Polyphasic Identification of a Novel Halophilic Archaeon Isolated From a Solar Saltern in Spain

BACKGROUND AND ABJECTIVEExtremely halophilic archaea belonging to domain Archaea, represent a unique group of microorganisms that have been isolated from solar salterns with very high salinity. During a survey on SA` Vall solar saltern (Mallorca, Spain), a haloarchaeal strain designated AV۲۲۰B۸۷T was isolated from a brine sample and found to be closely related to members of genus Halohasta.MATERIALS AND METHODSPhenotypic characterization of the strain AV۲۲۰B۸۷T was performed according to proposed minimal standard protocols. Polar lipids were analyzed using thin-layer chromatography. ۱۶S rRNA gene sequence analysis was performed by cloning PCR products and EzBioCloud server was used for sequence similarity analysis. The phylogenetic position was determined in trees reconstructed using neighbor-joining, maximum likelihood and minimum evolution algorithms.RESULTS AND DISCUSSIONResults show that cells of this strain are non-motile and gram-stain-negative. Optimal NaCl, Mg۲+, pH and temperature for growth are ۳.۵ M, ۰.۱ M, ۷ and ۴۰ ºC, respectively. Reduction of nitrate to nitrite and indole production is negative. Cells hydrolyze gelatin while casein, starch and tween ۸۰ hydrolysis is negative. No growth observed with DMSO and L-arginine. Furthermore, the strain AV۲۲۰B۸۷T is sensitive to: novobiocin, rifamycin B, Nitrofurantoin. The total polar lipid pattern include phosphatidylglycerol, phosphatidic acid, phosphatidylglycerol sulfate, phosphatidylglycerol phosphate methyl ester with some unknown phospholipids and glycolipids. The ۱۶S rRNA gene sequence of strain AV۲۲۰B۸۷T share the highest sequence similarity with members of Halohasta (Halohasta litorea R۳۰T and Halohasta litchfieldiae tADLT, ۹۷.۸% and ۹۷.۱% respectively). Moreover, based on the neighbour-joing tree, strain AV۲۲۰B۸۷T constitute a distinct monophyletic branch.CONCLUSIONThe sequence similarity of strain AV۲۲۰B۸۷T to the most closely related genera and phylogenetic trees indicate that this strain can be represented as a novel species in the genus Halohasta within the family Haloferacaceae.

کلیدواژه ها:

Solar Salterns ، Halophilic Archaea ، Polyphasic Identification