New arsenate reductase gene (arrA) PCR primers for diversity assessment and quantification in environmental samples.


The extent of arsenic contamination in drinking water and its potential threat to human health have resulted in considerable research interest in the microbial species responsible for arsenic reduction. The arsenate reductase gene (arrA), an important component of the microbial arsenate reduction system, has been widely used as a biomarker to study arsenate-reducing microorganisms. A new primer pair was designed and evaluated for quantitative PCR (qPCR) and high-throughput sequencing of the arrA gene, because currently available PCR primers are not suitable for these applications. The primers were evaluated in silico and empirically tested for amplification of arrA genes in clones and for amplification and high-throughput sequencing of arrA genes from soil and groundwater samples. In silico, this primer pair matched (≥90% DNA identity) 86% of arrA gene sequences from GenBank. Empirical evaluation showed successful amplification of arrA gene clones of diverse phylogenetic groups, as well as amplification and high-throughput sequencing of independent soil and groundwater samples without preenrichment, suggesting that these primers are highly specific and can amplify a broad diversity of arrA genes. The arrA gene diversity from soil and groundwater samples from the Cache Valley Basin (CVB) in Utah was greater than anticipated. We observed a significant correlation between arrA gene abundance, quantified through qPCR, and reduced arsenic (AsIII) concentrations in the groundwater samples. Furthermore, we demonstrated that these primers can be useful for studying the diversity of arsenate-reducing microbial communities and the ways in which their relative abundance in groundwater may be associated with different groundwater quality parameters.



Document Type





arsenate reductase gene (arrA), high-throughput sequencing, qPCR of arrA gene, arsenic reduction

Publication Date


Journal Title

Applied Environmental Microbiology