Plant in vitro culture for the production of antioxidants : A review

Plant cell and tissue cultures can be established routinely under sterile conditions from explants, such as plant leaves, stems, roots, meristems etc for both the ways for multiplication and extraction of secondary metabolites. Strain improvement, methods for the selection of high-producing cell lines, and medium optimizations can lead to an enhancement in secondary metabolite production. However, most often trials with plant cell cultures fail to produce the desired products. In such cases, strategies to improve the production of secondary metabolites must be considered. One of the main problems encountered is the lack of basic knowledge of the biosynthetic routes, and mechanisms responsible for the production of plant metabolites. Where the productivity of the desired metabolites is limited by the lack of particular precursors, biotransformation using an exogenous supply of biosynthetic precursors, genetic manipulation and metabolic engineering may improve the accumulation of compounds. Feedback inhibition of metabolic enzymes as well as inhibition of membrane transport can be eliminated by the accumulation of synthesized products in a second phase introduced into the aqueous medium. Organ cultures and in vitro biomass production often have sites of synthesis and storage of secondary metabolites in separate compartments. Elicitors, compounds triggering the formation of secondary metabolites, can be abiotic or biotic. Natural elicitors include polysaccharides such as pectin and chitosan, which are also used in the immobilization and permeabilization of plant cells. Immobilization with suitable bioreactor system provides several advantages, such as continuous process operation, but for the development of an immobilized plant cell culture process, natural or artifically induced secretion of the accumulated product into the surrounding medium is necessary. The present review highlights the nature, applications, perspective and scale up methods for the production of valuable secondary metabolites in vitro.

	 

	Key words: Plant cell cultures, secondary metabolites, biotransformation, biosynthetic pathways, elicitation, immobilization, bioreactors.

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A review on trends in production of secondary metabolites from higher plants by in vitro tissue, organ and cell cultures.

Plant in vitro culture for the production of antioxidants

In vitro manipulation and propagation of medicinal plants

Tissue culture of ornamental pot plant: A critical review on present scenario and future prospects

Flowers of Chrysanthemum morifolium Ramat cv. Lalima were greyed red and florets were flat spoon shaped. Ray florets after inoculation on the Murashige and Skoog's medium supplemented with 1.07 μM α-naphthaleneacetic acid and 8.87 μM benzyladenine were irradiated with γ-radiation (0.5 Gy and 1 Gy). All the regenerated shoots either from control or from γ-irradiated florets were isolated, rooted and transplanted in the field after hardening. Two mutants were obtained in the γ-irradiated plants (0.5 Gy). Both the mutants were yellow coloured but one having flat spoon shaped ray florets similar to the original cultivar, while the other having tubular florets. Both the mutants were propagated vegetatively and have produced true-to-type flowers.

Mutation in flower colour and shape of Chrysanthemum morifolium induced by γ-radiation

Ray florets of Chrysanthemum morifol ium Ramat. cvs. Flirt, Puja, Maghi and Sunil were treated with 500 and 1000 rad gamma rays and cultured on MS medium supplemented with different concentrations and combinations of growth regulators. The frequency of d irect shoot regeneration decreased in gamma-ray-treated florets. Radiation effect was found on plant -regeneration from gamma-ray-treated floret explants and also on plant height, size of leaf and flower. Five solid flower colour/floret shape mutants with slight changes in ray floret morphology have been detected and established. In vitro mutagenesis through direct regeneration helpe d in the development of solid mutants without di plontic selection in a relatively short period of time. IN the floriculture industry there is always demand for new and novel varieties. Mutation breeding is an established method for crop improvement and has played a major role in the development of many new flower colour/shape mutants in ornamentals 1–3 . Conventionally, in vegetatively propagated ornamentals, rooted cuttings are treated with gamma rays before planting. In these treated plants mutation appears as chimeras, which remains the main bottleneck in mutation breeding. In chimeric tissue, mutated cells are present along with the normal cells. During subsequent cell division, the mutated cells compete with the surrounding normal cells for survival (called diplontic selection). If these mutated cells survive in diplotic selection, they are expressed in plants. In our laboratory, a technique has been standardized for the management of such chimeric tissues through direct shoot regeneration from flower petals 4–6

