CRISPR/Cas-Mediated Genome Editing for Developing Herbicide Tolerant Rice: A Step-by-Step Protocol.

Weed management in rice cultivation has predominantly relied on acetolactate synthase (ALS) and acetyl-CoA carboxylase (ACCase) inhibiting herbicides, particularly against Echinochloa spp. (watergrass). However, these herbicides carry a high risk of resistance evolution, as evidenced by the numerous resistant biotypes reported worldwide. The emergence of herbicide resistance necessitates innovative and sustainable weed control strategies. Genome editing, particularly through the CRISPR/Cas system, provides a precise and efficient platform for introducing targeted genetic modifications to develop herbicide-tolerant (HT) rice cultivars. In this protocol, we present a step-by-step approach for generating bispyribac sodium-tolerant rice using the CRISPR/Cas-mediated editing of the ALS gene. The method encompasses guide RNA design, vector construction, transformation, selection of edited plants, and molecular confirmation of targeted mutations. This approach offers a robust framework for producing HT rice lines, potentially reducing reliance on conventional herbicide regimes and mitigating the risk of resistance development in weed populations.