Thioarsenate Toxicity and Tolerance in the Model System Arabidopsis thaliana.
Thioarsenate Toxicity and Tolerance in the Model System Arabidopsis thaliana.
复制标题
DOI：
10.1021/acs.est.6b06028
复制
发表时间：
2017-06
影响因子：
11.4
通讯作者：
B. Planer-Friedrich;Tanja Kühnlenz;Dipti Halder;Regina Lohmayer;N. Wilson;Colleen F. Rafferty;S. Clemens
中科院分区：
文献类型：
--
作者：
B. Planer-Friedrich;Tanja Kühnlenz;Dipti Halder;Regina Lohmayer;N. Wilson;Colleen F. Rafferty;S. Clemens
硫代砷酸盐在硫酸盐还原条件下由亚砷酸盐形成，例如，在水稻土中，是砷酸盐的结构类似物。尽管水稻是人类砷摄入量的最重要来源之一，但没有关于植物对硫代砷酸盐的吸收、毒性或耐受性的报道。使用拟南芥模型系统的实验表明，一硫代砷酸盐的毒性低于亚砷酸盐，但在≥25 μM As的浓度下比砷酸盐的毒性更大，反映在琼脂平板上更强的幼苗生长抑制。尽管较高的毒性，总砷积累在根暴露于monothioarsenate相比，砷酸盐，更高的根外排被证实。根冠易位是高于单硫代砷酸比砷酸盐。与野生型（Col-0）相比，砷酸盐和单硫代砷酸盐在植物螯合素（PC）缺陷突变体（cad 1 -3）以及谷胱甘肽生物合成（cad 2）和PC转运（abcc 12）突变体中诱导更高的毒性，这表明PC途径不仅对砷酸盐，而且对单硫代砷酸盐解毒具有重要作用。在Col-0中，单硫代砷酸盐比砷酸盐诱导相对较高的PC积累。所观察到的植物吸收，毒性和耐受性的硫代砷酸盐与氧砷酸盐的差异表明，研究砷对植物的影响，应包括实验与巯基化的物种。
Thioarsenates form from arsenite under sulfate-reducing conditions, e.g., in rice paddy soils, and are structural analogues of arsenate. Even though rice is one of the most important sources of human arsenic intake, nothing is published about uptake, toxicity, or tolerance of thioarsenates in plants. Experiments using the model system Arabidopsis thaliana showed that monothioarsenate is less toxic than arsenite, but more toxic than arsenate at concentrations ≥25 μM As, reflected in stronger seedling growth inhibition on agar plates. Despite higher toxicity, total As accumulation in roots was lower upon exposure to monothioarsenate compared to arsenate, and a higher root efflux was confirmed. Root-shoot translocation was higher for monothioarsenate than for arsenate. Compared to the wild type (Col-0), both arsenate and monothioarsenate induced higher toxicity in phytochelatin (PC)-deficient mutants (cad1-3) as well as in glutathione biosynthesis (cad2) and PC transport (abcc12) mutants, demonstrating the important role of the PC pathway, not only for arsenate, but also for monothioarsenate detoxification. In Col-0, monothioarsenate induced relatively higher accumulation of PCs than arsenate. The observed differences in plant uptake, toxicity, and tolerance of thioarsenate vs oxyarsenate show that studying the effects of As on plants should include experiments with thiolated As species.