Promoter driven expression in rice enhances arsenic phytoextraction in paddy soils.

Arsenic (As) contamination in paddy soils is a global problem, threatening rice production and food safety. Hyperaccumulator plants have garnered significant attention for their potential to remove pollutants from contaminated soil. However, no natural hyperaccumulators have been found for the phytoremediation of As-contaminated paddy soils under flooding conditions. One promising strategy is to genetically engineer (rice) to hyperaccumulate As for effective phytoremediation of paddy soil. A key challenge remains in increasing metal accumulation without compromising tolerance. Here, from the As hyperaccumulator was introduced under the control of a rice root-specific promoter to create high-As-accumulating and tolerant transgenic remediation rice. The remediation rice strains exhibited robust growth, with shoot As concentration reaching up to 451-557 ​mg/kg in a hydroponic experiment with 20 ​μM NaAsO treatment, and 45.9-80.3 ​mg/kg in pot experiments with moderately As-contaminated paddy soils. Compared to wild-type rice, the transgenic rice removed 23.5 times more As from the same paddy soils. By harvesting rice shoots before grain filling, the soil pore water As was almost completely depleted, and the acid-soluble and reducible fractions of As were significantly reduced. This study presents the first transgenic remediation rice characterized by high As accumulation, tolerance, and adaptability to paddy soils under flooding conditions for effective phytoremediation.