Summary of the Frontier Introduction of Preparation of Secondary Metabolites in Plant Cell Culture

Plant cell culture technology is a technology that applies the research results of cell engineering to produce plant biological products at the cellular level.In recent years,the secondary metabolites of plants have attracted more and more attention.The use of plant cell culture technology is a fast and efficient method of producing secondary metabolites.

Plant cell cultures as heterologous bio-factories for secondary metabolite production

Synthetic biology has been developing rapidly in the last decade and is attracting increasing attention from many plant biologists.The production of high-value plant-specific secondary metabolites is,however,limited mostly to microbes.This is potentially problematic because of incorrect post-translational modification of proteins and differences in protein micro-compartmentalization,substrate availability,chaperone availability,product toxicity,and cytochrome p450 reductase enzymes.Unlike other heterologous systems,plant cells may be a promising alternative for the production of high-value metabolites.Several commercial plant suspension cell cultures from different plant species have been used successfully to produce valuable metabolites in a safe,low cost,and environmentally friendly manner.However,few metabolites are currently being biosynthesized using plant platforms,with the exception of the natural pigment anthocyanin.Both Arabidopsis thaliana and Nicotiana tabacum cell cultures can be developed by multiple gene transformations and CRISPR-Cas9 genome editing.Given that the introduction of heterologous biosynthetic pathways into Arabidopsis and N.tabacum is not widely used,the biosynthesis of foreign metabolites is currently limited;however,therein lies great potential.Here,we discuss the exemplary use of plant cell cultures and prospects for using A.thaliana and N.tabacum cell cultures to produce valuable plant-specific metabolites.

MORPHOLOGICAL MODEL FOR RHEOLOGICAL PROPERTIES OF PLANT CELL SUSPENSION CULTURE SYSTEM

This paper puts forward a physical and mathematical model for the rheological properties of a plant cell suspension culture system.The model can explain why the system is pseudoplastic satisfactorily,thus the rheological properties of the system as the effect of the flow behavior index on plant cell concentration are interpreted correctly and the mechanism of the rheological properties of the system is further understood.Therefore the model can be applied in the technological design and optimum conditions of the system and the reformation,evaluation and scale up of reactors.

Biomass accumulation of Panax vietnamensis in cell suspension cultures varies with addition of plant growth regulators and organic additives

Objective: To evaluate the impact of plant growth regulators including kinetin(KN),benzyl adenine and naphthalene acetic acid, yeast extract and casein hydrolyzate on biomass accumulation of Vietnamese ginseng Panax vietnamensis(P. vietnamensis) in cell suspension culture.Methods: Cell suspension cultures were established from friable calluses derived from leaves and petioles of 3-year-old in-vitro P. vietnamensis plants. The cell suspension cultures were grown in Murashige and Skoog basal media supplemented with various concentrations of KN, benzyl adenine, naphthalene acetic acid, and yeast extract and casein hydrolyzate.Results: All tested factors generated an increase in the cell biomass of P. vietnamensis in suspension culture, but the impact of each varies depended on the factor type, concentration, and incubation period. Addition of 2.0 mg/L KN resulted in the largest biomass increase after 24 d,(57.0 ± 0.9) and(3.1 ± 0.1) mg/m L fresh and dry weight, respectively,whereas addition of benzyl adenine or naphthalene acetic acid produced optimum levels of Panax cell biomass at 1.0 and 1.5 mg/L, respectively. Addition of the elicitor yeast extract led to a 1.4–2.4 fold increase in biomass of P. vietnamensis, while addition of casein hydrolyzate enhanced biomass accumulation 1.8–2.6 fold.Conclusions: The addition of each factor causes significant changes in biomass accumulation of P. vietnamensis. The largest biomass accumulation is from cultures grown in MS media containing 2.0 mg/L KN for 24 d. The outcome of the present study provides new insights into the optimal suspension culture conditions for studies on the in vitro cell biomass production of P. vietnamensis.

Contributions of Chinese Botanists to Plant Tissue Culture in the 20th entury

This paper looks back to the development of plant tissue culture in China in the last century. Since 1934, tissue culture studies in China has kept up with the international development in the fields. Progress has been made by Chinese in nearly every branches of tissue culture, including in vitro organogenesis, shoot tip culture, anther culture, ovary culture, endosperm culture, protoplast culture as well as mass cell culture. On the basis of reviewing the articles written by Chinese on plant tissue culture, the internationally recognized contributions are specially mentioned. The applications of plant tissue culture to agriculture and industry in China are also introduced.

