Natural variation in arsenate tolerance identifies an arsenate reductase in Arabidopsis thaliana

Abstract

The enormous amount of environmental arsenic was a major factor in determining the biochemistry of incipient life forms early in the Earth's history. The most abundant chemical form in the reducing atmosphere was arsenite, which forced organisms to evolve strategies to manage this chemical species. Following the great oxygenation event, arsenite oxidized to arsenate and the action of arsenate reductases became a central survival requirement. The identity of a biologically relevant arsenate reductase in plants nonetheless continues to be debated. Here we identify a quantitative trait locus that encodes a novel arsenate reductase critical for arsenic tolerance in plants. Functional analyses indicate that several non-additive polymorphisms affect protein structure and account for the natural variation in arsenate reductase activity in Arabidopsis thaliana accessions. This study shows that arsenate reductases are an essential component for natural plant variation in As(V) tolerance.

Cytokinin determines thiol-mediated arsenic tolerance and accumulation in Arabidopsis thaliana

“…Root meristem activity can be restored by removing As(V) from the medium. Root growth recovery depends on the function of an As(V) reductase that is essential for arsenic detoxification (Sánchez-Bermejo et al, 2014), which supports the idea that plants are able to integrate arsenic tolerance mechanisms 1418 …”

“…Root meristem activity can be restored by removing As(V) from the medium. Root growth recovery depends on the function of an As(V) reductase that is essential for arsenic detoxification (Sánchez-Bermejo et al, 2014), which supports the idea that plants are able to integrate arsenic tolerance mechanisms into developmental programs. In general, phytohormones are involved in reconfiguration of developmental patterns in response to abiotic stress (Peleg and Blumwald, 2011;Zwack and Rashotte, 2015), although their role in arsenicmediated growth control is currently unknown.…”

“…3). Since As(III) is necessary for PC biosynthesis and accumulation, the action of As(V) reductases is essential for As(V) tolerance in plants (Bleeker et al, 2006); we thus also analyzed expression of the recently identified As(V) reductase gene AtARQ1/HAC1 (Chao et al, 2014;Sánchez-Bermejo et al, 2014). qRT-PCR expression analysis of Figure 2.…”

“…In addition, As(III) activates GSH and PC accumulation; As(V) reductase activity is thus essential for arsenic tolerance (Bleeker et al, 2006). Arabidopsis thaliana ARSENATE REDUCTASE QTL1 (AtARQ1, At2g21045; also termed HAC1; Chao et al, 2014), an As(V) reductaseencoding gene, is also transcriptionally regulated by As(V) (Sánchez-Bermejo et al, 2014). Arsenic tolerance thus requires coordinated expression of several As(V)-responsive genes involved in As(V) reductase activity and PC accumulation.…”

Naming and functions of ACR2, arsenate reductase, and ACR3 arsenite efflux transporter in plants (correspondence on: Kumar, S., Dubey, R.S., Tripathi, R.D., Chakrabarty, D., Trivedi, P.K., 2015. Omics and biotechnology of arsenic stress and detoxification in plants: current updates and prospective. Environ Int. 74:221–230.)

“…Recently, a quantitative trait locus that encodes a novel arsenate reductase critical for arsenic tolerance in plants was identified independently by two research groups. This arsenate reductase lacks HCX 5 R and was termed ATQ1 (Arsenate Tolerance QTL1) (also called ARQ1 for Arsenate Reductase QTL1) and HAC1 (High Arsenic Content 1), respectively (Chao et al, 2014;Sanchez-Bermejo et al, 2014). This arsenate-reducing enzyme controls arsenic accumulation in plants and keeps arsenic low in the shoots, which provides an important new resource to engineer low-As rice (Meadows, 2014).…”