Halorubrum

A population of the haloarchaea Halorubrum in its natural high salt concentration environment exchanged genetic information frequently by recombination.^[2] This population exhibited a degree of linkage equilibrium approaching that of a sexual population.

Halorubrum ejinorense was first isolated from Lake Ejinor in Inner Mongolia, China.^[3]

Halorubrum lacusprofundi was first isolated in the 1980s from Deep Lake, Antarctica.^[4] Its genome, sequenced in 2008, consists of two chromosomes (one 2.74 Mb and the other 0.53 Mb) and one plasmid (0.43 Mb).^[5] Its β-galactosidase enzyme has been extensively studied to understand how proteins function in low-temperature, high-saline environments.^[6][7] One strain of H. lacusprofundi contains a plasmid for horizontal gene transfer, which takes place via a mechanism that uses vesicle-enclosed virus-like particles.^[8]

Halorubrum sodomense was first identified in the Dead Sea in 1980. It requires a higher concentration of Mg²⁺ ions for growth than related halophiles.^[9] Its cell surface membrane contains Archaerhodopsin-3 (AR3), a photoreceptor protein which harvests the energy from sunlight to establish a proton motive force that is used for ATP synthesis.^[10][11] Mutants of AR3 are widely used as tools in optogenetics for neuroscience research.^[12]

Halorubrum tibetense was first isolated from Lake Zabuye in Tibet, China.^[13]

Halorubrum xinjiangense was first isolated from Xiao-Er-Kule Lake in Xinjiang, China.^[14]

Proposed species

Several species and novel binomial names have been proposed, but not validly published. published.

• "Halorubrum africanae" Kharroub et al. 2007b and "Halorubrum constantinense" Kharroub et al. 2007b were isolated in Algeria and proposed as new species in 2007^[15] and 2005.^[16]
• "Halorubrum alimentarium" Nam et al. 2008 nom. nud. and "Halorubrum koreense" Nam et al. 2008 nom. nud. are the proposed names for the undescribed strains B43 and B6, appearing in a publication of 2008.^[17]
• "Halorubrum halotolerans" Sabet et al. 2009 is the proposed name for an undescribed strain isolated from solar salterns in Baja California in 2009.^[18]
• Halorubrum hochstenium is the proposed name for the full genome of the undescribed strain ATCC 700873, supplied to databases in 2014.^[19][20]
• "Halorubrum jeotgali" Roh et al. 2007b was isolated from samples of traditional Korean seafood and proposed as new species in 2007.^[21] Halorubrum cibarium was proposed in the same publication. It was proposed again under the name H. cibi and accepted in 2009.
• "Halorubrum kribbense" Nkamga, Henrissat & Drancourt 2017 and "Halorubrum norisence" Nkamga, Henrissat & Drancourt 2017 are proposed names of unisolated strains from the human gut microbiome, referenced in a publication in 2017.^[22]
• H. miltondacostae Albuquerque et al. 2025
• "Halorubrum salipaludis" Gong et al. 2021 was first published in 2021.^[23]
• "Halorubrum salsolis"
• Halorubrum salsamenti was isolated from salt brine and proposed as new species in 2017.^[24]
• "Halorubrum sfaxense" Trigui et al. 2011 was isolated in Tunisia and proposed as new species in 2017.^[25]
• "Halorubrum tropicale" was isolated in Puerto Rico and proposed as new species in 2016.^[26]