Impact of Arsenite on the Bacterial Community Structure and Diversity in Soil

Abstract

The impact of arsenite (As[III]) on the bacterial community structure and diversity in soil was determined by incubating soil slurries with 50, 500, and 5,000 μM As(III). As(III) was oxidized to arsenate (As[V]), and the microbial contribution to As(III) oxidation was 70–100%. PCR-denaturing gradient gel electrophoresis revealed that soil bacterial diversity decreased in the presence of As(III). Bacteria closely related to the family Bacillaceae were predominant in slurry spiked with 5,000 μM As(III). The population size of culturable As(III)-resistant bacteria was 37-fold higher in this slurry than in unspiked slurry (p < 0.01), indicating that high levels of As(III) stimulate the emergence of As(III)-resistant bacteria. As(III)-resistant bacteria isolated from slurry spiked with 5,000 μM As(III) were mainly affiliated with the genus Bacillus; however, no strains showed As(III)-oxidizing capacity. An As(III)-oxidizing bacterial community analysis based on As(III) oxidase gene (aioA) sequences demonstrated that diversity was the lowest in slurry spiked with 5,000 μM As(III). The deduced AioA sequences affiliated with Alphaproteobacteria accounted for 91–93% of all sequences in this slurry, among which those closely related to Bosea spp. were predominant (48–86%). These results suggest that exposure to high levels of As(III) has a significant impact on the composition and diversity of the soil bacterial community, including the As(III)-oxidizing bacterial community. Certain As(III)-oxidizing bacteria with strong As(III) resistance may be enriched under high As(III) levels, while more sensitive As(III) oxidizers are eliminated under these conditions.

Exploring Biodiversity and Arsenic Metabolism of Microbiota Inhabiting Arsenic-Rich Groundwaters in Northern Italy

“…Sequences obtained from site I and from site L were related to uncultivated bacteria from different As-contaminated mines or sediments (95–99%, Quéméneur et al, 2008; Heinrich-Salmeron et al, 2011; Yamamura and Amachi, 2014). Finally, clone 55 from site L formed a cluster with the aioA of an uncultivated bacterium (97% to BAP99953) from enrichment cultures with As(III)-spiked paddy soil (Dong et al, 2016) and with the sequence of Nitrobacter hamburgensis X14, a facultative chemolithoautotroph bacterium (Muller et al, 2007). The cluster associated with Betaproteobacteria was related (81–96% identity) to members of the order Burkholderiales .…”

Detection of arsenite-oxidizing bacteria in groundwater from a gold mine under different geochemical environments

“…RA-1SW(1), RA-1soil(7), and MA-3(10) were similar to uncultured bacterium aioA gene, clone N-4d5 isolated from sediments in Japan (AB730976, AB731084 and AB838863; (Yamamura et al, 2014). MA-3(7) were closely related to uncultured bacterium aioA gene, clone Aio_aoxBM1-2F/3-2R_L-32 retrieved from soils (LC012221; (Dong et al, 2016). Phylogenetic analysis also showed that arsenite-oxidizing bacteria recovered from samples MA-1soil(2), MA-1soil(17), RA1-1, and MA-1soil(10) were related to uncultured bacterium clone Q6429-2-15 arsenite oxidase (aroA) gene from rhizophere (KP726747, KP726558 and KP726744) ( (Han et al, 2015).…”