Hyphomicrobiales

The Hyphomicrobiales (synonom Rhizobiales) are an order of Gram-negative Alphaproteobacteria.

Hyphomicrobiales
Agrobacterium (SEM image)
Scientific classification Edit this classification
Domain:Bacteria
Phylum:Pseudomonadota
Class:Alphaproteobacteria
Order:Hyphomicrobiales
Douglas 1957 (Approved Lists 1980)
Families[1]

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Synonyms[2]
  • Rhizobiales Kuykendall 2006

The rhizobia, which fix nitrogen and are symbiotic with plant roots, appear in several different families. The four families Nitrobacteraceae, Hyphomicrobiaceae, Phyllobacteriaceae, and Rhizobiaceae contain at least several genera of nitrogen-fixing, legume-nodulating, microsymbiotic bacteria. Examples are the genera Bradyrhizobium and Rhizobium. Species of the Methylocystaceae are methanotrophs; they use methanol (CH3OH) or methane (CH4) as their sole energy and carbon sources. Other important genera are the human pathogens Bartonella and Brucella, as well as Agrobacterium (useful in genetic engineering).

Taxonomy

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Accepted families

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Unassigned Genera

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The following genus has not been assigned to a family:

Provisional Taxa

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These taxa have been published, but have not been validated according to the Bacteriological Code:

  • "Nordella" La Scola et al. 2004[4]
  • "Propylenellaceae" Liu et al. 2021[5]
    • "Propylenella" Liu et al. 2021[5]
      • "Propylenella binzhouense" Liu et al. 2021[5]
  • "Thermopetrobacter" Sislak 2013[6]

Phylogeny

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The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature[7] and the phylogeny is based on whole-genome sequences.[2][a]

Natural genetic transformation

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Natural genetic transformation has been reported in at least four Hyphomicrobiales species: Agrobacterium tumefaciens,[8] Methylobacterium organophilum,[9] Ensifer adhaerens,[10] and Bradyrhizobium japonicum.[11] Natural genetic transformation is a sexual process involving DNA transfer from one bacterial cell to another through the intervening medium, and the integration of the donor sequence into the recipient genome by homologous recombination.

See also

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Notes

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  1. ^ Aestuariivirgaceae, Alsobacteraceae, Ancalomicrobiaceae, Lichenibacteriaceae, Lichenihabitantaceae, Rhabdaerophilaceae, and Segnochrobactraceae are not included in this phylogenetic tree.
  2. ^ Phyllobacterium is separate from the rest of Phyllobacteriaceae.
  3. ^ Prosthecomicrobium is separate from the rest of Hyphomicrobiaceae.

References

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Further reading

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  • Kuykendall LD, Dazzo FB (2005). "Allorhizobium". In Brenner DJ, Krieg NR, Staley JT, Garrity G (eds.). The Alpha-, Beta-, Delta- and Epsilonproteobacteria, The Proteobacteria, Part C, Bergey's Manual of Systematic Bacteriology. Vol. 2 (2nd ed.). Springer, New York, NY. pp. 345–346. ISBN 978-0-387-24144-9.
  • Kuykendall LD (2005). "Genus Azorhizobium". In Brenner DJ, Krieg NR, Staley JT, Garrity G (eds.). The Alpha-, Beta-, Delta- and Epsilonproteobacteria, The Proteobacteria, Part C, Bergey's Manual of Systematic Bacteriology. Vol. 2 (2nd ed.). Springer, New York, NY. pp. 505–506. ISBN 978-0-387-24144-9.
  • Kuykendall LD (2005). "Genus Bradyrhizobium, family Bradyrhizobiaceae'". In Brenner DJ, Krieg NR, Staley JT, Garrity G (eds.). The Alpha-, Beta-, Delta- and Epsilonproteobacteria, The Proteobacteria, Part C, Bergey's Manual of Systematic Bacteriology. Vol. 2 (2nd ed.). Springer, New York, NY. pp. 438–443. ISBN 978-0-387-24144-9.
  • Kuykendall LD, Young JM, Martínez-Romero, Kerr A, Sawada H (2005). "Genus Rhizobium, a highly divergent genus in a revised family". In Brenner DJ, Krieg NR, Staley JT, Garrity G (eds.). The Alpha-, Beta-, Delta- and Epsilonproteobacteria, The Proteobacteria, Part C, Bergey's Manual of Systematic Bacteriology. Vol. 2 (2nd ed.). Springer, New York, NY. pp. 324–340. ISBN 978-0-387-24144-9.
  • Chen WX, Wang ET, Kuykendall LD (2005). "enus Mesorhizobium, Family Photobacteriaceae.". In Brenner DJ, Krieg NR, Staley JT, Garrity G (eds.). The Alpha-, Beta-, Delta- and Epsilonproteobacteria, The Proteobacteria, Part C, Bergey's Manual of Systematic Bacteriology. Vol. 2 (2nd ed.). Springer, New York, NY. pp. 403–408. ISBN 978-0-387-24144-9.