Gene editing tool kit in millets: present status and future directions

Millets, the sixth most-grown group of crops in the drylands, support the livelihood of many small-holder farmers in the region. Being one of the most nutritious groups of crops, their production has been increasing since the last decade to meet the demands of the world’s ever-increasing population. Since its discovery, CRISPR/Cas-mediated gene editing technology has revolutionized trait improvement in numerous crops by enabling targeted insertions and deletions at specific gene sequences. With advancements like base editing and prime editing, which offer precise modifications at the nucleotide level, this technology holds great promise for enhancing millets by targeting genes responsible for key traits. The updated sequence information in the public domain makes it possible to modify certain genic regions using the CRISPR/Cas-mediated gene editing technology to develop millet crops with improved agronomical properties. The review explores each component of the editing toolbox in millets, including the gRNA designing tools, types of Cas nucleases, and promoters to be considered for enhanced and efficient gene editing in millets. We have discussed fundamental information available to successfully employ CRISPR/Cas-mediated gene editing in millets, such as the availability of genomic information and plant transformation methods. Finally, we have highlighted the limitations of employing this novel technology in millet crops by providing future directions and immediate candidate genes that could be targeted to improve various traits in millet crops.