Characterization of bacteria community associated with soil arsenic and sulphate contamination based on 16S rRNA gene sequences

Abstract:

In order to investigate molecular diversity of bacteria community from both a normal arable soil (Nor-1) and an arsenic and sulphate polluted soil (Sul-1). Environmental total DNA was directly extracted from two soil samples. The 16S rRNA genes were amplified from the total DNA and construction a clone library. Positive clones were randomly selected from the library and identified by amplified ribosomal DNA restriction analysis (ARDRA) and sequencing, then constructed phylogenetic tree. 23 unique clone sequences from Nor-1 soil were classified into 5 bacterial phylum including Acidobacteria (12.3%, 8/65), Actinobacteria(3.1%, 2/65), Firmicutes (21.5%, 14/65), Nitrospira (3.1%, 2/65) and Proteobacteria (60%, 39/65), while 19 unique clone sequences from Sul-1 soil were classified into 2 bacterial phylum including Firmicutes (29.5%, 13/44), and Proteobacteria (70.5%, 31/44). The result suggested that the high concentration of arsenic and sulphate influenced the bacterial population of Sul-1 soil leading to construction of obviously specific bacteria community. Interestingly, a lot of Acinetobacter related sequences have been detected in Sul-1 soil bacteria community including clone Sul11/15, Sul12/7 and Sul12/11. Because Acinetobacter strains are often ubiquitous, exhibit metabolic versatility, those related strains may be good targets for exploiting novel arsenic detoxification bacteria.