In vitro mutagenesis - : a quick method for establishment of solid mutant in chrysanthemum

The commercial importance of linseed (Linum usitatissimum L.) has attracted breeders to increase its seed yield using various breeding approaches. Plant growth regulators (PGRs) have a significant role in enhancing yield and its related traits in linseed. In the present study, two plant growth hormones, auxin and gibberellic acid, were applied individually, as well as in combinations, in order to study their effect on yield and its components in "Neelam", which is a high yielding variety of linseed. A comparative study was done under pot and field condition. A combined dose of auxin (1.0 mg L-1) and gibberellin (200 mg L-1) is recommended for the enhancement of seed yield, whereas a 0.5 mg L-1 dose of auxin is recommended for the enhancement of vegetative growth. It was concluded that the plant growth regulators can be successfully employed to enhance the yield in this economically important oil seed crop.

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Effect of auxin and gibberellic acid on growth and yield components of linseed (Linum usitatissimum L.)

A protocol has been developed for differentiation of shoot buds directly from leaf segments of white marigold (Tagetes erecta L.). Leaf segments were taken from in vitro-proliferated shoots of white marigold established in aseptic culture from shoot tips of field-grown plants. Gibberellic acid (GA) played a significant role in the induction of shoot buds as well as in suppressing callus formation. Shoot buds were induced directly in Murashige and Skoog's (MS) medium supplemented with 14.43 μM GA and 4.44 μM 6-benzyladenine in the absence of any auxin. In this medium two to five shoot buds differentiated from the margins as well as leaf lamina of the lower petiolar segment within 4 wk of incubation. Differentiated shoots grew well and proliferated in the MS medium having 1.1 μM BA and 29.41 μM AgNO3, as it had a beneficial effect on the growth and proliferation of shoots. Shoots were excised, rooted in 0.27 μm α-naphthaleneacetic acid (NAA) and transplanted under glasshouse conditions, where they grew and flowered. Data on different morphological characters during flowering under field conditions were recorded for seed-grown control plants, tissue culture-raised primary regenerants (R0) and first-generation (R1) plants. It was found that all the economically desired characters of plant height, number and size of flowers per plant, number of viable seeds per flower, and days to full bloom, of the R1 generation plants were significantly better than the control, thus increasing the commercial value of the tissue culture-raised plants in successive generations.

Direct differentiation of shoot buds in leaf segments of white marigold (tagetes erecta l.)

Shoot cultures and callus cultures from roots and leaves of Hemidesmus indicus R. Br. (Asclepiadaceae) were established on Murashige and Skoog medium with various hormonal combinations. The production of antioxidants (lupeol, vanillin, and rutin) in shoot cultures, callus cultures derived from leaf cells and root cells, was compared with root and aerial portions of the parent plant. Shoot cultures and leaf callus cultures produced more antioxidants than root callus cultures. In vitro culture of this species might offer an alternative method for production of these important pharmaceuticals, which would reduce the collection pressure on this rare plant.

https://bioone.org/journals/In-Vitro-Cellular-and-Developmental-Biology---Plant/volume-41/issue-3/IVP2004627/IN-VITRO-BIOSYNTHESIS-OF-ANTIOXIDANTS-FROM-HEMIDESMUS-INDICUS-R-BR/10.1079/IVP2004627.pdf

Pratibha Misra

Papers

Mutation in flower colour and shape of Chrysanthemum morifolium induced by γ-radiation

In vitro mutagenesis - : a quick method for establishment of solid mutant in chrysanthemum

Effect of auxin and gibberellic acid on growth and yield components of linseed (Linum usitatissimum L.)

Direct differentiation of shoot buds in leaf segments of white marigold (tagetes erecta l.)

In vitro biosynthesis of antioxidants from hemidesmus indicus r. br. cultures