Abstract: The large-fruited cultivated tomato resource“T048”was used as the material for targeted editing of the tomato stay-green gene SlSGR1 using CRISPR/Cas9 technology. Sequence analysis of the target sites of 19 positive transgenic plants revealed that a total of ten plants had editing events，with an editing efficiency of 52.6%. The types of editing events involved deletions，insertions and substitutions of bases，most of which occurred 3–4 bp upstream of the PAM sequence. A total of 565 bp of sequence inversion between the two editing sites was also detected. Phenotypic analysis revealed that the homozygous edited plants in the T1 generation showed slower senescence of the leaves and rusty red color fruits，with significantly higher content of lycopene，chlorophyll and β-carotenoid，compared with unedited fruits. Analysis of the key genes for carotenoid synthesis revealed that the expression of the SGR1 in the fruit of the homozygous edited plants was significantly lower than that of the unedited plants，whereas the expression of the PSY1 was significantly higher than that of the unedited one. This study demonstrated that targeted editing of the SlSGR1 gene by CRISPR/Cas9 technology can effectively enhance the content of carotenoids such as lycopene and β-carotene in tomato fruits，and thus provide new germplasm for tomato nutritional quality breeding.

Key words: tomato, geno editing, lycopene, carotenoid, SlSGR1