Flavonoid 3-O-glucosyltransferase (3GT) is a key enzyme in the glucosidation of anthocyanins. To investigate the 3GT gene in rhododendron, we cloned an open reading frame (ORF) of 3GT gene (named Rh3GT) from Rhododendron hybridum Hort (Red cultivar) and then characterized this gene and the deduced protein in terms of the biochemical characteristics, expression level, and enzymatic function. The results showed that Rh3GT had a full length of 993 bp and encoded 330 amino acid residues. The deduced protein was hydrophilic, stable, weak acid, belonging to the glycosyltransferase family (GT-B type), with glutamine (Q) at position 44 in the PSPG box. The phylogenetic analysis showed that Rh3GT was most closely related to Vc3GT from Vaccinium corymbosum and Vm3GT from Vaccinium myrtillus. Rh3GT was expressed in the stems, leaves, and flowers and almost not expressed in the roots, with the highest expression level in petals during full blooming stage. Introduction of pCAMBIAL1302-Rh3GT into petals significantly up-regulated the expression level of Rh3GT and increased the total anthocyanin accumulation. Rh3GT was successfully expressed in Escherichia coli BL21 in the form of inclusion bodies with a size of about 36 kDa. The results of HPLC showed that the recombinant Rh3GT after denaturation, purification, and dilution could catalyze the synthesis of cyanidin and UDP-glucose to synthesize cyanidin 3-O-glucoside, indicating that the expressed protein had 3GT activity. This study provides basic data for further studying the molecular regulation mechanism of anthocyanin biosynthesis and theoretical support for molecular breeding of rhododendron.
Rhododendron/classification* ; Glucosyltransferases/metabolism* ; Cloning, Molecular ; Escherichia coli/metabolism* ; Recombinant Proteins/biosynthesis* ; Anthocyanins/biosynthesis* ; Phylogeny ; Plant Proteins/metabolism* ; Amino Acid Sequence

The instability of secondary metabolite production is a ubiquitous problem in plant cell culture. In order to understand the instability in plant cell culture, we investigated anthocyanin accumulation in suspension cultures of Vitis vinifera, as a model system, in our laboratory. Not only the anthocyanin contents but also its composition exhibited instability along with the long-term subculture. New methods were developed to indicate the instability of plant cell culture. Both the definition of instability coefficient (delta) and the application of factor scores were the first time in this field. To examine the effects of culture conditions on instability of anthocyanin biosynthesis, different subculture cycles and inoculum sizes had been investigated. Subculture cycle and inoculum size were both environmental cues driving the instability. Compared with subculture cycle, inoculum size was more effective in working on the instability of anthocyanin accumulation. Among all the conditions investigated in our study, (6.5 d, 2.00 g), (7 d, 2.00 g), (7.5 d, 2.00 g), (7 d, 1.60 g) and (7 d, 2.40 g), the condition of 7 d-subculture cycle together with 1.60 g-inoculum size was the best one to keep the stable production of anthocyanins.
Anthocyanins ; biosynthesis ; chemistry ; Culture Techniques ; methods ; Time Factors ; Vitis ; growth & development ; metabolism

The commercial application of plant cell cultures is often hindered by the instability of secondary metabolite biosynthesis, where the metabolite yield fluctuates and decline dramatically over subcultures. This study proposed that such instability is due to the fluctuations of culture variables. To validate this hypothesis, the effects of the fluctuations of two culture variables (subculture cycle and inoculum size) on the biomass, anthocyanin biosynthesig, intracellular carbon, nitrogen and phosphate during continuous 10 subculture cycles were investigated. The subculture cycle was fluctuated for 12h in a 7 day cycle (6.5, 7 and 7.5 d), and the inoculum size was fluctuated by 20% on basis of 2.00 g (1.60, 2.00 and 2.40 g). It was found that all the measured culture parameters fluctuated over the 10 subculture cycles. The fluctuation in terms of inoculum sizes had a greater effect on the stability of anthocyanin biosynthesis in suspension cultures of V. vinifera. Among all the subculture conditions investigated, 7d-subculture cycle and 1.60 g-inoculum size was the best one to hold the relatively stable anthocyanin production. The anthocyanin yield presented a negative correlation with intracellular sucrose content or intracellular total phosphate content.
Anthocyanins ; biosynthesis ; Carbohydrate Metabolism ; Cell Culture Techniques ; methods ; Intracellular Space ; metabolism ; Phosphates ; metabolism ; Plant Proteins ; metabolism ; Suspensions ; Vitis ; cytology ; growth & development ; metabolism

