Haloferacales is an order of halophilic, chemoorganotrophic or heterotrophic archaea within the class Haloarchaea.[3] The type genus of this order is Haloferax.[4]

Haloferacales
Scientific classification Edit this classification
Domain: Archaea
Kingdom: Euryarchaeota
Class: Halobacteria
Order: Haloferacales
Gupta et al. 2015
Families[1][2]

The name Haloferacales is derived from the Latin term Haloferax, referring to the type genus of the order and the suffix "-ales," an ending used to denote an order. Together, Haloferacales refers to an order whose nomenclatural type is the genus Haloferax.

Biochemical characteristics and molecular signatures

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Members are halophiles and can be chemoorganotrophs or heterotrophs and are isolated from high-salt environments such as marine solar salterns and the Dead Sea. Some members are motile and contain gas vesicles. Morphology is variable, including rod, coccus or flat square shapes. Members of this order grow optimally in neutral pH. The DNA G+C content for this order ranges between 55-66 mol%.[3]

This order can be reliably distinguished from other Halobacteria by the presence of five conserved signature proteins (CSPs) and four conserved signature indels (CSIs) present in the following proteins: DNA gyrase B, prolyl t-RNA synthetase, acyl-CoA synthetase and aspartyl/glutamyl-tRNA amido-transferase subunit B.[3]

Historical systematics and current taxonomy

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As of 2021, Haloferacales contains two families, Haloferacaceae and Halorubraceae.[4] Members of this order was demarcated from the class Halobacteria, previously a large phylogenetically unrelated group of species with distinct biochemical characteristics and different ecological niches.[5][6] The diverse range of morphological and physiological characteristics made it difficult to clarify the evolutionary relationship within the class beyond a genus level.

In 2015, Gupta et al. proposed the division of the class Halobacteria into the orders Halobacteriales, Haloferacales and Natrialbales based on comparative genomic analyses and the branching pattern of various phylogenetic trees constructed from several different datasets of conserved proteins and 16S rRNA sequences. Molecular markers, specifically conserved signature indels, specific to this order were also identified as evidence supporting the division independent of phylogenetic trees.[3] Each order can be reliably distinguished from each other and other species based on the presence of these CSIs.

Phylogeny

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The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN)[2] and National Center for Biotechnology Information (NCBI).[1]

16S rRNA based LTP_06_2022[7][8][9] 53 marker proteins based GTDB 08-RS214[10][11][12]
Haloferacales
Haloferacales

Halobaculum Oren et al. 1995

Halolamina Cui et al. 2011

Natronocalculus Sorokin et al. 2023

"Halalkalirubrum" Zuo et al. 2021

Halohasta Mou et al. 2013

Halonotius Burns et al. 2010

Halalkaliarchaeum Sorokin et al. 2019

Halopenitus Amoozegar et al. 2012

Haloparvum Chen et al. 2016

Halorubrum McGenity & Grant 1996

Haloplanus Elevi Bardavid et al. 2007

Salinirubrum corrig. Cui and Qiu 2014

Haloprofundus Zhang et al. 2017

Halegenticoccus Liu et al. 2020

Halogranum Cui et al. 2010

Salinigranum Cui and Zhang 2014

Haloferax Torreblanca et al. 1986

Halopelagius Cui et al. 2010

Halogeometricum Montalvo-Rodriguez et al. 1998

Haloquadratum Burns et al. 2007

Halobellus Cui et al. 2011

Haloferacaceae

See also

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References

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  1. ^ a b Sayers; et al. "Haloferacales". National Center for Biotechnology Information (NCBI) taxonomy database. Retrieved 2023-05-17.
  2. ^ a b J.P. Euzéby. "Haloferacales". List of Prokaryotic names with Standing in Nomenclature (LPSN). Retrieved 2023-05-17.
  3. ^ a b c d Gupta, Radhey S.; Naushad, Sohail; Baker, Sheridan (2015-03-01). "Phylogenomic analyses and molecular signatures for the class Halobacteria and its two major clades: a proposal for division of the class Halobacteria into an emended order Halobacteriales and two new orders, Haloferacales ord. nov. and Natrialbales ord. nov., containing the novel families Haloferacaceae fam. nov. and Natrialbaceae fam. nov". International Journal of Systematic and Evolutionary Microbiology. 65 (Pt_3): 1050–1069. doi:10.1099/ijs.0.070136-0. ISSN 1466-5026.
  4. ^ a b "Order: Haloferacales". lpsn.dsmz.de. Retrieved 2021-06-27.
  5. ^ Grant, William D.; Kamekura, Masahiro; McGenity, Terry J.; Ventosa, Antonio (2015-09-14). "Halobacteria class. nov". Bergey's Manual of Systematics of Archaea and Bacteria: 1–1. doi:10.1002/9781118960608.cbm00026.
  6. ^ Oren, Aharon (2012-02-01). "Taxonomy of the family Halobacteriaceae: a paradigm for changing concepts in prokaryote systematics". International Journal of Systematic and Evolutionary Microbiology. 62 (2): 263–271. doi:10.1099/ijs.0.038653-0. ISSN 1466-5026.
  7. ^ "The LTP". Retrieved 10 May 2023.
  8. ^ "LTP_all tree in newick format". Retrieved 10 May 2023.
  9. ^ "LTP_06_2022 Release Notes" (PDF). Retrieved 10 May 2023.
  10. ^ "GTDB release 08-RS214". Genome Taxonomy Database. Retrieved 10 May 2023.
  11. ^ "ar53_r214.sp_label". Genome Taxonomy Database. Retrieved 10 May 2023.
  12. ^ "Taxon History". Genome Taxonomy Database. Retrieved 10 May 2023.