Isolation and identification of endophytic bacteria associated with Rhizophora mucronata and Avicennia alba of Nam Can district, Ca Mau Mangrove Ecosystem

Abstract

A total of 86 endophytic bacterial isolates were isolated from 12 plant samples of two kinds of mangroves at Nam Can district, Ca Mau Peninsula (Ca Mau province, Mekong Delta of Vietnam). All of them showed the potential abilities of ammonium synthesis, phosphate solubilization, and excellent IAA biosynthesis. Especially, while all of the strains tolerated at a concentration of 4% NaCl, 17 bacterial isolates demonstrated a large salt tolerance ranging from 4.5 to 7%. 5 isolates regarding to the best of ability in nitrogen fixation, phosphate solubilization, IAA biosynthesis, siderophores and high salt tolerance were chosen to sequence and the results showed high degrees of similarity to those of the GenBank reference strains (99%). There were 3/5 strains belonged to Bacilli, and 2/5 strains were Gamma-Proteobacteria. Whereas our results showed that there were some good strains for nitrogen fixation, the strain Enterobacter cloacae NDNC1e revealed as a promising candidate with multiple beneficial characteristics (good nitrogen fixation, phosphate solubilization, IAA biosynthesis and high salt tolerance). Besides, the isolated bacterial strain has the potential for application as inoculants adapted to many kinds of crops grown on poor and saline soils because it is not only famous strain, but also safe strain for sustainable agriculture in “sea level rise”condition. Keywords: 16S rRNA Gene Sequence, Mangrove Endophytic Bacteria, Nitrogen Fixation, Phosphate Solubilization, IAA, siderophores, soil salinity