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

Abstract:

Abstract:［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+．

Key words:Keywords: halotolerant plants，endophytic bacteria，heavy metal，plant growth promoting，biodiversity