additionally, the non-validly published species "Bacillus obstructivis" also branches with members of ''Heyndrickxia'' as well as share the unique molecular markers specific for the genus.<ref name=":13" /> However, transfer of this species into the clade was not proposed due to the lack of culture strain information. This indicates the need to perform periodic analysis of the classification of this genus when more genome sequence and culture stain information becomes available.
In July 2023, an article in the ''IJSEM'' argued ''Bacillus acidicola'', ''Bacillus pervagus'', ''Margalitia'', and ''Weizmannia'' should all be subsumed under ''Heyndrickxia''. Being a taxonomic opinion in the IJSEM, the new combination names are considered valid.<ref name="Rao">{{cite journal |last1=Narsing Rao |first1=MP |last2=Banerjee |first2=A |last3=Liu |first3=GH |last4=Thamchaipenet |first4=A |title=Genome-based reclassification of Bacillus acidicola, Bacillus pervagus and the genera Heyndrickxia, Margalitia and Weizmannia. |journal=International Journal of Systematic and Evolutionary Microbiology |date=July 2023 |volume=73 |issue=7 |doi=10.1099/ijsem.0.005961 |pmid=37462355|doi-access=free}}</ref> GTDB release R214 does not yet include this "lumping" change.
==Phylogeny== {| 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:80% |1={{clade |1={{clade |1=''Margalitia shackletonii'' |2=''Weizmannia ginsengihumi'' }} |2={{clade |label1=''Heyndrickxia'' |1={{clade |1=''H. camelliae'' <small>(Niu et al. 2018) Narsing-Rao et al. 2023</small> |2={{clade |1=''H. acidicola'' <small>(Albert et al. 2005) Narsing-Rao et al. 2023</small> |2={{clade |1=''Oikeobacillus pervagus'' <small>(Kosowski et al. 2014) Narsing Rao et al. 2023</small> |2={{clade |1=''H. oleronia'' <small>(Kuhnigk et al. 1996) Gupta et al. 2020</small> |2={{clade |1=''H. sporothermodurans'' <small>(Pettersson et al. 1996) Gupta et al. 2020</small> |2=''H. vini'' <small>(Ma et al. 2017) Gupta et al. 2020</small> }} }} }} }} }} }} }} }} | {{Clade | style=font-size:90%;line-height:80% |1={{clade |1=''Weizmannia'' |2={{clade |1=''Heyndrickxia acidicola'' |2={{clade |label1=''Margalitia'' |1={{clade |1=''M. camelliae'' <small>(Niu et al. 2018) Gupta et al. 2020</small> |2=''M. shackletonii'' }} |label2=''Heyndrickxia'' |2={{clade |1=''H. oleronia'' |2={{clade |1=''H. sporothermodurans'' |2=''H. vini'' }} }} }} }} }} }} |}
==References== {{Reflist}}
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Category:Bacillaceae Category:Bacteria genera