Agrochemical Oryzemate treatment controls the uptake of hydrophobic organic pollutants through the regulation of major latex-like proteins

Abstract

The Cucurbitaceae family accumulates hydrophobic organic pollutants in their aerial parts at high concentrations. Major latex-like proteins (MLPs) identified in Cucurbita pepo bind to hydrophobic organic pollutants in roots, forming complexes that are transported via xylem vessels to the plant’s aboveground parts. However, soil remediation of hydrophobic organic pollutants utilizing MLPs has not been established. In this study, the uptake of hydrophobic organic pollutants was promoted by C. pepo through the upregulation of MLP genes by agrochemical treatment. It was found that probenazole, an active ingredient in the agrochemical Oryzemate, upregulated the promoter activity of MLP genes in the roots of transgenic tobacco plants. Oryzemate treatment increased the amount of MLPs in the roots and xylem sap of C. pepo. Oryzemate treatment slightly increased and significantly decreased the concentration of the hydrophobic organic pollutant pyrene in the xylem sap of C. pepo cultivated in high- and low-contamination soils, respectively. Probenazole competitively inhibits the binding of MLPs to pyrene, thereby suppressing its uptake by C. pepo in low-contamination soil. This study demonstrates that Oryzemate possesses dual effects: effective phytoremediation and safe crop production, depending on the soil contamination level.