{{Short description|Order of Actinomycota}} {{Automatic taxobox | image = Actinomyces_israelii.jpg | image_caption = [[Scanning electron micrograph]] of ''Actinomyces israelii''. | taxon = Actinomycetales | authority = Buchanan 1917 (Approved Lists 1980)<ref>{{cite journal |vauthors= Buchanan RE | title = Studies in the Nomenclature and Classification of the Bacteria: II. The Primary Subdivisions of the ''Schizomycetes'' | journal = J Bacteriol | year = 1917 | volume = 2 | pages = 155–164 | pmid = 16558735 | pmc = 378699 | doi = 10.1128/jb.2.2.155-164.1917}}</ref><ref name=LPSN/> | type_genus = ''[[Actinomyces]]'' | type_genus_authority = Harz 1877 (Approved Lists 1980) | subdivision_ranks = Families | subdivision_ref = <ref name=NCBI/> | subdivision = [[#Phylogeny|See text]] | synonyms = * "Actinobacteriales" <small>Prévot 1946</small> * Actinomycetineae <small>Stackebrandt, Rainey & Ward-Rainey 1997</small> }}
'''Actinomycetales''' is an [[Scientific classification|order]] of [[Actinomycetota]]. A member of the order is often called an '''actinomycete'''. Actinomycetales are generally [[Gram-positive bacteria|gram-positive]] and anaerobic and have mycelia in a filamentous and branching growth pattern. Some actinomycetes can form rod- or coccoid-shaped forms, while others can form spores on aerial [[hypha]]e. Actinomycetales bacteria can be infected by [[bacteriophage]]s, which are called actinophages. Actinomycetales can range from harmless bacteria to pathogens with resistance to antibiotics.
==Reproduction== Actinomycetales have 2 main forms of reproduction: [[spore]] formation and hyphae fragmentation. During reproduction, Actinomycetales can form [[conidiophores]], sporangiospores, and oidiospores. In reproducing through hyphae fragmentation, the hyphae formed by Actinomycetales can be a fifth to half the size of fungal hyphae, and bear long spore chains.
==Presence and associations== {{unreferenced section|date=May 2026}} Actinomycetales can be found mostly in soil and decaying organic matter, as well as in living organisms such as humans and animals. They form symbiotic [[nitrogen fixing]] associations with over 200 species of plants, and can also serve as growth promoting or biocontrol agents, or cause disease in some species of plants. Actinomycetales can be found in the human [[urogenital]] tract as well as in the [[digestive system]] including the mouth, throat, and [[gastrointestinal]] tract in the form of Helicobacter without causing disease in the host. They also have wide medicinal and [[botanical]] applications, and are used as a source of many [[antibiotics]] and [[pesticides]].
==Antimicrobial properties== Many species of Actinomycetes produce antimicrobial compounds under certain conditions and growth media. [[Streptomycin]], [[actinomycin]], and [[streptothricin]] are all medically important antibiotics isolated from Actinomycetes bacteria.<ref>{{cite journal|last1=Waksman|first1=Selman A.|last2=Schatz|first2=Albert|last3=Reynolds|first3=Donald M.|title=Production of antibiotic substances by Actinomycetes|journal=Annals of the New York Academy of Sciences|date=December 2010|volume=1213|issue=1|pages=112–124|doi=10.1111/j.1749-6632.2010.05861.x|pmid=21175680|doi-access=free}}</ref> Almost two-thirds of the natural antimicrobial drug compounds used currently are produced by different species of Actinomycetes.