Insights into the effect of a natural arsenate dose on growth, nodulation and redox metabolism of soybean plants

Abstract

Arsenic (As) constitutes a global environmental problem being groundwater the first stage of metalloid distribution in the trophic chain. Thus, soybean plants inoculated with Bradyrhizobium sp. Per 3.61 (a rhizobia that promotes As phytostabilization) were examined to elucidate the impact of a natural arsenate dose on growth and nodulation and to determine the redox metabolism response of leaves and nodules. The findings showed that metalloid reduced soybean growth and nodulation variables. Moreover, soybean leaves showed an increase of hydrogen peroxide content and Glutathione S-Transferase (GST) activity while a significant reduction of lipid peroxidation and no modification of glutathione content was observed compared to control condition. These variables were unchanged in nodules with the exception of glutathione level that was significantly reduced by As(V). Thus, a real arsenate dose modified redox state of soybean leaves inducing GST activity, even when a rhizobia that promotes phytostabilization were used as inoculant. These findings contributes to improve the understanding of the negative impact that the metalloid could have on crop yield. Moreover, considering the strong induction of GST in soybean leaves, the potential use of GST as a biomarker of As contamination at field conditions is proposed.