Functional Screening and Molecular Characterization of Halophilic and Halotolerant Bacteria by 16S rRNA Gene Sequence Analysis
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A total of 206 bacterial isolates were obtained from soil, water and sediment samples using three different culture media with a pH of 7.3 ± 0.2 and an incubation temperature of 37 °C. Of these isolates, 48 bacteria were selected for functional screening and molecular characterization. The functional screening for salt stress tolerance revealed that, 17 bacteria were identified as moderately halotolerant and 31 were halophilic, capable of growing at 5–15 % (w/v) and ≥15 % (w/v) of NaCl concentration respectively. The 16S rRNA gene sequence analysis and taxonomic identification of isolates were performed using Ribosomal Database Project Release-10 and SILVA SSU database. Based on the sequence length >1,300 bp, 40 bacteria were identified out of 48 isolates. Study showed that, Staphylococcus spp. was highly resistant to salt stress followed by Enterococcus faecalis, Vagococcus fluvialis and Vibrio parahaemolyticus. The phylogenetic analysis revealed that, 24 bacterial isolates belong to Firmicutes and 16 isolates come under Proteobacteria. These bacterial strains would be of great use for prospecting novel and candidate salt stress tolerant genes.
KeywordsHalophilic and halotolerant bacteria 16S rRNA gene Salt stress tolerance Molecular characterization
Authors are greatly indebted to Dr. S. Ayyappan, Secretary, DARE and DG, ICAR, New Delhi, Dr. T. Mohapatra, Director, CRRI, Cuttack, and Dr. N. K. Singh, National Professor, NRCPB, New Delhi for their encouragement and support. This work was supported financially by the World Bank funded NAIP Project of ICAR on, “Bioprospecting of genes and allele mining for Abiotic stress tolerance”. The laboratory assistance by Mr. Asim Kumar Jana and Sk. Rabiul are duly acknowledged.
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