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Vitamin C (Vitamin C, Vc), also known as ascorbic acid (ascorbic acid, AsA), as an antioxidant, not only broad participation of oxidative stress response in animals and plants, but also as a coenzyme and an electron acceptor, and light on plant growth and and has an important role in the process of biological functions. Studies have shown that vitamin C synthesis in plants with L-galactose pathway, the uronic acid pathway, and inositol pathway gulonic pathway and several other synthetic pathway, wherein the L-galactose pathway of vitamin C in plants most synthetic pathway. In dicotyledonous model plant Arabidopsis thaliana, L-galactose pathway genes have been cloned all, and carried out functional studies. Studies have shown that L-galactose pathway catalyzed 1 - generates GDP-mannose phosphate mannose GDP-mannose pyrophosphorylase (GMPase) L-galactose pathway is a key enzyme. Point in the gene encoding the enzyme mutant vtc1-1, the content of vitamin C decreased, vitamin C content of only about 30% of wild type. But the important food crops of rice, the synthesis of vitamin C is little research on the major route L-galactose pathway enzymes and genes critical function is not clear. Early laboratory and regulation of protein found in Arabidopsis VTC1 protein stability in CSN5B COP9 complex subunit interactions, CSN5B can be adjusted by regulating the stability VTC1 synthesis of vitamin C, the impact of oxidative stress response in Arabidopsis. By comparing protein sequences and found that there are three coding VTC1 rice protein homolog (OsVTC1-1, OsVTC1-3, O sVTC1-8). OsVTC1-1, OsVTC1-3 and OsVTC1-8 encodes a protein with homology VTC1 were 87.26%, 87.53%, 87.26%; study the characteristics of these three genes encoding the enzyme activity and synthesis of vitamin C The regulatory role. Experimental results show that the OsVTC1-1, OsVTC1-3 and OsVTC1 * 8 in, OsVTC1-1 play a major role in the synthesis of vitamin C rice major regulatory genes. This experiment CSN5B homology comparison, encoding a protein found in rice CSN5B a high similarity with genes OsJAB1, the similarity is 72.38%, and their protein homology 77.56% Based on this yeast two hybrid experiments and preliminary analysis OsJAB1 OsVTC1-1, OsVTC1-3 and OsVTC1-8 is an interaction, and the interaction between them are in the area of ??the N-terminal protein. By building OsJAB1 prokaryotic expression vector, further validation via pull-down OsJAB1 with OsVTC1 interactions. Studies show that there is interaction OsJAB1 with OsVTC1. Real-time PCR detection of the use of rice (Nipponbare) in OsJAB1 expression properties. Study found OsJAB1 with OsVTC1-1 expression and CSN5B and VTC1 in Arabidopsis characteristics are very similar, indicating that OsJAB1 with OsVTC1-1 may have CSN5B and VTC1 similar regulatory functions. Also in order to study the function in rice OsJAB1 build OsJAB1 overexpression and interference vectors, creating OsJAB1 overexpression transgenic rice materials and interference. Transgenic rice to detect vitamin C content to verify OsJAB1 right OsVTC1 role in regulating showed that the vitamin C content is different with the wild type, indicating that regulation may exist between them. Together, the above results show, OsJAB1 and OsVTCl-1, OsVTC1-3, OsVTC1-8 are present interaction, but OsJAB1 OsVTCl-1 with the strongest binding ability. With OsVTCl-1 vitamin C synthesis in rice play a major role correspondence, DsJAB1 with OsVTC1-1 expression correlation, suggesting OsJAB1 could regulate OsVTC1-1 regulating the stability of rice in the biosynthesis of vitamin C, vitamin C synthesis play an important role.
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