Arsenic uptake and metabolism in arsenic resistant and nonresistant plant species

Abstract

SummaryElevation of arsenic levels in soils causes considerable concern with respect to plant uptake and subsequent entry into wildlife and human food chains. Arsenic speciation in the environment is complex, existing in both inorganic and organic forms, with interconversion between species regulated by biotic and abiotic processes. To understand and manage the risks posed by soil arsenic it is essential to know how arsenic is taken up by the roots and metabolized within plants. Some plant species exhibit phenotypic variation in response to arsenic species, which helps us to understand the toxicity of arsenic and the way in which plants have evolved arsenic resistances. This knowledge, for example, could be used produce plant cultivars that are more arsenic resistant or that have reduced arsenic uptake. This review synthesizes current knowledge on arsenic uptake, metabolism and toxicity for arsenic resistant and nonresistant plants, including the recently discovered phenomenon of arsenic hyperaccumulation in certain fern species. The reasons why plants accumulate and metabolize arsenic are considered in an evolutionary context. © New Phytologist (2002) 154 : 29 -43

First evidence on different transportation modes of arsenic and phosphorus in arsenic hyperaccumulator Pteris vittata

“…However, Meharg and Hartley-Whitaker (2002) have proposed that the role of the P transporter may be limited in As hyperaccumulation because hyperaccumulators can accumulate not only arsenate (As(V)), but also arsenite (As(III)) and organic As. Although Mathews et al (2010) suggested that, before entering into plants, As(III) may be oxidized into As(V) by microorganisms around P. vittata's rhizoids, the available references do not fully explain the role of a P transporter in the transport of As(V) and As(III).…”

The arbuscular mycorrhizal fungus Glomus mosseae can enhance arsenic tolerance in Medicago truncatula by increasing plant phosphorus status and restricting arsenate uptake

“…Plants growing on arsenic polluted soils tend to be mycorrhizal (Meharg and Hartley-Whitaker, 2002) and mycorrhizal fungi may therefore be important in re-vegetation or phytostabilization. Hymenoscyphus ericae, an ericoid mycorrhizal fungus, has co-evolved with its host plant, Calluna vulgaris, to resist As toxicity (Sharples et al, 2000a(Sharples et al, ,b,2001).…”

“…Ahmed et al (2006) showed that inoculation with G. mosseae lowered As concentrations in shoots and roots of lentil and the fungus may have promoted P uptake but excluded arsenic. The mechanisms by which AM fungi influence the relationship between arsenate resistance and arsenate/phosphate uptake are yet to be elucidated (Meharg and Hartley-Whitaker, 2002). Here, we attempted to acquire more information on the possible enhancement of plant arsenate tolerance by AM colonization.…”

Arsenic accumulation and speciation in the submerged macrophyte Ceratophyllum demersum L.

“…Additionally, people can also suffer from As toxicity through consumption of rice and vegetables irrigated with As-tainted water (Meharg and Hartley-Whitaker 2002;Tripathi et al 2007;Zhu et al 2008). Therefore, it is an urgent need to reduce As contamination in water.…”

“…As for non-hyperaccumulating plants, several studies on terrestrial plants suggested that arsenate and arsenite enter plant cells via phosphate transporters and aquaglycerolporin channels, respectively (Abedin et al 2002;Meharg and Hartley-Whitaker 2002;Meharg and Jardine 2003). In addition, the reduction of arsenate and complexation of arsenite by thiol peptides are considered to be important mechanisms of As detoxification Zhao et al 2009).…”