Fruit-specific RNAi-mediated Restraining Expression of Lcy Gene to Enhance Lycopene Content in Tomatoes

Tomato (Lycopersicon esculentum Mill.) fruits are the principal dietary source of Lycopene, which is a kind of carotenoid, and is highly beneficial in preventing some diseases such as cancer and heart disease. Expression suppression of lycopene cyclase (Lcy) gene, the main gene regulating the transformation of the lycopene, is a convenient and effective way to enhance the content of lycopene. The primers were designed according to the gene sequence (U46919) and (X86452) in GenBank. The fruit-specific promoter of phytoene desaturase gene (Pds) and the DNA segment of the Lcy gene were isolated from the genomic DNA of tomatoes. The 3′ end of Lcy DNA segment was connected together by an intron to inform the RNA interferential segment which was then inserted in the expression vector with the Pds promoter to inform the fruit-specific expression vector. The vector was transformed into the tomatoes through Agrobacterium tumefaciens. Five transformants were obtained, and the PCR proved that the transgene was integrated into the tomato genome. The lycopene in the transgenic tomato fruits was increased significantly through contents analysis of lycopene. These results show that manipulation of biosynthesized enzyme of carotenoid pathway by RNAi can improve the content of lycopene of plant-derived products.