[Improvement of Crops Using the CRISPR/Cas System: New Target Genes]

The success of genome editing of crops using the CRISPR/Cas system largely depends on the correct choice of target genes, for which directed changes will increase yield and improve the quality of plant raw materials and resistance to biotic and abiotic stress factors. This work systematizes and catalogs data on target genes used to improve cultivated plants. The latest systematic review examined articles indexed in the Scopus database and published before August 17, 2019. Our work covers the period from August 18, 2019 to March 15, 2022. A search according to the given algorithm allowed us to identify 2090 articles, among which only 685 contain the results of gene editing of 28 species of cultivated plants (the search was carried out for 56 crops). A significant part of these papers considered either editing of target genes, which was previously carried out in similar works, or studies related to the field of reverse genetics, and only 136 articles contain data on editing of new target genes, whose modification is aimed at improving plant traits important for breeding. In total, 287 target genes of cultivated plants were subjected to editing in order to improve properties significant for breeding over the entire period of the CRISPR/Cas system application. This review presents a detailed analysis of the editing of new target genes. The studies were most often aimed at increasing productivity and disease resistance, as well as improving the properties of plant materials. It was noted whether it was possible to obtain stable transformants at the time of publication and whether editing was applied to non-model cultivars. The range of modified cultivars of a number of crops has been significantly expanded, in particular, for wheat, rice, soybean, tomato, potato, rapeseed, grape, and maize. In the vast majority of cases, editing constructs were delivered using agrobacterium-mediated transformation, less commonly, using biolistics, protoplast transfection, and haploinducers. The desired change in traits was most often achieved by gene knockout. In some cases, knockdown and nucleotide substitutions in the target gene were carried out. To obtain nucleotide substitutions in the genes of cultivated plants, base-editing and prime-editing technologies are increasingly used. The emergence of a convenient CRISPR/Cas editing system has contributed to the development of specific molecular genetics of many crop species.