Recent Developments in CRISPR/Cas9 Genome-Editing Technology Related to Plant Disease Resistance and Abiotic Stress Tolerance

SIMPLE SUMMARY: Pests and diseases, along with environmental factors, significantly contribute to yield losses in crop production. Considering the detrimental impact of pesticides on both the economy and the environment, it is crucial to urgently develop methods that can prevent such damage. Additionally, it is imperative to address challenges posed by the growing world population, climate change, and the emergence of new pathogens. In this century, one of the most important advancements in terms of crop improvement lies in faster and more effective genome editing than is possible via traditional plant breeding, resulting in the production of transgene-free plant lines. The CRISPR/Cas9 genome-editing technique has emerged as the most widely used tool for creating plants with desirable traits, such as disease resistance and tolerance to abiotic stresses. These technologies enable the cultivation of crop plants capable of adapting to these new conditions, offering novel opportunities and solutions. ABSTRACT: The revolutionary CRISPR/Cas9 genome-editing technology has emerged as a powerful tool for plant improvement, offering unprecedented precision and efficiency in making targeted gene modifications. This powerful and practical approach to genome editing offers tremendous opportunities for crop improvement, surpassing the capabilities of conventional breeding techniques. This article provides an overview of recent advancements and challenges associated with the application of CRISPR/Cas9 in plant improvement. The potential of CRISPR/Cas9 in terms of developing crops with enhanced resistance to biotic and abiotic stresses is highlighted, with examples of genes edited to confer disease resistance, drought tolerance, salt tolerance, and cold tolerance. Here, we also discuss the importance of off-target effects and the efforts made to mitigate them, including the use of shorter single-guide RNAs and dual Cas9 nickases. Furthermore, alternative delivery methods, such as protein- and RNA-based approaches, are explored, and they could potentially avoid the integration of foreign DNA into the plant genome, thus alleviating concerns related to genetically modified organisms (GMOs). We emphasize the significance of CRISPR/Cas9 in accelerating crop breeding processes, reducing editing time and costs, and enabling the introduction of desired traits at the nucleotide level. As the field of genome editing continues to evolve, it is anticipated that CRISPR/Cas9 will remain a prominent tool for crop improvement, disease resistance, and adaptation to challenging environmental conditions.