Isolation of salt-tolerant bacteria from rhizosphere and rhizoplane of halophyte plant Suaeda japonica in Gochang·Buan tidal flat

Nine strains of high concentrations of salt-tolerant bacteria were isolated from the rhizosphere and rhizoplane of the halophyte plant Suaeda japonica grown in Gochang · Buan tidal flat. The isolated bacteria were classified as genera Vibrio (strains JRS-1, -2, -3, -4, and -5, and JRL-1 and -4) and Bacillus (strains JRL-2 and -3) based on the 16S rRNA gene sequence similarity. The optical growth condition for salt concentration was examined on the selected, representative strains. Strain JRS-1 with the closest relative of Vibrio neocaledonicus showed the highest growth rate at the total salt concentration of 6% among the incubation conditions of 3-8% salt concentrations. Strain JRL-2 with the closest relative of Bacillus thuringiensis showed the tendency that growth rate increased with increasing salt concentrations and the maximum growth rate at 7% of the total salt concentration. The isolated bacteria showed salt-resistances to higher salt concentrations than their habitat soils with 3%. In addition, we identified evidences of potentially plant interaction-relevant enzymatic activities, from utilization of some substrates rich in plants, such as triglyceride, ρ-nitrophenyl-α,D-glucoside, and ρ-nitrophenyl-β,D-glucoside.