<ref>{{cite journal|last1=Bentley|first1=S. D.|last2=Chater|first2=K. F.|last3=Cerdeño-Tárraga|first3=A.-M.|last4=Challis|first4=G. L.|last5=Thomson|first5=N. R.|last6=James|first6=K. D.|last7=Harris|first7=D. E.|last8=Quail|first8=M. A.|last9=Kieser|first9=H.|last10=Harper|first10=D.|last11=Bateman|first11=A.|last12=Brown|first12=S.|last13=Chandra|first13=G.|last14=Chen|first14=C. W.|last15=Collins|first15=M.|last16=Cronin|first16=A.|last17=Fraser|first17=A.|last18=Goble|first18=A.|last19=Hidalgo|first19=J.|last20=Hornsby|first20=T.|last21=Howarth|first21=S.|last22=Huang|first22=C.-H.|last23=Kieser|first23=T.|last24=Larke|first24=L.|last25=Murphy|first25=L.|last26=Oliver|first26=K.|last27=O'Neil|first27=S.|last28=Rabbinowitsch|first28=E.|last29=Rajandream|first29=M.-A.|last30=Rutherford|first30=K.|last31=Rutter|first31=S.|last32=Seeger|first32=K.|last33=Saunders|first33=D.|last34=Sharp|first34=S.|last35=Squares|first35=R.|last36=Squares|first36=S.|last37=Taylor|first37=K.|last38=Warren|first38=T.|last39=Wietzorrek|first39=A.|last40=Woodward|first40=J.|last41=Barrell|first41=B. G.|last42=Parkhill|first42=J.|last43=Hopwood|first43=D. A.|title=Complete genome sequence of the model actinomycete ''Streptomyces coelicolor'' A3(2)|journal=Nature|date=9 May 2002|volume=417|issue=6885|pages=141–147|doi=10.1038/417141a|pmid=12000953|doi-access=free}}</ref>
==Phylogeny== The currently accepted taxonomy is based on the [[List of Prokaryotic names with Standing in Nomenclature]] (LPSN)<ref name=LPSN>{{cite web |author=A.C. Parte |url=https://lpsn.dsmz.de/order/actinomycetales |title=Actinomycetales |access-date=2025-02-28 |publisher=[[List of Prokaryotic names with Standing in Nomenclature]] (LPSN) |display-authors=et al.}}</ref> and [[National Center for Biotechnology Information]] (NCBI).<ref name=NCBI>{{cite web |author=C.L. Schoch |url=https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Tree&id=2037&lvl=3&lin=f&keep=1&srchmode=1&unlock |title=Actinomycetales |access-date=2025-02-28 |publisher=[[National Center for Biotechnology Information]] (NCBI) taxonomy database |display-authors=et al.}}</ref>
{| class="wikitable" |- ! colspan=1 | Whole-genome based phylogeny<ref name="Nouioui">{{cite journal |vauthors=Nouioui I, Carro L, García-López M, Meier-Kolthoff JP, Woyke T, Kyrpides NC, Pukall R, Klenk HP, Goodfellow M, Markus Göker M | year = 2018 | title = Genome-Based Taxonomic Classification of the Phylum ''Actinobacteria'' | journal = Front. Microbiol. | volume = 9 | pages = 2007 | pmid = 30186281 | pmc = 6113628 | doi = 10.3389/fmicb.2018.02007| doi-access = free }}</ref> ! colspan=1 | 16S rRNA based [[The All-Species Living Tree Project|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 [[Genome Taxonomy Database|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 |label1=[[Microbacteriales]] |1={{clade |1="[[Tropherymataceae]]" |2=[[Microbacteriaceae]] }} }} |2={{clade |1={{clade |label1=[[Kineosporiales]] |1={{clade |1="Quadrisphaeraceae" [incl. "Kineococcaceae"] |2={{clade |1=[[Kineosporiaceae]] |2={{clade |1={{clade |1=[[Kytococcaceae]] |2=[[Ornithinimicrobiaceae]] }} |2={{clade |1=[[Dermatophilaceae]] |2={{clade |1=[[Dermacoccaceae]] |2=[[Intrasporangiaceae]] }} }} }} }} }} }} |2={{clade |1={{clade |1={{clade |label1=[[Bifidobacteriales]] |1=[[Bifidobacteriaceae]] |label2=Actinomycetales |2=[[Actinomycetaceae]] }} |2={{clade |label1=[[Cellulomonadales]] |1={{clade |1=[[Demequinaceae]] |2={{clade |1={{clade |1=[[Beutenbergiaceae]] |2={{clade |1=[[Bogoriellaceae]] |2=[[Ruaniaceae]] }} }} |2={{clade |1=[[Cellulomonadaceae]] |2={{clade |1=[[Jonesiaceae]] |2=[[Promicromonosporaceae]] }} }} }} }} }} }} |2={{clade |label1=[[Micrococcales]] |1={{clade |1=[[Dermabacteraceae]] |2={{clade |1=[[Brevibacteriaceae]] |2=[[Micrococcaceae]] }} }} }} }} }} }} }} | {{Clade | style=font-size:90%;line-height:80% |1={{clade |1={{clade |label1=[[Bifidobacteriales]] |1=[[Bifidobacteriaceae]] }} |2={{clade |1=other |2={{clade |1=other |2={{clade |1=other |2={{clade |1={{clade |label1=[[Kineosporiales]] |1=[[Kineosporiaceae]] [incl. Angustibacteraceae; [[Aquipuribacteraceae]]; "Kineococcaceae"; Quadrisphaeraceae] }} |2={{clade |1={{clade |label1=[[Microbacteriales]] |1={{clade |1={{clade |1="''[[Caespitibacter]]''" |2=[[Tropherymataceae]] }} |2=[[Microbacteriaceae]] }} }} |2={{clade |1={{clade |label1=[[Cellulomonadales]] |1={{clade |1={{clade |1=''[[Pseudactinotalea]]'' |2=[[Demequinaceae]] }} |2={{clade |1=[[Sanguibacteraceae]] |2={{clade |1=[[Oerskoviaceae]] |2={{clade |1=[[Actinotaleaceae]] |2=[[Cellulomonadaceae]] }} }} }} }} }} |2={{clade |1={{clade |label1=Actinomycetales |1={{clade |1={{clade |1=[[Bogoriellaceae]] |2={{clade |1=[[Beutenbergiaceae]] |2=[[Ruaniaceae]] }} }} |2={{clade |1={{clade |1=[[Rarobacteraceae]] |2=[[Promicromonosporaceae]] }} |2={{clade |1=[[Jonesiaceae]] |2=[[Actinomycetaceae]] [incl. [[Arcanobacteriaceae]]] }} }} }} }} |2={{clade |label1=[[Dermatophilales]] |1={{clade |1=[[Dermabacteraceae]] |2={{clade |1={{clade |1=[[Dermacoccaceae]] |2={{clade |1=[[Dermatophilaceae]] [incl. [[Arsenicicoccaceae]]] |2=[[Ornithinimicrobiaceae]] }} }} |2=[[Intrasporangiaceae]] [incl. [[Kytococcaceae]]] }} }} |label2=[[Micrococcales]] |2={{clade |1=[[Brevibacteriaceae]] |2=[[Micrococcaceae]] [incl. [[Yaniellaceae]]] }} }} }} }} }} }} }} }} }} }} }} | {{Clade | style=font-size:90%;line-height:90% |label1=Actinomycetales |1={{clade |1={{clade |label1="Polyseptineae" |1={{clade |1={{clade |1=[[Angustibacteraceae]] |2=[[Dermatophilaceae]] [incl. [[Arsenicicoccaceae]]; [[Dermacoccaceae]]; [[Kytococcaceae]]; [[Ornithinimicrobiaceae]]; [[Intrasporangiaceae]]] }} }} }} |2={{clade |1={{clade |label1=Kineosporiineae |1={{clade |1=[[Quadrisphaeraceae]] [incl. [[Aquipuribacteraceae]]] |2={{clade |1=[[Kineosporiaceae]] |2="Kineococcaceae" }} }} }} |2={{clade |label1=Actinomycetineae |1={{clade |1=[[Dermabacteraceae]] |2={{clade |1=[[Demequinaceae]] |2={{clade |1=[[Cellulomonadaceae]] [incl. [[Actinotaleaceae]]; [[Jonesiaceae]]; [[Oerskoviaceae]]; [[Promicromonosporaceae]]; [[Rarobacteraceae]]; [[Sanguibacteraceae]]] |2={{clade |1=[[Beutenbergiaceae]] [incl. [[Ruaniaceae]]] |2=[[Actinomycetaceae]] [incl. [[Arcanobacteriaceae]]; [[Bogoriellaceae]]] }} }} }} }} |label2=Micrococcineae |2={{clade |1=[[Brevibacteriaceae]] |2={{clade |1=[[Micrococcaceae]] [incl. [[Yaniellaceae]]] |2={{clade |1=[[Bifidobacteriaceae]] |2=[[Microbacteriaceae]] [incl. [[Tropherymataceae]]] }} }} }} }} }} }} }} |}
==See also== * [[Bacterial taxonomy]] * [[List of bacterial orders]] * [[List of bacteria genera]]
==References== {{Reflist|30em}}
{{Portal bar|Biology}} {{Bacteria classification}} {{Taxonbar|from=Q343452}} {{Authority control}} [[Category:Actinomycetales| ]] [[Category:Bacteria orders]]