CGB - Universidad Mayor

08 febrero 2019

Uncovering the Mechanisms of Halotolerance in the Extremely Acidophilic Members of the Acidihalobacter Genus Through Comparative Genome Analysis.

DOI : 10.3389/fmicb.2019.00155


There are few naturally occurring environments where both acid and salinity

stress exist together, consequently, there has been little evolutionary pressure

for microorganisms to develop systems that enable them to deal with both

stresses simultaneously. Members of the genus Acidihalobacter are iron- and

sulfur-oxidizing, halotolerant acidophiles that have developed the ability to

tolerate acid and saline stress and, therefore, have the potential to bioleach

ores with brackish or saline process waters under acidic conditions. The genus

consists of four members, A. prosperus DSM 5130T, A. prosperus DSM 14174, A.

prosperus F5 and "A. ferrooxidans" DSM 14175. An in depth genome comparison was

undertaken in order to provide a more comprehensive description of the

mechanisms of halotolerance used by the different members of this genus.

Pangenome analysis identified 29, 3 and 9 protein families related to

halotolerance in the core, dispensable and unique genomes, respectively. The

genes for halotolerance showed Ka/Ks ratios between 0 and 0.2, confirming that

they are conserved and stabilized. All the Acidihalobacter genomes contained

similar genes for the synthesis and transport of ectoine, which was recently

found to be the dominant osmoprotectant in A. prosperus DSM 14174 and A.

prosperus DSM 5130T. Similarities also existed in genes encoding low affinity

potassium pumps, however, A. prosperus DSM 14174 was also found to contain genes

encoding high affinity potassium pumps. Furthermore, only A. prosperus DSM 5130T

and "A. ferrooxidans" DSM 14175 contained genes allowing the uptake of taurine

as an osmoprotectant. Variations were also seen in genes encoding proteins

involved in the synthesis and/or transport of periplasmic glucans, sucrose,

proline, and glycine betaine. This suggests that versatility exists in the

Acidihalobacter genus in terms of the mechanisms they can use for halotolerance.

This information is useful for developing hypotheses for the search for life on

exoplanets and moons.

Investigadores Participantes del Centro



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