Numerous studies have been focusing on breeding tomato plants with enhanced lycopene accumulation, considering its positive effects of fruits on the visual and functional properties. In this study, we used a bidirectional strategy: promoting the biosynthesis of lycopene, while inhibiting the conversion from lycopene to β- and α-carotene. The accumulation of lycopene was promoted by knocking down some genes associated with the carotenoid metabolic pathway. Finally, five genes were selected to be edited in genome by CRISPR/Cas9 system using Agrobacterium tumefaciens-mediated transformation. Our findings indicated that CRISPR/Cas9 is a site-specific genome editing technology that allows highly efficient target mutagenesis in multiple genes of interest. Surprisingly, the lycopene content in tomato fruit subjected to genome editing was successfully increased to about 5.1-fold. The homozygous mutations were stably transmitted to subsequent generations. Taken together, our results suggest that CRISPR/Cas9 system can be used for significantly improving lycopene content in tomato fruit with advantages such as high efficiency, rare off-target mutations, and stable heredity.

SummaryIn recent years, the type II CRISPR system has become a widely used and robust technique to implement site‐directed mutagenesis in a variety of species including model and crop plants. However, few studies manipulated metabolic pathways in plants using the CRISPR system. Here, we introduced the pYLCRISPR/Cas9 system with one or two single‐site guide RNAs to target the tomato phytoene desaturase gene. An obvious albino phenotype was observed in T0 regenerated plants, and more than 61% of the desired target sites were edited. Furthermore, we manipulated the γ‐aminobutyric acid (GABA) shunt in tomatoes using a multiplex pYLCRISPR/Cas9 system that targeted five key genes. Fifty‐three genome‐edited plants were obtained following single plant transformation, and these samples represented single to quadruple mutants. The GABA accumulation in both the leaves and fruits of genomically edited lines was significantly enhanced, and the GABA content in the leaves of quadruple mutants was 19‐fold higher than that in wild‐type plants. Our data demonstrate that the multiplex CRISPR/Cas9 system can be exploited to precisely edit tomato genomic sequences and effectively create multisite knockout mutations, which could shed new light on plant metabolic engineering regulations.

Objective: We investigated the contribution of several cytokines in the pathogenesis of first-onset neuromyelitis optica spectrum disorder (NMOSD) and determined the differences between aquaporin 4 immunoglobulin G (AQP4-IgG)-positive and AQP4-IgG-negative subtypes. Methods: We enrolled 18 NMOSD (10 AQP4-IgG-positive and 8 AQP4-IgG-negative) and 8 multiple sclerosis (MS) patients, whose serum and cerebrospinal fluid (CSF) samples were collected during the acute phase of the first onset before immunotherapy. Fifteen patients with other noninflammatory neurological diseases (OND) were also included. The serum and CSF levels of interleukin (IL)-6, IL-10, IL-17, IL-21, IL-23, transforming growth factor (TGF)-β1 and the CSF levels of 3 biomarkers of axonal loss and astrocytic damage were measured using the human cytokine multiplex assay or ELISA. Results: Serum levels of IL-10 and TGF-β1 and CSF levels of IL-6, IL-10, and TGF-β1 were significantly increased in first-onset NMOSD compared to in OND patients. In a subgroup analysis, the CSF levels of IL-6, neurofilament light protein (NFL), S100B, and glial fibrillary acidic protein (GFAP) were significantly more elevated in the AQP4-IgG-positive patients than in the AQP4-IgG-negative NMOSD patients. Correlations were found between the CSF cytokines and tissue damage biomarkers and the clinical findings in NMOSD patients. Notably, the CSF IL-6 level had the strongest correlation with the tissue damage biomarkers and it also correlated with CSF white blood cell (WBC) count. Conclusions: IL-6 plays a role in the pathogenetic process of NMOSD, especially in the AQP4-IgG-positive subtype. Distinct pathogenesis exists between AQP4-IgG-positive and AQP4-IgG-negative NMOSD in the initial phase of the disease.

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Astrocytic impairment is a pathologic feature of neuromyelitis optica spectrum disorder (NMOSD). S100B and glial fibrillary acidic protein (GFAP) are the two most commonly used astrocytic markers. The aim of this study was to evaluate whether CSF-S100B could serve as a marker of NMOSD. We enrolled 49 NMOSD patients [25 aquaporin-4 antibody (AQP4-Ab)–positive, 8 myelin-oligodendrocyte glycoprotein antibody (MOG-Ab)-positive, and 16 seronegative patients], 12 multiple sclerosis (MS) patients, and 15 other noninflammatory neurological diseases (OND) patients. The CSF levels of S100B and GFAP were measured by ELISA. Both CSF-S100B and GFAP levels significantly discriminated NMOSD from MS [area under curve (AUC) = 0.839 and 0.850, respectively] and OND (AUC = 0.839 and 0.850, respectively). The CSF-S100B levels differentiated AQP4-Ab–positive NMOSD from MOG-Ab–positive NMOSD with higher accuracy than the CSF-GFAP levels (AUC=0.865 and 0.772, respectively). The CSF-S100B levels also significantly discriminated MOG-Ab–positive patients from seronegative patients (AUC = 0.848). Both CSF-S100B and GFAP levels were correlated with the Expanded Disability Status Scale (EDSS) during remission. Only the CSF-S100B levels were correlated with the CSF WBC count and the EDSS during attack. The levels of CSF-S100B seemed to have a longer lasting time than the levels of CSF-GFAP, which may benefit patients who present late. As a result, CSF-S100B might be a potential candidate biomarker for NMOSD in discriminating, evaluating severity, and predicting disability.