Heterologous Expression of Pteris vittata Arsenite Antiporter PvACR3;1 Reduces Arsenic Accumulation in Plant Shoots

Abstract

Arsenic (As) is a toxic carcinogen so it is crucial to decrease As accumulation in crops to reduce its risk to human health. Arsenite (AsIII) antiporter ACR3 protein is critical for As metabolism in organisms, but it is lost in flowering plants. Here, a novel ACR3 gene from As-hyperaccumulator Pteris vittata, PvACR3;1, was cloned and expressed in Saccharomyces cerevisiae (yeast), Arabidopsis thaliana (model plant), and Nicotiana tabacum (tobacco). Yeast experiments showed that PvACR3;1 functioned as an AsIII-antiporter to mediate AsIII efflux to an external medium. At 5 μM AsIII, PvACR3;1 transgenic Arabidopsis accumulated 14-29% higher As in the roots and 55-61% lower As in the shoots compared to WT control, showing lower As translocation. Besides, transgenic tobacco under 5 μM AsIII or AsV also showed similar results, indicating that expressing PvACR3;1 gene increased As retention in plant roots. Moreover, observation of PvACR3;1-green fluorescent protein fusions in transgenic Arabidopsis showed that PvACR3;1 protein localized to the vacuolar membrane, indicating that PvACR3;1 mediated AsIII sequestration into vacuoles, consistent with increased root As. In addition, soil experiments showed ∼22% lower As in the shoots of transgenic tobacco than control. Thus, our study provides a potential strategy to limit As accumulation in plant shoots, representing the first report to decrease As translocation by sequestrating AsIII into vacuoles, shedding light on engineering low-As crops to improve food safety.

Metal resistant PGPR lowered Cd uptake and expression of metal transporter genes with improved growth and photosynthetic pigments in Lycopersicon esculentum under metal toxicity

“…The results observed by them in yeast indicated that PvACR3; 1 is a well developed antiporter that efflux As into the medium. Moreover, they also found that Arabidopsis thaliana and Nicotiana tabacum accumulated higher levels of As and reduced their accumulation in shoots 75 .…”

“…A study conducted by Chen et al . showed that cloning of As- antiporter ACR3 Pteris vittata , PvACR3; 1 was done and expressed in Arabidopsis thaliana and Nicotiana tabacum and yeast 75 . The results observed by them in yeast indicated that PvACR3; 1 is a well developed antiporter that efflux As into the medium.…”

The roles of membrane transporters in arsenic uptake, translocation and detoxification in plants

“…Further studies show that overexpression of PvACR3 in Arabidopsis greatly increased As(III) translocation from roots to shoots, suggesting that PvACR3 functions as a plasma membrane efflux transporter involved in the xylem loading of As(III) (Wang et al, 2018). Different from PvACR3, PvACR3;1 was localized to the vacuolar membrane when the gene was heterologously expressed in Arabidopsis and tobacco (Chen, Hua et al, 2017). Also, contrary to PvACR3, expressing PvACR3;1 in Arabidopsis and rice greatly decreased As(III) translocation from roots to shoots, probably by sequestering As(III) into the vacuoles (Chen, Hua et al, 2017;Chen, Hua et al, 2019).…”

Phytoremediation Potential, Photosynthetic and Antioxidant Response to Arsenic-Induced Stress of Dactylis glomerata L. Sown on Fly Ash Deposits

“…Furthermore, disruption of inositol transporters (AtINT2 and AtINT4) can decrease As concentrations in phloem and subsequently decrease As content in leaves [120]. Also, As(III) antiporter PvACR3;1 mediated in it sequestration into vacuoles increasing As concentrations in roots (14-29%) and decreasing its content in shoots (55-61%) [121]. Knockout of OsABCC1 transporter (ATP-binding cassette, ABC) can limit As transport and accumulation in the shoots [122].…”