Abstract

ISOLATION AND IDENTIFICATION OF RHIZOSPHERIC BACTERIA IN FERRALSOLS OF TITHONIA (TITHONIA DIVERSIFOLIA (HAMSL.) GRAY) IN DAKNONG AND DAKLAK PROVINCE(S), VIETNAM

Prof. Dr. Cao Ngoc Diep* and Assoc. Dr. Truong Trong Ngon

ABSTRACT

Total of 32 rhizopheric bacterial isolates were isolated from 5 ferralsols samples of tithonia at two provinces (DakNong and DakLak) of western highland of Vietnam. All of them had the ability of ammonium synthesis, phosphate solubilization and IAA biosynthesis however they had the big potential of phosphate solubilization. The sequences from selected nitrogen-fixing and phosphate-solubilizing bacteria (17 isolates) showed high degrees of similarity to those of the GenBank references strains (between 98% and 99%). From 17 isolates, 9 belonged to Bacilli, while 3, 3 and 2 were Alpha, Beta, Gamma- Proteobacteria, respectively. Based on Pi value (nucleotide diversity), Bacilli group had the highest theta value and Theta values (per sequence) from S of SNP for DNA polymorphism were calculated for each group and Bacilli group had the highest values in comparison to three groups. There were 19/32 isolates producing siderophores. From these results showed that two strains (Bacillus subtilis SDN2c and Burkholderia pyrrocinia SDN31) revealed promising candidates with multiple beneficial characteristics (high phosphate solubilization) and they have the potential for application as inoculants adapted to poor soils and many kinds of crop because they are not only famous strains but also are safety strains for agricultural sustainable.

Keywords: 16S rRNA Gene Sequence, Ferrasols, Nitrogen-Fixing Bacteria, Phosphate-Solubilizing Bacteria, Rhizosphere, Tithonia.