CRISPR/Cas9-mediated editing of OsLsi1 and OsLsi2 genes reduce arsenic uptake and accumulation in Indica rice (Oryza sativa L.).

Abstract

Arsenic (As) contamination in rice poses a serious health concern, particularly for communities that depend on rice as a primary dietary staple. Developing rice varieties with consistently low As content has proven difficult using traditional breeding methods, highlighting the need for novel approaches. Targeting genes responsible for As accumulation in rice could be a key strategy to address this issue. In this study, we explored whether editing the silica transporters genes OsLsi1 and OsLsi2, responsible for co-transporting As in rice, could reduce As accumulation while maintaining grain yield. Using CRISPR/Cas9 technology, we targeted the promoter and N-terminal coding regions of these genes, to produce homozygous transgene-free edited lines. Expression analysis revealed that the mutations led to a 2-3.5-fold and a 5-70-fold decrease in the expression of OsLsi1 and OsLsi2 transcripts, respectively, in rice roots. Both mutant and wild-type lines were exposed to silicic acid (5 mM) and sodium arsenite (10 µM) in short-term hydroponic experiments to assess the uptake of arsenic and silicon (Si) in their roots and shoots. The results showed a significant reduction in As (21-32% in roots and 62-74% in shoots) and Si (33-80% in roots and 35-78% in shoots) concentrations, compared to wild-type plants. Notably, the mutant line (2E-24), created by editing the OsLsi2 coding region, did not result in any yield loss under controlled pot conditions. The results indicate that editing OsLsi2 may offer a promising approach to lower arsenic accumulation in rice while maintaining grain productivity.

Supplementary information: The online version contains supplementary material available at 10.1007/s12298-025-01702-2.