Genome editing for herbicide tolerance in crop plants

Herbicides are widely used to eradicate or control undesirable weeds. However, the major problems associated with this are the capability of weeds to develop resistance against herbicides, toxic effects on non-target organisms, and residue perseverance within the soil and its seepage into groundwater. Cultivating herbicide-tolerant (HT) crops provides farmers with valuable options for effective weed control, ultimately leading to increased crop yields. Therefore, introducing HT crops is one of the most resourceful strategies for controlling the proliferation of weeds via genetic engineering. In recent decades, traditional breeding, combined with transgenic methods and mutagenesis, has been pivotal in driving the progress of herbicide-resistant (HR) crops. The current, most suitable alternative to conventional genetic engineering approaches for developing HT plants is the creation of transgenic varieties through targeted genome editing. Presently, scientists are finding numerous mutations associated with HT worldwide. This chapter provides an in-depth exploration of various gene editing tools used to make HR crops, with a focus on target-based editing (ABEs and CBEs), CRISPR ribonucleoprotein complexes/Cas9, PLSM, PE, SNPs, NHEJ, BEMGE, and HDR, along with 2 DNA targeting systems (protein based): namely, TALENs, ZFNs-that are utilized for site-directed genome mutagenesis. With these valuable evidential details and relevant information, the creation of new, essential crop varieties, such as rice, soybean, and maize, exhibiting broad-spectrum resistance to several herbicides, can be achieved through successive rounds of genetic engineering.