[Isolation and biodiversity of heavy metal tolerant endophytic bacteria from halotolerant plant species located in coastal shoal of Nantong].

OBJECTIVE

We isolated and identified endophytic bacteria from halotolerant plants collected from coastal shoal of Nantong and investigated their heavy-metal tolerance and plant growth promoting potential.

METHODS

In total 45 strains were obtained from 4 halotolerant plants and 23 representative isolates were selected to detect their tolerance against NaCl and heavy metals of Cu2+, Pb2+, Cd2+, Zn2+, Hg2+; plant growth promoting index of nitrogen fixation, phosphate solubilization, indoleacetic acid (IAA) production and 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase.

RESULTS

Most of the isolates could grow under high consistency of Cu2+ and Pb2+. Of the bacteria 26.1% had the ability of nitrogen fixation, 21.7% of phosphate solubilization, 60.9% of IAA production and 39.1% of ACC deaminase activity. The results of 16S rRNA sequencing show that they belonged to the genera of Bacillus, Halobacillus, Oceanobacillus, Exiguobacterium, Serratia, Brevundimonas, Vibrio and Staphylococcus. Among them, strains KLBMP 2432 and KLBMP 2447 were potential novel species.

CONCLUSION

The halotolerant plants located in the area of coastal shoal contain a variety of endophytic bacteria as well as the source of novel taxa. Some of them had the ability of plant growth promoting and high resistance against heavy-metal Cu2+ and Pb2+.