The Application of Genome Editing Technologies in Soybean (Glycine max L.) for Abiotic Stress Tolerance

Soybean (Glycine max L.) is one of the five major cultivated crops that are important in the world, and it is also a major source of oil and protein for humans and livestock. But its seed yield is relatively low compared with rice, wheat, and other food crops. Soybean is subject to many biotic and abiotic stresses throughout its whole growth stages, and different growth habits have an impact on yield. Based on the rapid development of whole-genome sequencing and genome editing technology, precise improvement of soybean cultivars gains an unprecedented possibility. The clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) system is widely utilized for genome editing following zinc-finger nucleases (ZFNs) and transcription activator-like effector nucleases (TALENs). This system provides scientists with the capability to efficiently, precisely, and simply modify target genes. In this chapter, we provide a comprehensive review of three primary genome editing techniques (ZFNs, TALENs, and CRISPR/Cas9) in the application of soybean research. Numerous scholarly works have thoroughly recorded CRISPR/Cas9’s ability to alter soybean genes responsible for controlling agronomic and quality traits. However, limited attention has been given to the editing of genes associated with abiotic stress. Nonetheless, a substantial number of soybean genes have been meticulously analyzed and examined in this regard. Due to the pronounced impact of abiotic stress on soybean seed yield, this chapter primarily consolidated and examined the editing occurrences of abiotic stress-associated genes utilizing CRISPR/Cas9 technology. Specifically, it addressed drought stress, salt stress, and heavy metal stress. It appraised the potential of novel genome editing technologies such as CRISPR/Cas9-based base editor, prime editor, and dual-sgRNA/Cas9 system in relation to soybean research. This updated chapter was intended to furnish comprehensive theoretical guidance for the investigation of genetic mechanisms underlying abiotic stress tolerance and the corresponding breeding efforts in soybeans.