Deinococcota (synonym,"Deinococcus-Thermus") is aphylum ofbacteria with a single class,Deinococci (fromAncient Greek δεινός (deinós), meaning "terrible", and κόκκος (kókkos), meaning "berry"[4]), that are highly resistant to environmental hazards, also known asextremophiles.[5]
These bacteria have thick cell walls that give themgram-positive stains, but they include a second membrane and so are closer in structure to those ofgram-negative bacteria.[6][7][8]
Molecular signatures in the form ofconserved signature indels (CSIs) and proteins (CSPs) have been found that are uniquely shared by all members belonging to the Deinococcota phylum.[5][12] TheseCSIs and CSPs are distinguishing characteristics that delineate the unique phylum from all other bacterial organisms, and their exclusive distribution is parallel with the observed differences in physiology. CSIs and CSPs have also been found that support order and family-level taxonomic rankings within the phylum. Some of the CSIs found to support order level distinctions are thought to play a role in the respectiveextremophilic characteristics.[12] The CSIs found inDNA-directed RNA polymerase subunit beta andDNA topoisomerase I inThermales species may be involved inthermophilicity,[17] while those found inExcinuclease ABC,DNA gyrase, andDNA repair proteinRadA inDeinococcales species may be associated withradioresistance.[18]
Additionally, some genera within this group, includingDeinococcus,Thermus, andMeiothermus, also have molecular signatures that demarcate them as individual genera, inclusive of their respective species, providing a means to distinguish them from the rest of the group and all other bacteria.[12] Two CSPs that were found uniquely for all members belonging to theDeinococcus genus are well characterized and are thought to play a role in their characteristic radioresistant phenotype. These CSPs include the DNA damage repair proteinPprA and the single-stranded DNA-binding proteinDdrB.[12]
Class DeinococciGarrity & Holt 2002 ["Deinococcia"Oren, Parte & Garrity 2016 ex Cavalier-Smith 2020; "Thermi"Rinke et al. 2013; "Thermia"Cavalier-Smith 2020]
OrderDeinococcalesRainey et al. 1997 [TrueperalesGarcía-López et al. 2020]
FamilyDeinococcaceaeBrooks and Murray 1981 emend. Rainey et al. 1997
GenusDeinococcusBrooks and Murray 1981 emend. Rainey et al. 1997
Currently there are 10 sequenced genomes of strains in this phylum.[27]
Deinococcus radiodurans R1
Thermus thermophilus HB27
Thermus thermophilus HB8
Deinococcus geothermalis DSM 11300
Deinococcus deserti VCD115
Meiothermus ruber DSM 1279
Meiothermus silvanus DSM 9946
Truepera radiovictrix DSM 17093
Oceanithermus profundus DSM 14977
The twoMeiothermus species were sequenced under the auspices of theGenomic Encyclopedia of Bacteria and Archaea project (GEBA), which aims at sequencing organisms based on phylogenetic novelty and not on pathogenicity or notoriety.[28]
^Garrity GM, Holt JG (2001). "The Road Map to the Manual". In Boone DR, Castenholz RW, Garrity GM (eds.).Bergey's Manual of Systematic Bacteriology. Vol. 1 (The Archaea and the deeply branching and phototrophic Bacteria) (2nd ed.). New York, NY: Springer–Verlag. pp. 119–166.
^Sutcliffe IC (2010). "A phylum level perspective on bacterial cell envelope architecture".Trends Microbiol.18 (10):464–470.doi:10.1016/j.tim.2010.06.005.PMID20637628.
^abGarrity GM, Holt JG. (2001) Phylum BIV. "Deinococcus–Thermus". In: Bergey’s manual of systematic bacteriology, pp. 395-420. Eds D. R. Boone, R. W. Castenholz. Springer-: New York.
^abGarrity GM, Bell JA, Lilburn TG. (2005) Phylum BIV. The revised road map to the Manual. In: Bergey’s manual of systematic bacteriology, pp. 159-220. Eds Brenner DJ, Krieg NR, Staley JT, Garrity GM. Springer-: New York.
^abcdefghHo J, Adeolu M, Khadka B, Gupta RS (2016). "Identification of distinctive molecular traits that are characteristic of the phylum "Deinococcus–Thermus" and distinguish its main constituent groups".Syst Appl Microbiol.39 (7):453–463.doi:10.1016/j.syapm.2016.07.003.PMID27506333.
^Battista JR, Earl AM, Park MJ (1999). "Why isDeinococcus radiodurans so resistant to ionizing radiation?".Trends Microbiol.7 (9):362–5.doi:10.1016/S0966-842X(99)01566-8.PMID10470044.
^Nelson RM, Long GL (1989). "A general method of site-specific mutagenesis using a modification of the Thermus aquaticus".Anal Biochem.180 (1):147–151.doi:10.1016/0003-2697(89)90103-6.PMID2530914.
