CRISPR/Cas Genome Editing Technologies for Plant Improvement against Biotic and Abiotic Stresses: Advances, Limitations, and Future Perspectives

Abstract

Crossbreeding, mutation breeding, and traditional transgenic breeding take much time to improve desirable characters/traits. CRISPR/Cas-mediated genome editing (GE) is a game-changing tool that can create variation in desired traits, such as biotic and abiotic resistance, increase quality and yield in less time with easy applications, high efficiency, and low cost in producing the targeted edits for rapid improvement of crop plants. Plant pathogens and the severe environment cause considerable crop losses worldwide. GE approaches have emerged and opened new doors for breeding multiple-resistance crop varieties. Here, we have summarized recent advances in CRISPR/Cas-mediated GE for resistance against biotic and abiotic stresses in a crop molecular breeding program that includes the modification and improvement of genes response to biotic stresses induced by fungus, virus, and bacterial pathogens. We also discussed in depth the application of CRISPR/Cas for abiotic stresses (herbicide, drought, heat, and cold) in plants. In addition, we discussed the limitations and future challenges faced by breeders using GE tools for crop improvement and suggested directions for future improvements in GE for agricultural applications, providing novel ideas to create super cultivars with broad resistance to biotic and abiotic stress.

CRISPR/Cas system: A revolutionary tool for crop improvement

“…To overcome this mass crop destruction, CRISPR/Cas system was employed to target coding and non‐coding sequences of gemini‐virus and create viral resistant crop plants. [ 96 ] Apart from genes present in plants, viral genome can also be targeted such as that of bean yellow dwarf virus by CRISPR/Cas system. Plants were infiltrated with T‐DNA encoding CRISPR/Cas reagents and were designed to be complementary to BeYMV genome, having potential to create DSB within the virus, when these breaks were repaired using NHEJ, mutations occurred leading to reduced viral symptoms.…”

Unravelling Abiotic Stress Physiology in Cotton (Gossypium hirsutum L.): Biotechnological Interventions in Mitigating Abiotic Stress

“…Successfully applied for multiple purposes, including validation of sgRNAs for individual genes (GhPDS, GhCLA1, and GhEF1), simultaneous editing of homologous genes, and genomic fragment deletions, this new method showcased its versatility. CRISPR/Cas-induced mutations in stably transformed cotton plants targeting GhCLA1 also resulted in typical albino phenotypes [222][223][224][225][226][227].…”

Maximizing the crop wild relative resources available to plant breeders for crop improvement

“…They are wild plant species relatively closely related to crops, including crop's wild ancestors that retain indirect use value as gene donors for crop improvement and high level of genetic diversity. Although initially the CWR conservation and use focus has been on the most closely related CWR to the crops and the highest value crops, in the longer term it is likely, with the easier application of gene editing (Hartung and Schiemann, 2014;Wang et al, 2022) and by applying speed breeding (Watson et al, 2018), CWR usage will be expanded providing the full breadth of CWR diversity is conserved and available to breeders.…”

“…Some breeders today may still feel working with CWR is not worth the effort. However, the impact of climate change causing breeders to search more regularly for novel traits (McCouch et al, 2013;Dempewolf and Guarino, 2015), the fact that substantial funds are being devoted to the provision of pre-breed lines that already contains beneficial CWR traits for farmer and breeder usage (https://www.croptrust.org/work/projects/ the-bold-project/#c4667; Dempewolf et al, 2017), the increased ease of access to CWR germplasm (Kilian et al, 2021;Eastwood et al, 2022) and the rapid progress in gene editing techniques (Hartung and Schiemann, 2014;Wang et al, 2022) are making linkage drag minimal and means breeder's reluctance to use CWR diversity to maintain food security is less readily justified.…”