Executive Summary : | Rice is the second most important cereal crop in the world and is the primary food for half of the world. Heavy metal(loid) toxicity has emerged as one of the major constraints affecting rice productivity and quality. Presences of these metal(loid)s above threshold level in the edible parts cause toxicity to the herbivores including human beings. Amidst the different heavy metal(loid), arsenic (As) show significant bioaccumulation in rice and acts as a significant contributor of dietary As intake and function as a major risk factor for several human diseases. Several approaches including biotechnological interventions using single critical genes have been undertaken to reduce the grain As content of rice; however none of the adopted tactics have produced “zero-As” rice grain. Thus, considering the serious threat posed by As-accumulation in rice grains, a multigenic approach involving root-specific overexpression of Arsenate reductase and C-type ATP-binding cassette transporter along with simultaneous constitutive downregulation of arsenite efflux is being proposed. The novel strategy will not only ensure the complete reduction of As(V) to As(III) in rice roots leading to enhanced influx; but also the xylem loading and intervascular transfer of As(III) will be hampered leading to trapping of As in the rhizosphere of the rice resulting in significantly less accumulation in the grains. A successful completion of the project is expected to produce safer near zero-As rice grains. |