Heterologous expression of the yeast arsenite efflux system ACR3 improves Arabidopsis thaliana tolerance to arsenic stress

• Published in: The New phytologist Vol. 194; no. 3; pp. 716 - 723
• Main Authors: Ali, Waqar, Isner, Jean‐Charles, Isayenkov, Stanislav V., Liu, Wenju, Zhao, Fang‐Jie, Maathuis, Frans J. M.
• Format: Journal Article
• Language: English
• Published: Oxford, UK New Phytologist Trust 01.05.2012; Blackwell Publishing Ltd; Wiley Subscription Services, Inc
• Subjects: ACR3; Arabidopsis; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis - physiology; Arabidopsis thaliana; arsenate; Arsenates; Arsenates - metabolism; Arsenic; Arsenic - analysis; Arsenic - metabolism; Arsenite; Arsenites; Arsenites - metabolism; Biological Transport; Cell Membrane - metabolism; Cell membranes; Contamination; Efflux; Extrusion; Hydroponics; Membrane Transport Proteins - genetics; Membrane Transport Proteins - metabolism; Plant growth; Plant roots; Plant Roots - genetics; Plant Roots - metabolism; Plant Roots - physiology; Plant Shoots - genetics; Plant Shoots - metabolism; Plant Shoots - physiology; Plant tissues; Plants; Plants, Genetically Modified; Pollution tolerance; Protoplasts; Recombinant Fusion Proteins; Rice; Saccharomyces cerevisiae; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - metabolism; Seedlings; Seedlings - genetics; Seedlings - metabolism; Seedlings - physiology; Shoots; Stress, Physiological - genetics; Tissue; Transformation, Genetic; Transgenes; Transgenic plants; Translocation; Yeast; Yeasts
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/j.1469-8137.2012.04092.x

Arsenic contamination has a negative impact on crop cultivation and on human health. As yet, no proteins have been identified in plants that mediate the extrusion of arsenic. Here, we heterologously expressed the yeast (Saccharomyces cerevisiae) arsenite efflux transporter ACR3 into Arabidopsis to evaluate how this affects plant tolerance and tissue arsenic contents. ACR3 was cloned from yeast and transformed into wild-type and nip7;1 Arabidopsis. Arsenic tolerance was determined at the cellular level using vitality stains in protoplasts, in intact seedlings grown on agar plates and in mature plants grown hydroponically. Arsenic efflux was measured from protoplasts and from intact plants, and arsenic levels were measured in roots and shoots of plants exposed to arsenate. At the cellular level, all transgenic lines showed increased tolerance to arsenite and arsenate and a greater capacity for arsenate efflux. With intact plants, three of four stably transformed lines showed improved growth, whereas only transgenic lines in the wild-type background showed increased efflux of arsenite into the external medium. The presence of ACR3 hardly affected tissue arsenic levels, but increased arsenic translocation to the shoot. Heterologous expression of yeast ACR3 endows plants with greater arsenic resistance, but does not lower significantly arsenic tissue levels.