Application of Genome Editing in Tomato Breeding: Mechanisms, Advances, and Prospects

Abstract

Plants regularly face the changing climatic conditions that cause biotic and abiotic stress responses. The abiotic stresses are the primary constraints affecting crop yield and nutritional quality in many crop plants. The advances in genome sequencing and high-throughput approaches have enabled the researchers to use genome editing tools for the functional characterization of many genes useful for crop improvement. The present review focuses on the genome editing tools for improving many traits such as disease resistance, abiotic stress tolerance, yield, quality, and nutritional aspects of tomato. Many candidate genes conferring tolerance to abiotic stresses such as heat, cold, drought, and salinity stress have been successfully manipulated by gene modification and editing techniques such as RNA interference, insertional mutagenesis, and clustered regularly interspaced short palindromic repeat (CRISPR/Cas9). In this regard, the genome editing tools such as CRISPR/Cas9, which is a fast and efficient technology that can be exploited to explore the genetic resources for the improvement of tomato and other crop plants in terms of stress tolerance and nutritional quality. The review presents examples of gene editing responsible for conferring both biotic and abiotic stresses in tomato simultaneously. The literature on using this powerful technology to improve fruit quality, yield, and nutritional aspects in tomato is highlighted. Finally, the prospects and challenges of genome editing, public and political acceptance in tomato are discussed.

Genetic and Molecular Mechanisms Conferring Heat Stress Tolerance in Tomato Plants

“…Genome editing has already been used to improve stress resistance in tomatoes. For example, the mitogen-activated protein kinase (mapK) 3 gene, slmapK3 gene, branched-amino acid (ALS1), cytidine base editor (CBE) genes, and LATERAL ORGAN BOUNDARIES DOMAIN-LBD TF gene-SlLBD40 increased resistance to HS, sulfonylurea herbicide chlorsulfuron, and drought, respectively (Ayenan et al, 2019;Yu et al, 2019;Salava et al, 2021;Xia et al, 2021). Both the achievements of genome editing technology with regard to tomatoes and the identification of key genes, such as HsfA2, HsfB1, JA/COI1, SlAGL6, and SlIAA9, are related to the thermotolerant acquires mechanism in tomatoes, positively contribute to the breeding of heat-tolerant tomato.…”

Molecular Breeding Strategy and Challenges Towards Improvement of Downy Mildew Resistance in Cauliflower (Brassica oleracea var. botrytis L.)

“…In recent years, the application of different gene-editing techniques in several horticultural crops has substantially increased to enhance crop production and quality ( Xu et al, 2019 ). Among the horticultural crops, most of the gene-editing studies (72%) have been conducted in vegetables ( Xu et al, 2019 ) and among the vegetables, tomato has gained more attention for gene-editing studies ( Wang et al, 2019 ; Salava et al, 2021 ) which have been performed most frequently up to 42% ( Xu et al, 2019 ). Recently, the mutation of a single gene, DMR6 (downy mildew resistance 6) in Arabidopsis generated plants with increased salicylic acid levels and showed resistance to the bacterium Pseudomonas syringae and oomycete Phytophthora capsici ( Zeilmaker et al, 2015 ).…”

Defense Strategies: The Role of Transcription Factors in Tomato–Pathogen Interaction

“…To compensate for the limited genetic diversity within the cultivated S. lycopersicum species, the genetic engineering that involves the transfer of desired genes broadens the chances for crop improvement. Several genome editing approaches for breeding goals applications were already implemented for tomato resistance to various biotic and abiotic stresses and for traits improvement (see review in [ 24 ]).…”