Bioinformatics delimitation of the psychrophilic and psychrotolerant actinobacteria isolated from the Polar Frontal waters of the Southern Ocean

Identification of microorganisms plays a key role in the determination of the composition of microbial diversity for bioprospecting of biotechnologically important biomolecules. Digitalization is the process that solve discrepancies in microbial identification and cataloguing their diversity in distinct ecological habitats. In view of this connection, the psychrophilic and psychrotolerant actinobacteria were isolated from the water samples of the Polar Frontal region of the Southern Ocean. 16S rRNA gene sequencing for identification of psychrophiles was carried out and sequences were deposited in NCBI GeneBank. 16S rRNA gene sequences were used to create QR codes, CGR, FCGR and GC plot. This generated digital data help to relate the diversity amongst the isolated actinobacterial strains. The digital data showed considerable divergence among the actinobacterial strains. This generated bioinformatics data is helpful in the delimitation of the psychrophilic and psychrotolerant actinobacteria. Thus, the present study is a robust and accurate method for the identification of Polar microorganisms in a fixed boundary. Hence, this work will help to assign a unique digital identity to microorganisms in near future [9-19].

& 2018 The Authors.Published by Elsevier Inc.This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Subject area
Marine

Value of the data
Bioinformatics data of the psychrophilic and psychrotolerant actinobacteria of the Polar Frontal waters have significant importance in the biodiversity and biotechnology of microorganisms found in the polar regions and other cold environments.
An earnest attempt was made to digitize the 16S rRNA gene sequence of the psychrophilic and psychrotolerant actinobacteria of the Polar Frontal waters of the Antarctic Ocean.
The work is also significant on the score that it helps to build a database on microbial communities of Antarctica and to assign a unique digital identity to microorganisms.
The actinobacterial strains were identified based on their morphological (aerial mass colour, melanoid, reverse side and soluble pigments), physiological (carbon source assimilation), and chemotaxonomical characteristics (cell wall amino acid and whole-cell sugar) by following the recommended method of Shirling and Gottlieb [2], and Lechevalier and Lechevalier [3].The actinobacterial strains were warranted at genus level by comparing the data with the identification key developed by Nonomura [4].16S rRNA gene sequencing was performed to identify the taxonomic position of the actinobacterial strains.Genomic DNA was extracted [5] and amplified using using the universal bacterial primers 27f (5′-GAGTTTGATCCTGGCTCAG-3′) and 1492r (5′-TACGGCTACCTTGTTACGACTT-3′) following the PCR conditions described by Karuppiah et al. [6].The amplified products were purified using QIA quick PCR cleanup kit (Qiagen Inc., Chatsworth) and were sequenced using ABI automated sequencer (Applied Biosystems-3100) at Macrogen Inc., Republic of Korea.The forward and reverse sequences were assembled using EZ-Taxon database (https://www.ezbiocloud.net)and the sequence similarity was tested in the BLASTn program of the NCBI-GenBank database (http://www.ncbi.nlm.nih.gov/BLAST/).The phylogenetic tree was constructed to understand the actinobacterial lineage using the neighbour-joining method of Saitou and Nei [7].The topology of the phylogenetic tree was evaluated, using the bootstrap resampling method of Felsenstein [8] with 1000 replicates.

Fig. 4 .
Fig. 4. Graphical representations of G þ C content of 16S rRNA gene sequences of the psychrophilic and psychrotolerant actinobacteria.

Table 1
Digital data harbouring the unique barcode sequences of the psychrophilic and psychrotolerant actinobacteria.