Phylogenetic Diversity of Endophytic Moderately Halophilic Bacteria Isolated from Suaeda salsa L.

Abstract:

The traditional isolation and identification method and analysis based on 16S rRNA sequences were used to investigate the phylogenetic diversity of endophytic moderately halophilic bacteria of Suaeda salsa L. in Dongying. According to physiological and biochemical characteristics, 16S rRNA sequences and phylogenetic analysis, 15 isolated endophytic bacterial strains were classified into four groups, belonging to genera Chromohalobacter, Kushneria, Halomonas or Bacillus separately. 16S rRNA sequences of 4 strains in Group I had the highest similarity to Chromohalobacter israelensis (95%). Group II which contained 7 strains of the genus Kushneria is the dominant group in Suaeda salsa L.. The strains in Group III bear the closest affiliation to Haererehalobacter sp. JG 11 (99%), which is not classified definitely. The only endospore-forming bacterium was classified into group IV. Its 16S rRNA sequence similarities with respect to the known Bacillus species were ≤ 96%, which was presumed to be potential novel species. Among these isolated strains, 3 strains produced proteinase; 14 strains produced esterase; 8 strains produced DNase; 11 strains produced galactosidase; 14 strains produced urease. The research results indicated that there was not only abundant phylogenetic diversity of moderately halophilic bacteria, but also some unknown bacteria groups existed in Suaeda salsa L..