Research Projects

Arsenic (As) contamination has emerged as a major concern in recent decades due to its toxicity to humans and animals. Even at low concentrations, As is classified as a Group 1 carcinogen by the International Agency for Research on Cancer. Chronic exposure primarily occurs through contaminated drinking water and the food chain, with nearly 40% of the total As burden in the human body attributed to dietary intake. Arsenic enters the food chain when crop plants absorb it from contaminated soil or when irrigation water contains high As levels. The eastern Indo-Gangetic plains (EIGP) are among the worst-affected regions in India, facing severe As contamination. Studies indicate that in these endemic areas, As exposure through food surpasses that from drinking water. Rice, a staple food in this region, has been identified as the primary dietary source of As, accumulating 51 µg kg-1, far exceeding the WHO’s permissible limit of 1.0 mg kg-1. Notably, rice plants absorb nearly 10 times more As than other cereals, mainly due to increased bioavailability in flooded conditions and their efficient As uptake system. Given the significance of rice cultivation in the EIGP, the accumulation of As in grains poses a severe health risk to consumers, making As contamination in rice a critical national concern. Thus, developing low-As accumulating rice that maintain yield and nutritional quality is essential to reducing As intake in this region. Additionally, climate change-driven increases in soil temperature have been shown to enhance As uptake in rice, further exacerbating the problem. Developing rice cultivars with reduced As accumulation will be a crucial step toward ensuring food security in the face of both population growth and climate change. Arsenic exists in the environment primarily in two inorganic forms: trivalent arsenite (AsIII; H2AsO3-) and pentavalent arsenate (AsV; HAsO42-). In flooded paddy fields, AsIII, the predominant form of arsenic, is inadvertently taken up through low silicon 1 (OsLsi1), a member of the Nodulin-26-like Intrinsic Protein (OsNIP2;1) aquaporin family, responsible for silicon (Si) uptake. Studies have shown that knocking out OsNIP2;1 reduces both Si and As uptake, thereby limiting their translocation to aerial plant parts. However, Si is an essential element in plants, playing a crucial role in mitigating biotic and abiotic stresses. Therefore, a complete knockout of OsNIP2;1 is not a viable solution. Instead, precise modification of OsNIP2;1 is required to selectively block As uptake while preserving Si transport. The proposed study aims to engineer the OsNIP2;1 gene using CRISPR-Cas9 genome editing, ensuring reduced As accumulation in rice without impairing Si uptake, yield, or nutritional quality. This approach will contribute to enhanced food safety and sustainability in As-contaminated regions of EIGP while maintaining rice productivity and resilience.

Arsenic, CRISPR-Cas9, gene editing, rice, transporter