基于课题组前期研究发现VIGS沉默NAC4与NAC9的番茄果实表现出相反的果实软化趋势，本项目首先采用GUS体内鉴定启动子的方法，构建NAC4和NAC9 promoter deletion 载体， 通过GUS staining 和GUS含量检测， 确定SNAC4和9的调控成熟的启动子元件；在此基础上利用先进的基因编辑技术CRISPR技术，获得CRISPR/Cas9 NAC4和NAC9 单基因和多基因沉默的转基因SNAC番茄（包括启动子区域），在基因和蛋白水平上系统分析色素代谢、胞壁代谢和激素水平变化规律；明确NAC4和NAC9 的调控番茄成熟差异模式；以及与激素乙烯、ABA、JA、SA关系。项目的研究成果有助于揭示番茄果实NAC转录因子家族不同基因在成熟衰老中的调控机制，深入探索明确NAC调控果实成熟衰老机制，同时丰富CRISPER基因编辑技术在采后研究领域的应用理论。

Based on the previous study of the research group, we found that VIGS-silenced NAC4 and NAC9 tomato fruits showed opposite fruit softening tendency. This project will use the GUS in vivo method to identify promoters, construct NAC4 and NAC9 promoter deletion fragments, and detect them by GUS staining and GUS contents. The ripening regulatory promoter elements of SNAC4 and 9 will be identified; on this basis, CRISPR/Cas9 NAC4 and NAC9 single genes and polygene-silenced transgenic SNAC tomato (including promoter regions) were obtained using advanced gene editing technology- CRISPR technology. Genetic and protein levels will be systematically analyzed for changes in pigment metabolism, cell wall metabolism, and hormone levels; the patterns of NAC4 and NAC9 regulation of tomato ripening; and the relationships with hormones ethylene, ABA, JA, and SA. The research results of the project will help to reveal the regulatory mechanisms of different genes in the tomato NAC family of transcription factors during ripening and senescence, explore in depth the clear mechanism of NAC regulating fruit maturation and senescence, and enrich the theory of application of the CRISPER gene editing technology in postharvest research.