Isolation and characterization of marine bacteria from East Coast of India: functional screening for salt stress tolerance

Soil salinization has become a severe constraint for crop production world-wide which necessitated development or induced enhancement of salt stress tolerance in plant life to sustain production in saline lands. Recognition and prospecting of valuable stress tolerant genes from natural microbial resources of saline habitat is obscure to date. Therefore, the investigation was towards isolation and characterization of marine salt stress tolerant microbes along the East coast of India for revelation of effective salt stress tolerant genes. Salt stress tolerance was assessed from 98 bacterial isolates obtained from 28 water and soil samples. Among them, 35 isolates which failed to grow beyond 4% salt were discarded and remainder 63 isolates were selected for further functional analysis and only seven isolates recorded ≥8% NaCl stress tolerance. Phylogeny revealed that four isolates belong to Firmicutes and three isolates were members of Proteobacteria. Ribosomal Database Project Release-11 and SILVA SSU database based genotyping and taxonomic identity analysis confirmed that the higher (20%) salt stress tolerant bacteria were Staphylococcus sp., Enterococcus sp., Enterobacter sp. and Proteus sp. To investigate candidate, as well as, novel salt stress tolerant genes, the seven bacterial isolates would provide new horizon to focus on the recent developments of salinity stress tolerance. In addition, the findings evidently point out the diversity of salt stress tolerant marine bacteria in coastal Odisha and West Bengal, India.