Genetic Bioaugmentation of Oryza sativa to Facilitate Self-Detoxification of Arsenic In-Situ

Arsenic accumulation in rice, the world's popular grain crop, is becoming increasingly problematic because of the repeated use of arsenic-laden groundwater for cultivation. The World Health Organization reports that arsenic contamination of soil is a global issue, threatening the health of over 150 million people worldwide. Therefore, it is vital to prevent arsenic accumulation in the rice grain while simultaneously remediating arsenic from the soil. We hypothesized that if we genetically modified the rice plants using arsenic-resistant genes, then these rice plants would not only uptake arsenic from soil, but also be able to self-detoxify arsenic and thus be safe to consume. In order to test the hypothesis, we transformed rice cotyledons with acr3 and arsC arsenic resistance genes using Agrobacterium tumefaciens. Transgenic rice plants were then grown in soil contaminated with 25 ppm arsenic. After four weeks, we observed a decline in soil arsenic from 25 ppm to 10 ppm. We also observed that the arsenic in the stem of transgenic rice plants to be less than one ppm compared to 6 ppm in non-transgenic rice plants, and arsenic was undetectable in the leaves of transgenic rice plants compared to 4 ppm in non-transgenic plants. We used the ANOVA test to assess the statistical significance. Therefore, phytoremediation, a technique using plants to clean environmental pollutants and utilizing rice plants transformed with arsenic-resistant genes, is a promising method for decontaminating polluted soil. It can significantly lower arsenic accumulation in the world's popular grain crop, thus potentially reducing serious health risks.