Effects of medium nutrition on cell growth and isocamptothecin A and B production by suspension cell culture of Camptotheca acuminata

The effects of initial sucrose concentration, nitrate to ammonium ratio, total N concentration and phosphate concentration in medium on cell growth and isocamptothecin A and B synthesis by suspension call culture of Camptotheca acuminata were investigated in 250 mL shake flasks. 30 g L^-1 sucrose concentration was beneficial to secondary metabolites synthesis. The cell growth and metabolites synthesis were also affected by the ratio of NO3^-/NH4^＋ , and nitrate was tavourable for cell growth. The maximum dry weight was achieved when nitrate was used as the sole N souree. The effect of total initial N on the cell cultures was also investigated with NO3^-/NH4^＋ ratio of 1 ： 2. The final dry cell weight was similar throughout culture period and 50 mM initial N was favourable for secondary metabolite synthesis. 50 mM initial phosphate concentration facilitated both cell growth and secondary metabolites synthesis.

Dynamic Effects of Cerium on Syntheses of Soluble Protein and Taxol in Suspension Culture of Taxus Chinensis Var. Mairei Cells

The dynamic effects of Ce4+ on the syntheses of soluble protein and taxol in suspension cultures of Taxus chinensis var. mairei cells were studied. The phenomena of 'partition' and 'bifurcation' were observed in studying the dynamic effect of Ce4+ on soluble protein synthesis and cell activity. That is, Ce4+ of low concentration improves the soluble protein synthetic strength and cell activity, while Ce4+ of high concentration is harmful to protein synthesis and cell activity. In addition, Ce4+ of appropriate concentration enhances taxol synthesis.

Production of paeoniflorin and albiflorin by callus tissue culture of Paeonia lactiflora Pall

In order to facilitate the preparation of paeoniflorin(PF)and albiflorin(AF),two chief bioactive constituents in Paeonia lactiflora Pall(PL),induction and culture of callus from PL were studied.With a modified woody plant medium supplemented with 0.5 mg·L-16-benzylaminopurine,1.0 mg·L-1naphthylacetic acid,0.1 mg·L-1thidiazuron and 30 g·L-1sucrose,callus was induced from four kinds of explants:leaf,stems,petiole,and root.The potency to form callus varies between different explants and leaf explants exhibits the highest capacity(100%).On the other hand,root-derived callus(R-callus)produces the highest level of total amount of PF and AF,31.8 mg·g-1dry mass,which is higher than the corresponding level in the root of field cultivated PL.Furthermore,the time needed is only 40 days,remarkably shorter than the cultivation time of PL,about 4–5 years.Higher accumulation levels of PF and AF with shorter production time indicate that callus culture of PL is a promising powerful tool for production of PF and AF in the future.

Research Progress on Production of Podophyllotoxin from Sinopodophyllum hexandrum

Podophyllotoxin is isolated mainly from the rhizomes of Podophyllum plants, and serves as the main precursor for synthesis of anticancer drugs, such as VP-16 and VM-26. VP-16 and VM-26 are used for curing lung cancer, testicular cancer, neuroblastoma, hepatoma and other tumors. However, these plants are all near-extinction species due to over-collection and their own biological characteristics. The chemical synthesis of podophyllotoxin is so complicated that its price is unbelievably high. This paper discusses the current status of the biosynthetic pathway of podophyllotoxin and that of the podophyllotoxin production using several biotechnological approaches such as plant organ cultures, plant cell cultures with both flasks and bioreactors, hairy root cultures, bioconversions and metabolic regulations.

Neural networks modeling signal responses and taxol production of cultured Taxus chinensis cells induced by bio-elicitor

Quantitatively describing the signal transduction process is important for understanding the mechanism of signal regulation in cells,and thus,poses both a challenge and an opportunity for chemical and biochemical engineers.An artificial neural network(ANN),in which we took the signal molecules as neural nodes,was constructed to simulate the generation of active oxygen species(AOS)in Taxus chinensis cells induced by a bio-elicitor.The relative contents of AOS in cells predicted by the ANN model agreed well with the experimental data and three notable stages of AOS increase were observed from the 3D figure of AOS generation.The robustness of AOS trajectories indicated that signal regula-tion in vivo was an integral feedback control model that ensured the adaptation of Taxus chinensis to environmental stress.The artificial neural network was able to predict taxol production as well as determine the optimal concentration of oligosaccharides needed for it.

Bioreactor technology for clonal propagation of plants and metabolite production

Plant cell culture in bioreactors is an enabling tool for large scale production of clonal elite plants in agriculture, horticulture, forestry, pharmaceutical sectors, and for biofuel production. Advantages of bioreactors for plant cell culture have resulted in various types of bioreactors differing in design, operating technologies, instrumentations, and construction of culture vessels. In this review, different types of bioreactors for clonal propagation of plants and secondary metabolites production are discussed. Mechanical and biochemical parameters associated with bioreactor design, such as aeration, flow rate, mixing, dissolved oxygen, composition of built-up gas in the headspace, and pH of the medium, are pivotal for cell morphology, growth, and development of cells within tissues, embryos, and organs. The differences in such parameters for different bioreactor designs are described here, and correlated to the plant materials that have been successfully cultured in different types of bioreactors.