The instability of secondary metabolite production is a ubiquitous problem in plant cell culture. To understand the instability, the investigation of anthocyanin accumulation in suspension cultures of Vitis vinifera, as a model system, has been initiated in our laboratory. Suspension culture of a relatively homogeneous cell line E of V. vinifera, was established by long-term cell line selection by anthocyanin content differentiation. The aggregate size of E was smaller than that of other cell lines obtained by routine screening method. The variation coefficients of anthocyanin content in suspension cultures of E were 8.7% in long-term subcultures and 5% in repeated flasks, respectively. The effects of elicitor, precursor feeding and light irridiation on biomass and anthocyanin accumulation in suspension cultures of E had been investigated and the results showed that all the variation coefficients were lower than 12% and this indicated the importance of homogeneity on stable production in plant cell culture. With the combination treatment of 30micromol/L phenylalanine and 218micromol/L methyl jasmonate in the dark in suspension cultures of E, the anthocyanin content and production in suspension culture of E was 5.89-fold and 4.30-fold of the controls, respectively, and all the variation coefficients of biomass and anthocyanin accumulation were lower than those of the controls in 5 successive subcultures.
Anthocyanins ; biosynthesis ; Biomass ; Cell Proliferation ; Light ; Suspensions ; Vitis ; cytology ; metabolism

Camptothecin is a strong anti-tumor compound isolated from Camptotheca acuminata. One of the most important way for the production of Camptothecin is by cell cultures of Camptotheca acuminata. The effect of Cu2+ on camptothecin accumulation in Camptotheca acuminata cell line was described in this paper. The results showed that the optimum CuCl2 concentration in B5 medium was 0.008 mg/mL, which increased camptothecin production for 30 times compare to the control while has no inhibitive effects on cell growth, at the same time, the peroxidase activity was increased and the anthocyanidin accumulation was inhibited. The promotive effects of Cu2+ on camptothecin accumulation in light was higher than that in dark.
Anthocyanins ; biosynthesis ; Antineoplastic Agents, Phytogenic ; biosynthesis ; Camptotheca ; growth & development ; metabolism ; Camptothecin ; biosynthesis ; Copper ; pharmacology ; Light

The low-production is a ubiquitous problem and has prevented the commercialization of secondary metabolite production in plant cell culture. In order to examine the effective approaches to improvement of secondary metabolite production in plant cell culture, the investigation of anthocyanins accumulation in suspension cultures of Vitis vinifera, as a model system, had been initiated in our laboratory. In this present research, various elicitors and the precursor of phenylalanine were used in combination to enhance the anthocyanins production in suspension cultures of Vitis vinifera. And an integrated process with the combination of elicitation, precursor feeding and light irradiation was reported for rational bioprocess design. Among the combination treatment of phenylalanine feeding and several elicitors (methyl-beta-cyclodextrin, dextran T-40, methyl jasmonate, extracts of Aspergillus niger and Fusarium orthoceras), the combination with methyl jasmonate gave the highest anthocyanins production in suspension cultures of Vitis vinifera. When compared to the controls, the anthocyanins content (CV/g, FCW) and production (CV/L) increased by 2.7-fold and 3.4-fold, respectively. The optimum time for the addition of phenylalanine and methyl jasmonate was 4 days after inoculation. Two cell lines with different anthocyanins-producing capacity responded differently to the optimum combination treatment of 30 micromol/L phenylalanine feeding, 218 micromol/L methyl jasmonate elicitation and 3000 to approximately 4000 1x light illumination. The high-and low-anthocyanins-producing cell lines of VV05 and VV06 produced the maximum of 2975 and 4090 CV/L of anthocyanins that were 2.5- and 5.2-fold of the controls, respectively.
Acetates ; pharmacology ; Anthocyanins ; biosynthesis ; Cell Culture Techniques ; methods ; Cells, Cultured ; Culture Media ; Cyclopentanes ; pharmacology ; Light ; Oxylipins ; pharmacology ; Phenylalanine ; pharmacology ; Vitis ; cytology ; metabolism