Applications and Potential of Genome-Editing Systems in Rice Improvement: Current and Future Perspectives

Food crop production and quality are two major attributes that ensure food security. Rice is one of the major sources of food that feeds half of the world’s population. Therefore, to feed about 10 billion people by 2050, there is a need to develop high-yielding grain quality of rice varieties, with greater pace. Although conventional and mutation breeding techniques have played a significant role in the development of desired varieties in the past, due to certain limitations, these techniques cannot fulfill the high demands for food in the present era. However, rice production and grain quality can be improved by employing new breeding techniques, such as genome editing tools (GETs), with high efficiency. These tools, including clustered, regularly interspaced short palindromic repeats (CRISPR) systems, have revolutionized rice breeding. The protocol of CRISPR/Cas9 systems technology, and its variants, are the most reliable and efficient, and have been established in rice crops. New GETs, such as CRISPR/Cas12, and base editors, have also been applied to rice to improve it. Recombinases and prime editing tools have the potential to make edits more precisely and efficiently. Briefly, in this review, we discuss advancements made in CRISPR systems, base and prime editors, and their applications, to improve rice grain yield, abiotic stress tolerance, grain quality, disease and herbicide resistance, in addition to the regulatory aspects and risks associated with genetically modified rice plants. We also focus on the limitations and future prospects of GETs to improve rice grain quality.