Abstract
Na.no.ha.lo'bi.um. Gr. masc. n.
nanos
a dwarf; Gr. masc. n.
hals
,
halos
salt; Gr. masc. n.
bios
life; N.L. neut. n.
Nanohalobium
small organism living in salt.
The genus
Candidatus
Nanohalobium was established based on a genome sequence found after the enrichment, cultivation, and characterization of a binary association with its chitinolytic host, obtained from a crystallizer pond brine collected in the marine solar saltern Saline della Laguna of Trapani, Italy.
Ca
. Nanohalobium is phylogenetically affiliated with members of the
Ca
. Nanohaloarchaeota (
Candidatus
Haloredivivus,
Candidatus
Nanosalina, and
Candidatus
Nanosalinicola) of the archaeal DPANN superphylum. Cultivation experiments and analysis of the 0.97 Mb genome of
Ca
. Nanohalobium constans LC1Nh revealed that the organism has an organoheterotrophic, sugar‐fermenting lifestyle, lacking key anabolic machinery and any respiratory complexes. Additionally, the cultivation experiments revealed a remarkable mutualism of a nanohaloarchaeon–haloarchaeon association, namely the nanohaloarchaeon's ability to hydrolyze glycogen and starch to glucose, enabling the growth of
Halomicrobium
sp. LC1Hm in the absence of chitin. The low‐median isoelectric point for the predicted proteins suggests a “salt‐in” strategy used by the nanohaloarchaeon for osmotic balance. 16S rRNA gene sequences affiliated with
Ca
. Nanohalobium were recovered from other saltern ponds and hypersaline lakes worldwide.
DNA G + C content (mol%)
: 43.2 (genome).
Type species
:
Candidatus
Nanohalobium constans
, La Cono et al. 2020.
Taxonomic and Nomenclature Notes
According to the List of Prokaryotic names with Standing in Nomenclature (LPSN), the taxonomic status of the genus
Candidatus Nanohalobium
is: preferred name (not correct name) (last update, February 2025)
*
.
LPSN classification:
Archaea
/
Nanobdellati
/
Candidatus Nanohalarchaeota
/
Candidatus Nanohalobiia
/
Candidatus Nanohalobiales
/
Candidatus Nanohalobiaceae
/
Candidatus Nanohalobium
The genus
Candidatus Nanohalobium
can also be recovered in the Genome Taxonomy Database (GTDB) as
g__Nanohalobium
(version v220)
**
.
GTDB classification:
d__Archaea
/
p__Nanohaloarchaeota
/
c__Nanosalinia
/
o__Nanosalinales
/
f__Nanosalinaceae
/
g__Nanohalobium
*
Meier‐Kolthoff
et al. (
2022
).
Nucleic Acids Res
,
50
,
D801
–
D807
; DOI:
10.1093/nar/gkab902
**
Parks
et al. (
2022
).
Nucleic Acids Res
,
50
,
D785
–
D794
; DOI:
10.1093/nar/gkab776